A novel method based on off-line membrane-supported liquid-liquid-liquid microextraction ( MS-LLLME ) combined with on-column anion-selective exhaustive injection ( ASEI ) capillary electrophoresis-ultraviolet ( CE-UV ) detection was established for the analysis of seven phytohormones ( abscisic acid ( ABA ) , jasmonic acid ( JA ) , 2,4-dichlorophenoxyacetic acid ( 2,4-D ) , 1-naphthalene acetic acid ( NAA ) , indole-3-acetic acid ( IAA ) , salicylic acid ( SA ) and gibberellic acid ( GA ) ) .

In MS-LLLME , the target phytohormones were extracted from the acid donor phase to the alkaline acceptor phase , and the acceptor solutions were directly analyzed by ASEI-CE-UV .

Under the optimal experimental conditions , the analytical performance of the method was evaluated .

The limits of detection ( LODs ) of ABA , JA , 2,4-D , NAA , IAA , SA and GA were determined to be 1.00 , 2.21 , 0.33 , 0.17 , 0.67 , 0.05 and 16.5ng/mL , respectively .

The relative standard deviations ( RSDs , n=7 ) ranged from 4.7 % to 12.9 % , and the enrichment factors were in the range of 307 to 20,160 .

The proposed method was successfully applied for the determination of multiple phytohormones in banana , cabbage and cucumber extracts , and ABA , IAA and SA were detected in these samples .

The recoveries for the spiked samples were in the range of 79.0 to 116.4 % .

The proposed method was demonstrated to be suitable for the simultaneous quantification of multiple phytohormones with high sensitivity and good sample cleanup ability .


The patatin-related phospholipase A ( pPLA ) hydrolyzes membrane glycerolipids to produce monoacyl compounds and free fatty acids .

Phospholipids are cleaved by pPLAIIα at the sn-1 and sn-2 positions , and galactolipids , including those containing oxophytodienoic acids , can also serve as substrates .

Ablation of pPLAIIα decreased lysophosphatidylcholine and lysophosphatidylethanolamine levels , but increased free linolenic acid .

pPLAIIα-deficient plants displayed a higher level of jasmonic acid and methyl jasmonate , as well as the oxylipin-biosynthetic intermediates 13-hydroperoxylinolenic acid and 12-oxophytodienoic acid than wild-type ( WT ) plants .

The expression of genes involved in oxylipin production was also higher in the pPLAIIα-deficient mutant than in WT plants .

The mutant plants lost water more quickly than WT plants .

The stomata of WT and mutant plants responded similarly to abscisic acid .

In response to desiccation , the mutant and WT leaves produced abscisic acid at the same rate , but , after 4 h of desiccation , the jasmonic acid level was much higher in mutant than WT leaves .

These results indicate that pPLAIIα negatively regulates oxylipin production and suggest a role in the removal of oxidatively modified fatty acids from membranes .


The cyclic derivative of 13(S)-hydroperoxolinolenic acid , 12-oxophytodienoic acid , serves as a signal transducer in higher plants , mediating mechanotransductory processes and plant defenses against a variety of pathogens , and also serves as a precursor for the biosynthesis of jasmonic acid , a mediator of plant herbivore defense .

Biosynthesis of 12-oxophytodienoic acid from alpha-linolenic acid occurs in plastids , mainly in chloroplasts , and is thought to start with free linolenic acid liberated from membrane lipids by lipase action .

In Arabidopsis thaliana , the glycerolipid fraction contains esterified 12-oxophytodienoic acid , which can be released enzymatically by sn1-specific , but not by sn2-specific , lipases .

The 12-oxophytodienoyl glycerolipid fraction was isolated , purified , and characterized .

The novel class of lipids is localized in plastids .

Purified monogalactosyl diglyceride was not converted to the sn1-(12-oxophytodienoyl ) derivative by the combined action of ( soybean ) lipoxygenase and ( A. thaliana ) allene oxide synthase , an enzyme ensemble that converts free alpha-linolenic acid to free 12-oxophytodienoic acid .

When leaves were wounded , a significant and transient increase in the level of (12-oxophytodienoyl)-monogalactosyl diglyceride was observed .

In A. thaliana , the major fraction of 12-oxophytodienoic acid occurs esterified at the sn1 position of the plastid-specific glycerolipid , monogalactosyl diglyceride .


When plants are attacked by pathogens , they defend themselves with an arsenal of defence mechanisms , both passive and active .

The active defence responses , which require de novo protein synthesis , are regulated through a complex and interconnected network of signalling pathways that mainly involve three molecules , salicylic acid ( SA ) , jasmonic acid ( JA ) , and ethylene ( ET ) , and which results in the synthesis of pathogenesis-related ( PR ) proteins .

Microbe or elicitor-induced signal transduction pathways lead to ( i ) the reinforcement of cell walls and lignification , ( ii ) the production of antimicrobial metabolites ( phytoalexins ) , and ( iii ) the production of reactive oxygen species ( ROS ) and reactive nitrogen species ( RNS ) .

Among the proteins induced during the host plant defence , class III plant peroxidases ( EC 1.11.1.7 ; hydrogen donor : H(2)O(2 ) oxidoreductase , Prxs ) are well known .

They belong to a large multigene family , and participate in a broad range of physiological processes , such as lignin and suberin formation , cross-linking of cell wall components , and synthesis of phytoalexins , or participate in the metabolism of ROS and RNS , both switching on the hypersensitive response ( HR ) , a form of programmed host cell death at the infection site associated with limited pathogen development .

The present review focuses on these plant defence reactions in which Prxs are directly or indirectly involved , and ends with the signalling pathways , which regulate Prx gene expression during plant defence .

How they are integrated within the complex network of defence responses of any host plant cell will be the cornerstone of future research .


Potential of MoSM1 , encoding for a cerato-platanin protein from Magnaporthe oryzae , in improvement of rice disease resistance was examined .

Transient expression of MoSM1 in rice leaves initiated hypersensitive response and upregulated expression of defense genes .

When transiently expressed in tobacco leaves , MoSM1 targeted to plasma membrane .

The MoSM1-overexpressing ( MoSM1-OE ) transgenic rice lines showed an improved resistance , as revealed by the reduced disease severity and decreased in planta pathogen growth , against 2 strains belonging to two different races of M. oryzae , causing blast disease , and against 2 strains of Xanthomonas oryzae pv . oryzae , causing bacterial leaf blight disease .

However , no alteration in resistance to sheath blight disease was observed in MoSM1-OE lines .

The MoSM1-OE plants contained elevated levels of salicylic acid ( SA ) and jasmonic acid ( JA ) and constitutively activated the expression of SA and JA signaling-related regulatory and defense genes .

Furthermore , the MoSM1-OE plants had no effect on drought and salt stress tolerance and on grain yield .

We conclude that MoSM1 confers a broad-spectrum resistance against different pathogens through modulating SA- and JA-mediated signaling pathways without any penalty on abiotic stress tolerance and grain yield , providing a promising potential for application of MoSM1 in improvement of disease resistance in crops .


Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones , including gibberellins ( GAs ) .

In this work , Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice ( Oryza sativa ) mutants , dy and dx , when the inoculated seedlings were supplied with [17,17 - 2H2]GA20-glucosyl ester or [ 17,17- 2H2]GA20-glucosyl ether .

Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17 - 2H2]GA20 and its subsequent 3beta-hydroxylation to [17,17 - 2H2]GA1 by the microorganism for the dy mutant , and by both the rice plant and microorganism for the dx mutant .


Phytoalexin synthesis is a defence-response- that is characterized by a requirement for a number of distinct elements , all of which must be present for the response to be expressed fully .

These same elements : a signal , a cellular receptor , a signal transduction system and a responsive metabolic system , are also used to describe a stimulus-response system .

A number of molecular species can function as signal molecules or elicitors of phytoalexin synthesis , including poly- and oligosaccharides , proteins and polypeptides , and fatty acids .

Few receptors for elicitors have been identified but those that have been are proteins located on the plasma membrane of the plant .

Induction of phytoalexin synthesis involves selective and co-ordinated activation of specific defence response genes , including those encoding the enzymes of phytoalexin synthesis , and these genes constitute the responsive metabolic system .

The separate , and distant , locations of the receptor and the responsive genes means that the event in which the signal is perceived by the receptor must be relayed to the genes by means of a second messenger system .

Several second messengers are candidates for such a coupling- or signal transduction-system , including udenosine-3',5'-cyclic monophosphate , Ca(2 + ) , diacylglycerol and inositol 1,4,5-trisphosphate , active oxygen species and jasmonic acid .

Each has been examined as a possible component of the signal transduction system mediating between the elicitor receptor interaction and the phytoalexin synthesis it induces .

Analysis of the signalling events is made complex by the simultaneous solicitation by the invading micro-organism of several defence responses , each of which might involve elements of a different signal system .

The same complexity is evident which the role of phytoalexin accumulation in resistance is analysed .

Evaluation of the contribution made by phytoalexin accumulation towards resistance has been attempted by the use of various inhibitors and enhancers of the process .

Transgenic and mutant plants with specific alterations in one or more ot those elements necessary for the plant to respond to the signals for phytoalexin synthesis and other defence responses , are beginning to aid resolution of the complex pattern ot signalling events and the respective roles of the inducible defence mechanisms in resistance .

CONTENTS Summary 1 I. Introduction 2 II .

Phytoalexin accumulation as a determinant of resistance 6 IV .

Elicitation of phytoalexin accumulation 11 References 34 .


Exposure of gibberellic acid-treated seedlings of a monoecious cucumber cultivar ; Chipper ' ( Cucumis sativus L. ) to ethylene caused thickening of the hypocotyl , inhibited longitudinal growth , and had no effect on fresh weight .

Downward curvature of cotyledons was increased by the presence of ethylene .

A gynoecious breeding line , ; Gy 3 , ' had thicker hypocotyls and displayed its cotyledons in a more downward position than ; Chipper ' .

Excised hypocotyls of the gynoecious seedlings produced three times as much ethylene as did the monoecious Chipper hypocotyls .

Thus , ethylene may play a role in the regulation of cucumber seedling morphology .


Rising atmospheric CO2 concentrations can affect the induced defense of plants against herbivory by chewing insects , but little is known about whether elevated CO2 can change the inducible defense of plants against herbivory by aphids , which are phloem-sucking rather than tissue-chewing insects .

Interactions between the green peach aphid Myzus persicae and four isogenic Arabidopsis thaliana genotypes including wild type and three induced defense pathway deficient mutants were examined under ambient and elevated CO2 .

Our data showed that elevated CO2 increased the population abundance of peach aphid when reared on wild type and SA-deficient mutant plants .

Regardless of aphid infestation , elevated CO2 decreased the jasmonic acid ( JA ) but increased the salicylic acid ( SA ) level in wild-type plants .

In addition , elevated CO2 increased SA level in SA-deficient mutant while did not change the JA level in JA-deficient mutant .

Pathway enrichment analysis based on high-throughput transcriptome sequencing suggested that CO2 level , aphid infestation , and their interactions ( respectively ) altered plant defense pathways .

Furthermore , qPCR results showed that elevated CO2 up-regulated the expression of SA-dependent defense genes but down-regulated the expression of JA/ethylene-dependent defense genes in wild-type plants infested by aphids .

The current study indicated that elevated CO2 tended to enhance the ineffective defense-SA signaling pathway and to reduce the effective defense-JA signaling pathway against aphids , which resulted in increased aphid numbers .


The tobacco N gene , a member of the Toll-interleukin 1 homology region/nucleotide binding site/leucine-rich repeat ( TIR-NBS-LRR ) class of resistance ( R ) genes , confers resistance to tobacco mosaic virus ( TMV ) .

We used a candidate gene approach to identify known defense genes that were also involved in N signaling .

The requirement for these genes was determined by downregulating their expression using the well-established tobacco rattle virus (TRV)-based virus-induced gene silencing ( VIGS ) .

Silencing of genes encoding a mitogen-activated protein kinase ( MAPK ) NTF6/NRK1 , or an MAPK kinase ( MAPKK ) MEK1/NQK1 , attenuated N-mediated resistance to TMV .

We also found that N resistance is compromised in plants in which expression of WRKY1-WRKY3 and MYB1 transcription factors were downregulated .

In addition , suppression of jasmonic acid ( JA ) signaling component COI1 ortholog affected N function .

However , downregulation of expression of CTR1 ortholog leads to more rapid hypersensitive response ( HR ) .

The involvement of these genes in N- and other R-gene-mediated defense provides further evidence for the convergence of downstream signaling pathways of different R genes .


A multiscaled ecophysiological model of barley ( Hordeum vulgare ) development is presented here .

The model is based on the new formalism of relational growth grammars ( RGG ) , an extension of L-systems , and implemented using the new modelling language XL .

It is executable in the interactive modelling platform GroIMP .

The model consists of a set of morphogenetic rules , combined with a metabolic regulatory network , which simulates the biosynthesis of gibberellic acid ( GA1 ) .

GA1 and two of its metabolic precursors are transported along the developing simulated structure .

Local concentrations of GA1 determine internode elongation .

Furthermore , virtual barley individuals are chosen interactively from a population , based on genotype , and ( sexual or asexual ) reproduction is simulated .

Genotype and phenotype of the population are visualized .

Seven Mendelian genes have been implemented in the model so far ; some of these directly influence the GA-regulation network .

The model exemplifies and validates the new formalism and modelling language .

RGG have the capability to represent genetic , metabolic and morphological aspects of plant development and reproduction , all within the same framework .


Studies of the singlet oxygen ( (1)O2)-overproducing flu and chlorina1 ( ch1 ) mutants of Arabidopsis ( Arabidopsis thaliana ) have shown that (1)O2-induced changes in gene expression can lead to either programmed cell death ( PCD ) or acclimation .

A transcriptomic analysis of the ch1 mutant has allowed the identification of genes whose expression is specifically affected by each phenomenon .

One such gene is OXIDATIVE SIGNAL INDUCIBLE1 ( OXI1 ) encoding an AGC kinase that was noticeably induced by excess light energy and (1)O2 stress conditions leading to cell death .

Photo-induced oxidative damage and cell death were drastically reduced in the OXI1 null mutant ( oxi1 ) and in the double mutant ch1*oxi1 compared with the wild type and the ch1 single mutant , respectively .

This occurred without any changes in the production rate of (1)O2 but was cancelled by exogenous applications of the phytohormone jasmonate .

OXI1-mediated (1)O2 signaling appeared to operate through a different pathway from the previously characterized OXI1-dependent response to pathogens and H2O2 and was found to be independent of the EXECUTER proteins .

In high-light-stressed plants , the oxi1 mutation was associated with reduced jasmonate levels and with the up-regulation of genes encoding negative regulators of jasmonate signaling and PCD .

Our results show that OXI1 is a new regulator of (1)O2-induced PCD , likely acting upstream of jasmonate .


It has been shown that indoleacetic acid ( IAA ) does not occur in developing grains of Hordeum vulgare L. ( barley ) , but that an unidentified indolic compound does .

This compound , designated ' A ' , was also found to be a product of the metabolism of exogenous IAA by barley .

The expression of the gibberellic acid effect was delayed for at least 8 h if grains were imbibed in a solution of IAA , and during this time , the IAA was metabolised .

The enzyme system involved could be peroxidase , which was active in the grains at all stages of their development and at maturity , and partially purified extracts of peroxidase were found to have considerable IAA oxidase activity .


The citrus rootstocks sour orange and Cleopatra mandarin display differential resistance against Tetranychus urticae .

Sour orange plants support reduced oviposition , growth rates and damage compared with Cleopatra mandarin plants .

Jasmonic acid signalling and flavonoid accumulation have been revealed as key mechanisms for the enhanced resistance of sour orange plants .

In this study , we observed that the release of T. urticae herbivore-induced plant volatiles ( HIPVs ) from sour orange plants has a marked repellent effect on conspecific mites associated with the production of the terpenes α-ocimene , α-farnesene , pinene and d-limonene , and the green leaf volatile 4-hydroxy-4-methyl-2-pentanone .

By contrast , T. urticae HIPVs from Cleopatra mandarin plants promote conspecific mite attraction associated with an increase in ( 2-butoxyethoxy ) ethanol , benzaldehyde and methyl salicylate levels .

HIPVs released from sour orange plants following T. urticae infestation induce resistance in Cleopatra mandarin plants , thereby reducing oviposition rates and stimulating the oxylipin biosynthetic gene lipoxygenase2 ( LOX2 ) .

Cleopatra HIPVs do not affect the response to T. urticae of these rootstocks .

We conclude that sour orange plants promote herbivore-induced resistance in Cleopatra mandarin plants and , despite the weak basal resistance of these rootstocks , herbivore resistance can be induced through the combination of HIPVs , such as α-ocimene and d-limonene .


The effects of phytohormones ( abscisic acid , gibberelic acid , and jasmonic acid ) and ambiol ( a synthetic growth regulator ) on processes of H+ transport across the plasmalemma were studied in membrane vesicles isolated from the parenchyma of potato ( Solanum tuberosum L. ) tubers .

Phytohormones and ambiol were tested either individually or in combinations .

Each of the substances tested changed the initial rate of H+ uptake by the vesicles .

Two signaling substances added to the incubation medium simultaneously modified the activity of each other .

It is suggested that the interaction of a signaling substance with components of the plasmalemma alters the responses of the membrane to other signaling molecules .


Jasmonates are essential engineers of plant defense responses against many pests , including herbivorous insects .

Herbivory induces the production of jasmonic acid ( JA ) and its bioactive conjugate jasmonoyl-L-isoleucine ( JA-Ile ) , which then triggers a large transcriptional reprogramming to promote plant acclimation .

The contribution of the JA pathway , including its components and regulators , to defense responses against insect herbivory can be evaluated by conducting bioassays with a wide range of host plants and insect pests .

Here , we describe a detailed and reproducible protocol for testing feeding behavior of the generalist herbivore Spodoptera littoralis on the model plant Arabidopsis thaliana and hence infer the contribution of JA-mediated plant defense responses to a chewing insect .


A rapid , selective , sensitive , accurate , and inexpensive immunosensor for gibberellin acid detection was designed by coupling immunoassay with the square wave anodic stripping voltammetry ( SWASV ) technique involving copper ion labeled antigen in the competitive immunoreaction .

The response signal expressed as the percentage of current reduction CR % ( y ) is linearly related to the concentration of GA ( x ) in the 1 microg/mL to approximately 150 microg/mL range with a regression equation of the form y = 0.44x + 15.59 and a correlation coefficient of 0.99 .

The results of the immunosensor assay were compared with those obtained by HPLC and ELISA , which show a satisfactory agreement .

The immunosensor was used to determine the GA content in the hybrid rice grain samples taken in the growing period .


• Owing to its evolutional plasticity and adaptability , barley ( Hordeum vulgare ) is one of the most widespread crops in the world .

Despite this evolutionary success , sexual reproduction of small grain cereals is poorly investigated , making discovery of novel genes and functions a challenging priority .

Barley gene Jekyll appears to be a key player in grain development ; however , its role in flowers has remained unknown .

• Here , we studied RNAi lines of barley , where Jekyll expression was repressed to different extents .

The impact of Jekyll on flower development was evaluated based on differential gene expression analysis applied to anthers and gynoecia of wildtype and transgenic plants , as well as using isotope labeling experiments , hormone analysis , immunogold- and TUNEL-assays and in situ hybridization .

• Jekyll is expressed in nurse tissues mediating gametophyte-sporophyte interaction in anthers and gynoecia , where JEKYLL was found within the intracellular membranes .

The repression of Jekyll impaired pollen maturation , anther dehiscence and induced a significant loss of fertility .

The presence of JEKYLL on the pollen surface also hints at possible involvement in the fertilization process .

• We conclude that the role of Jekyll in cereal sexual reproduction is clearly much broader than has been hitherto realized .


Chemically synthesized 2-hydroxyethyl jasmonate ( HEJA ) was for the first time employed to induce the ginsenoside biosynthesis and to manipulate the product heterogeneity in plant cell cultures .

The dose response and timing of HEJA elicitation were investigated in cell suspension cultures of Panax notoginseng .

The optimal concentration and timing of HEJA addition for both cell growth and ginsenoside accumulation was identified to be 200 microM added on day 4 .

It was interestingly found that HEJA could stimulate ginsenosides biosynthesis and change their heterogeneity more efficiently than methyl jasmonate ( MJA ) , i.e. , the total ginsenoside content and the Rb/Rg ratio increased about 60 and 30 % with HEJA elicitation than that by MJA , respectively .

The activity of Rb1 biosynthetic enzyme , i.e. , UDPG-ginsenoside Rd glucosyltransferase ( UGRdGT ) , was also higher in the former case .

A maximal production titer of ginsenoside Rg1 , Re , Rb1 , and Rd was 47.4+/-4.8 , 52.3+/-4.4 , 190+/-18 , and 12.1+/-2.5 mg/l with HEJA elicitation , which was about 1.3- , 1.3- , 1.7- , and 2.1-fold than that using MJA , respectively .

Early signal events in plant defense response , including oxidative burst and jasmonic acid ( JA ) biosynthesis , were also examined .

Levels of H2O2 and NO in medium and L-phenylalanine ammonia lyase activity in cells were not affected by addition of MJA and HEJA .

On the other hand , the JA content in cells was increased with external jasmonates elicitation , and it was inhibited with the addition of JA biosynthesis inhibitors .

The results suggest that oxidative burst might not be involved in the jasmonates-elicited signal transduction pathway , and MJA and HEJA may induce the ginsenoside biosynthesis via induction of endogenous JA biosynthesis and key enzymes ( such as UGRdGT ) in the ginsenoside biosynthetic pathway of P. notoginseng cells .

The information is useful for hyperproduction of plant-specific heterogeneous products .


Jasmonic acid and its derived metabolites ( JAs ) orchestrate plant defense against insects and fungi . 12-Oxo-phytodienoic acid ( OPDA ) , a JA precursor , has also been implicated in plant defense .

We sought to define JAs and OPDA functions through comparative defense susceptibility characteristics of three Arabidopsis ( Arabidopsis thaliana ) genotypes : aos , lacking JAs and OPDA ; opda reductase3 ( opr3 ) , deficient in JA production but can accumulate OPDA ; and transgenics that overexpress OPR3 .

opr3 , like aos , is susceptible to cabbage loopers ( Trichoplusia ni ) but , relative to aos , opr3 has enhanced resistance to a necrotrophic fungus .

Gas chromatography-mass spectrometry reveals that opr3 produces OPDA but no detectable JAs following wounding and looper infestation ; unexpectedly , substantial levels of JAs accumulate in opr3 upon fungal infection .

Full-length OPR3 transcripts accumulate in fungal-infected opr3 , potentially through splicing of the T-DNA containing intron .

Fungal resistance correlates with levels of JAs not OPDA ; therefore , opr3 resistance to some pests is likely due to JA accumulation , and signaling activities ascribed to OPDA should be reassessed because opr3 can produce JAs .

Together these data ( 1 ) reinforce the primary role JAs play in plant defense against insects and necrotrophic fungi , ( 2 ) argue for a reassessment of signaling activities ascribed to OPDA , and ( 3 ) provide evidence that mutants with intron insertions can retain gene function .


Artemisinin is a type of sesquiterpene lactone well known as an antimalarial drug , and is specifically produced in glandular trichomes of Artemisia annua .

However , the regulatory network for the artemisinin biosynthetic pathway remains poorly understood .

Exploration of trichome-specific transcription factors would facilitate the elucidation of regulatory mechanism of artemisinin biosynthesis .

The WRKY transcription factor GLANDULAR TRICHOME-SPECIFIC WRKY 1 ( AaGSW1 ) was cloned and analysed in A. annua .

AaGSW1 exhibited similar expression patterns to the trichome-specific genes of the artemisinin biosynthetic pathway and AP2/ERF transcription factor AaORA .

A β-glucuronidase ( GUS ) staining assay further demonstrated that AaGSW1 is a glandular trichome-specific transcription factor .

AaGSW1 positively regulates CYP71AV1 and AaORA expression by directly binding to the W-box motifs in their promoters .

Overexpression of AaGSW1 in A. annua significantly improves artemisinin and dihydroartemisinic acid contents ; moreover , AaGSW1 can be directly regulated by AaMYC2 and AabZIP1 , which are positive regulators of jasmonate (JA)- and abscisic acid (ABA)-mediated artemisinin biosynthetic pathways , respectively .

These results demonstrate that AaGSW1 is a glandular trichome-specific WRKY transcription factor and a positive regulator in the artemisinin biosynthetic pathway .

Moreover , we propose that two trifurcate feed-forward pathways involving AaGSW1 , CYP71AV1 and AaMYC2/AabZIP1 function in the JA/ABA response in A. annua .


The necrotrophic fungus Botrytis cinerea causes devastating pre- and post-harvest yield losses in grapevine ( Vitis vinifera L. ) .

Although B. cinerea has been well-studied in different plant species , there is limited information related to the resistance and susceptibility mechanisms of Vitis genotypes against B. cinerea infection .

In the present study , leaves and berries of twenty four grape genotypes were evaluated against B. cinerea infection .

According to the results , one genotype ( Ju mei gui ) was highly resistant ( HR ) , one genotype ( Kyoho ) was resistant ( R ) , eight genotypes were susceptible ( S ) , and fourteen genotypes were highly susceptible ( HS ) against infection of B. cinerea in leaves .

Whereas in the case of B. cinerea infection in grape berry , three genotypes were found to be highly resistant , three resistant , eleven genotypes susceptible , and seven were highly susceptible .

To further explore the mechanism of disease resistance in grapevine , we evaluated " Ju mei gui " and " Summer black " in terms of B. cinerea progression , reactive oxygen species reactions , jasmonic acid contents , and the activities of antioxidant enzymes in leaf and fruit .

We surmise that the resistance of " Ju mei gui " is due to seized fungal growth , minor reactive oxygen species ( ROS ) production , elevated antioxidant enzyme activity , and more jasmonic acid ( JA ) contents .

This study provides insights into the resistance and susceptibility mechanism of Vitis genotypes against B. cinerea .

This will help for the selection of appropriate germplasm to explore the molecular basis of disease resistance mechanisms in grapevine .


Abscisic-acid ( ABA ) levels were determined in triticale 6A190 kernels at various stages of development from anthesis to maturity .

22 d post-anthesis and declined rapidly 12 d later .

Associated with drying of the kernel at maturity there was a rapid increase in the endogenous level of α-amylase , apparently based upon de-novo synthesis .

Simultaneously there were visible signs of degradation of the large starch grains in the starchy endosperm .

Regulation of α-amylase production in the kernel by exogenous gibberellic acid ( GA3 ) was only evident in the almost mature kernel ( 30 - 40 d after anthesis ) and then only if these kernels were first dried artificially .

Furthermore , little α-amylase mRNA could be detected prior to kernel maturity and water loss .

Thus , the high levels of gibberellin ( GA ) that have been found early in kernel development in cereals do not appear to control the later production of α-amylase and onset of kernel germination in the ear of triticale .

However , the presence of high levels of ABA until maturity could prevent early germination and premature production of α-amylase .

Kernels of triticale 6A190 are characteristically shrivelled and non-dormant at maturity .

The relevance of changes in the capacity of kernels to respond to and produce GA and ABA is discussed in relation to problems of harvest dormancy in cereals .


The plant hormone ethylene is involved in many physiological processes , including plant growth , development and senescence .

Ethylene also plays a pivotal role in plant response or adaptation under biotic and abiotic stress conditions .

In plants , ethylene production often enhances the tolerance to sub-optimal environmental conditions .

This role is particularly important from both ecological and agricultural point of views .

Among the abiotic stresses , the role of ethylene in plants under nutrient stress conditions has not been completely investigated .

In literature few reports are available on the interaction among ethylene and macro- or micro-nutrients .

However , the published works clearly demonstrated that several mineral nutrients largely affect ethylene biosynthesis and perception with a strong influence on plant physiology .

The aim of this review is to revisit the old findings and recent advances of knowledge regarding the sub-optimal nutrient conditions on the effect of ethylene biosynthesis and perception in plants .

The effect of deficiency or excess of the single macronutrient or micronutrient on the ethylene pathway and plant responses are reviewed and discussed .

The synergistic and antagonist effect of the different mineral nutrients on ethylene plant responses is critically analyzed .

Moreover , this review highlights the status of information between nutritional stresses and plant response , emphasizing the topics that should be further investigated .


Global warming frequently leads to extreme temperatures , which pose a serious threat to the growth , development , and yield formation of crops such as maize .

This study aimed to deeply explore the molecular mechanisms of young ear development under heat stress .

We selected the heat-tolerant maize variety Zhengdan 958 ( T ) and heat-sensitive maize variety Xianyu 335 ( S ) , and subjected them to heat stress in the V9 ( 9th leaf ) , V12 ( 12th leaf ) , and VT ( tasseling ) growth stages .

We combined analysis of the maize phenotype with omics technology and physiological indicators to compare the differences in young ear morphology , total number of florets , floret fertilization rate , grain abortion rate , number of grains , and main metabolic pathways between plants subjected to heat stress and those left to develop normally .

The results showed that after heat stress , the length and diameter of young ears , total number of florets , floret fertilization rate , and number of grains all decreased significantly , whereas the length of the undeveloped part at the top of the ear and grain abortion rate increased significantly .

In addition , the differentially expressed genes ( DEGs ) in young ears were significantly enriched in the hormone signaling pathways .

The endogenous hormone content in young ears exhibited different changes : zeatin ( ZT ) and zeatin riboside ( ZR ) decreased significantly , but gibberellin acid(3 ) ( GA(3 ) ) , gibberellin acid(4 ) ( GA(4 ) ) , and abscisic acid ( ABA ) increased significantly , in ears subjected to heat stress .

In the heat-tolerant maize variety , the salicylic acid ( SA ) , and jasmonic acid ( JA ) content in the vegetative growth stage also increased in ears subjected to heat stress , whereas the opposite effect was observed for the heat-sensitive variety .

The changes in endogenous hormone content of young ears that were subjected to heat stress significantly affected ear development , resulting in a reduction in the number of differentiated florets , fertilized florets and grains , which ultimately reduced the maize yield .


BACKGROUND : The valuable medicinal plant Panax ginseng has high pharmaceutical efficacy because it produces ginsenosides .

However , its yields decline because of a root-rot disease caused by Ilyonectria mors-panacis .

Because species within Ilyonectria showed variable aggressiveness by altering ginsenoside concentrations in inoculated plants , we investigated how such infections might regulate the biosynthesis of ginsenosides and their related signaling molecules .

METHODS : Two-year-old ginseng seedlings were treated with I. mors-panacis and I. robusta .

Roots from infected and pathogen-free plants were harvested at 4 and 16 days after inoculation .

We then examined levels or/and expression of genes of ginsenosides , salicylic acid ( SA ) , jasmonic acid ( JA ) , and reactive oxygen species ( ROS ) .

We also checked the susceptibility of those pathogens to ROS .

RESULTS : Ginsenoside biosynthesis was significantly suppressed and increased in response to infection by I. mors-panacis and I. robusta , respectively .

Regulation of JA was significantly higher in I. robusta-infected roots , while levels of SA and ROS were significantly higher in I. mors-panacis-infected roots .

Catalase activity was significantly higher in I. robusta-infected roots followed in order by mock roots and those infected by I. mors-panacis .

Moreover , I. mors-panacis was resistant to ROS compared with I. robusta .

CONCLUSION : Infection by the weakly aggressive I. robusta led to the upregulation of ginsenoside production and biosynthesis , probably because only a low level of ROS was induced .

In contrast , the more aggressive I. mors-panacis suppressed ginsenoside biosynthesis , probably because of higher ROS levels and subsequent induction of programmed cell death pathways .

Furthermore , I. mors-panacis may have increased its virulence by resisting the cytotoxicity of ROS .


Wilt caused by Verticillium dahliae significantly reduces cotton yields , as host resistance in commercially cultivated Gossypium species is lacking .

Understanding the molecular basis of disease resistance in non-commercial Gossypium species could galvanize the development of Verticillium wilt resistance in cultivated species .

Nucleotide-binding site leucine-rich repeat ( NBS-LRR ) proteins play a central role in plant defence against pathogens .

In this study , we focused on the relationship between a locus enriched with eight NBS-LRR genes and Verticillium wilt resistance in G. barbadense .

Independent virus-induced gene silencing of each of the eight NBS-LRR genes in G. barbadense cultivar Hai 7124 revealed that silencing of GbaNA1 alone compromised the resistance of G. barbadense to V. dahliae isolate Vd991 .

In cultivar Hai 7124 , GbaNA1 could be induced by V. dahliae isolate Vd991 and by ethylene , jasmonic acid and salicylic acid .

Nuclear protein localization of GbaNA1 was demonstrated by transient expression .

Sequencing of the GbaNA1 orthologue in nine G. hirsutum accessions revealed that all carried a non-functional allele , caused by a premature peptide truncation .

In addition , all 10 G. barbadense and nine G. hirsutum accessions tested carried a full-length ( ∼1140 amino acids ) homologue of the V. dahliae race 1 resistance gene Gbve1 , although some sequence polymorphisms were observed .

Verticillium dahliae Vd991 is a non-race 1 isolate that lacks the Ave1 gene .

Thus , the resistance imparted by GbaNA1 appears to be mediated by a mechanism distinct from recognition of the fungal effector Ave1 .


A nonpathogenic rhizobacterium , Pseudomonas putida LSW17S , elicited systemic protection against Fusarium wilt and pith necrosis caused by Fusarium oxysporum f. sp. lycopersici and P. corrugata in tomato ( Lycopersicon esculentum L. ) .

LSW17S also confers disease resistance against P. syringae pv . tomato DC3000 ( DC3000 ) on Arabidopsis ecotype Col-0 .

To investigate mechanisms underlying disease protection , expression patterns of defense-related genes PR1 , PR2 , PR5 , and PDF1.2 and cellular defense responses such as hydrogen peroxide accumulation and callose deposition were investigated .

LSW17S treatment exhibited the typical phenomena of priming .

Strong and faster transcription of defense-related genes was induced and hydrogen peroxide or callose were accumulated in Arabidopsis treated with LSW17S and infected with DC3000 .

In contrast , individual actions of LSW17S and DC3000 did not elicit rapid molecular and cellular defense responses .

Priming by LSW17S was translocated systemically and retained for more than 10 days .

Treatment with LSW17S reduced pathogen proliferation in Arabidopsis ecotype Col-0 expressing bacterial NahG ; however , npr1 , etr1 , and jar1 mutations impaired inhibition of pathogen growth .

Cellular and molecular priming responses support these results .

In sum , LSW17S primes Arabidopsis for NPR1- , ethylene- , and jasmonic acid-dependent disease resistance , and efficient molecular and cellular defense responses .


BACKGROUND : Breeding for genes controlling key agronomic traits is an important goal of rice genetic improvement .

To gain insight into genes controlling grain morphology , we screened M(3 ) plants derived from 1,000 whole-genome sequenced ( WGS ) M(2 ) Kitaake mutants to identify lines with altered grain size .

RESULTS : In this study , we isolated a mutant , named fast-neutron ( FN ) 60 - 4 , which exhibits a significant reduction in grain size .

We crossed FN60 - 4 with the parental line Kitaake and analyzed the resulting backcross population .

Segregation analysis of 113 lines from the BC(2)F(2 ) population revealed that the mutant phenotype is controlled by a single semi-dominant locus .

Mutant FN60 - 4 is reduced 20 % in plant height and 8.8 % in 1000-grain weight compared with Kitaake .

FN60 - 4 also exhibits an 8 % reduction in cell number and a 9 % reduction in cell length along the vertical axis of the glume .

We carried out whole-genome sequencing of DNA pools extracted from segregants with long grains or short grains , and revealed that one gene , LOC_Os09g02650 , cosegregated with the grain size phenotype in the BC(1)F(2 ) and BC(2)F(2 ) populations .

This mutant allele was named grain shape 9 - 1 ( gs9 - 1 ) .

gs9 - 1 carries a 3-bp deletion that affects two amino acids .

This locus is a new allele of the BC12/GDD1/MTD1 gene that encodes a kinesin-like protein involved in cell-cycle progression , cellulose microfibril deposition and gibberellic acid ( GA ) biosynthesis .

The GA biosynthesis-related gene KO2 is down-regulated in gs9 - 1 .

The dwarf phenotype of gs9 - 1 can be rescued by adding exogenous GA(3 ) .

In contrast to the phenotypes for the other alleles , the gs9 - 1 is less severe , consistent with the nature of the mutation , which does not disrupt the open reading frame as observed for the other alleles .

CONCLUSIONS : In this study , we isolated a mutant , which exhibits altered grain shape and identified the mutated gene , gs9 - 1 .

Our study reveals that gs9 - 1 is a semi-dominant gene that carries a two-amino acid mutation .

gs9 - 1 is allelic to the BC12/GDD1/MTD1 gene involved in GA biosynthesis .

These results demonstrate the efficiency and convenience of cloning genes from the whole-genome sequenced Kitaake mutant population to advance investigations into genes controlling key agronomic traits in rice .


In plants , 14 - 3 - 3 proteins are important modulators of protein-protein interactions in response to environmental stresses .

The aim of the present work was to characterize one Opuntia ficus-indica 14 - 3 - 3 and get information about its client proteins .

To achieve this goal , O. ficus-indica 14 - 3 - 3 cDNA , named as Op14 - 3 - 3 μ , was amplified by 3'-RACE methodology .

Op14 - 3 - 3 μ contains an Open Reading Frame of 786 bp encoding a 261 amino acids protein .

Op14 - 3 - 3 μ cDNA was cloned into a bacterial expression system and recombinant protein was purified .

Differential Scanning Fluorimetry , Dynamic Light Scattering , and Ion Mobility-Mass Spectrometry were used for Op14 - 3 - 3 μ protein characterization , and Affinity-Purification-Mass Spectrometry analysis approach was used to obtain information about their potential client proteins .

Pyrophosphate-fructose 6-phosphate 1-phosphotransferase , ribulose bisphosphate carboxylase large subunit , and vacuolar-type H(+)-ATPase were identified .

Interestingly chorismate mutase p-prephenate dehydratase was also identified .

Op14 - 3 - 3 μ down-regulation was observed in Opuntia calluses when they were induced with Jasmonic Acid , while increased accumulation of Op14 - 3 - 3 μ protein was observed .

The putative interaction of 14 - 3 - 3 μ with chorismate mutase , which have not been reported before , suggest that Op14 - 3 - 3 μ could be an important regulator of metabolites biosynthesis and responses to stress in Opuntia spp .

SIGNIFICANCE : Opuntia species are important crops in arid and semiarid areas worldwide , but despite its relevance , little information about their tolerance mechanism to cope with harsh environmental conditions is reported .

14 - 3 - 3 proteins have gained attention due to its participation as protein-protein regulators and have been linked with primary metabolism and hormones responses .

Here we present the characterization of the first Opuntia ficus-indica 14 - 3 - 3 ( Op14 - 3 - 3 ) protein using affinity purification-mass spectrometry ( AP-MS ) strategy .

A novel Op14 - 3 - 3 client protein has been identified ; the chorismate mutase p-prephenate dehydratase , key enzyme that links the primary with secondary metabolism .

The present results open new questions about the Opuntia spp .

pathways mechanisms in response to environmental stress and the importance of 14 - 3 - 3 proteins in betalains biosynthesis .


The rice pathogenesis-related protein OsPR10a was scarcely expressed in OsCDPK1-silenced ( Ri-1 ) rice , which was highly sensitive to pathogen infection .

After inoculating the leaves with bacterial blight ( Xanthomonas oryzae pv . oryzae ; Xoo ) , we found that the expression of OsPR10a was up- and down-regulated in OEtr-1 ( overexpression of the constitutively active truncated form of OsCDPK1 ) and Ri-1 rice plants , respectively .

OsPR10a and OsCDPK1 showed corresponding expression patterns and were up-regulated in response to the jasmonic acid , salicylic acid and Xoo treatments , and OsPR1 and OsPR4 were significantly up-regulated in OEtr-1 .

These results suggest that OsCDPK1 may be an upstream regulator involved in rice innate immunity and conferred broad-spectrum of disease resistance .

Following the Xoo inoculation , the OEtr-1 and Ri-1 seedlings showed enhanced and reduced disease resistance , respectively .

The dihybrid rice Ri-1/OsPR10a-Ox not only bypassed the effect of OsCDPK1 silencing on the susceptibility to Xoo but also showed enhanced disease resistance and , consistent with Ri-1 phenotypes , increased plant height and grain size .

Our results reveal that OsCDPK1 plays novel key roles in the cross-talk and mediation of the balance between stress response and development and provides a clue for improving grain yield and disease resistance simultaneously in rice .


GIBBERELLIN INSENSITIVE DWARF1 ( GID1 ) encodes a soluble gibberellin ( GA ) receptor that shares sequence similarity with a hormone-sensitive lipase ( HSL ) .

Previously , a yeast two-hybrid ( Y2H ) assay revealed that the GID1-GA complex directly interacts with SLENDER RICE1 ( SLR1 ) , a DELLA repressor protein in GA signaling .

Here , we demonstrated , by pull-down and bimolecular fluorescence complementation ( BiFC ) experiments , that the GA-dependent GID1-SLR1 interaction also occurs in planta .

GA(4 ) was found to have the highest affinity to GID1 in Y2H assays and is the most effective form of GA in planta .

Domain analyses of SLR1 using Y2H , gel filtration , and BiFC methods revealed that the DELLA and TVHYNP domains of SLR1 are required for the GID1-SLR1 interaction .

To identify the important regions of GID1 for GA and SLR1 interactions , we used many different mutant versions of GID1 , such as the spontaneous mutant GID1s , N- and C-terminal truncated GID1s , and mutagenized GID1 proteins with conserved amino acids replaced with Ala. The amino acid residues important for SLR1 interaction completely overlapped the residues required for GA binding that were scattered throughout the GID1 molecule .

When we plotted these residues on the GID1 structure predicted by analogy with HSL tertiary structure , many residues were located at regions corresponding to the substrate binding pocket and lid .

Furthermore , the GA-GID1 interaction was stabilized by SLR1 .

Based on these observations , we proposed a molecular model for interaction between GA , GID1 , and SLR1 .


Fusarium species cause serious diseases in cereal staple food crops such as wheat and maize .

Currently , the mechanisms underlying resistance to Fusarium-caused diseases are still largely unknown .

In the present study , we employed a combined proteomic and transcriptomic approach to investigate wheat genes responding to F. graminearum infection that causes Fusarium head blight ( FHB ) .

We found a total of 163 genes and 37 proteins that were induced by infection .

These genes and proteins were associated with signaling pathways mediated by salicylic acid ( SA ) , jasmonic acid ( JA ) , ethylene ( ET ) , calcium ions , phosphatidic acid ( PA ) , as well as with reactive oxygen species ( ROS ) production and scavenging , antimicrobial compound synthesis , detoxification , and cell wall fortification .

We compared the time-course expression profiles between FHB-resistant Wangshuibai plants and susceptible Meh0106 mutant plants of a selected set of genes that are critical to the plants ' resistance and defense reactions .

A biphasic phenomenon was observed during the first 24 h after inoculation ( hai ) in the resistant plants .

The SA and Ca(2 + ) signaling pathways were activated within 6 hai followed by the JA mediated defense signaling activated around 12 hai .

ET signaling was activated between these two phases .

Genes for PA and ROS synthesis were induced during the SA and JA phases , respectively .

The delayed activation of the SA defense pathway in the mutant was associated with its susceptibility .

After F. graminearum infection , the endogenous contents of SA and JA in Wangshuibai and the mutant changed in a manner similar to the investigated genes corresponding to the individual pathways .

A few genes for resistance-related cell modification and phytoalexin production were also identified .

This study provided important clues for designing strategies to curb diseases caused by Fusarium .


Harvestable , starch-storing organs of plants , such as fleshy taproots and tubers , are important agronomic products that are also suitable target organs for use in the molecular farming of recombinant proteins due to their strong sink strength .

To exploit a promoter directing strong expression restricted to these storage organs , we isolated the promoter region ( 3.0 kb ) of SRD1 from sweetpotato ( Ipomoea batatas cv . ' White Star ' ) and characterized its activity in transgenic Arabidopsis , carrot , and potato using the β-glucuronidase ( GUS ) gene ( uidA ) as a reporter gene .

The SRD1 promoter conferred root-specific expression in transgenic Arabidopsis , with SRD1 promoter activity increasing in response to exogenous IAA .

A time-course study of the effect of IAA ( 50 μM ) revealed a maximum increase in SRD1 promoter activity at 24 h post-treatment initiation .

A serial 5 ' deletion analysis of the SRD1 promoter identified regions related to IAA-inducible expression as well as regions containing positive and negative elements , respectively , controlling the expression level .

In transgenic carrot , the SRD1 promoter mediated strong taproot-specific expression , as evidenced by GUS staining being strong in almost the entire taproot , including secondary phloem , secondary xylem and vascular cambium .

The activity of the SRD1 promoter gradually increased with increasing diameter of the taproot in the transgenic carrot and was 10.71-fold higher than that of the CaMV35S promoter .

The SRD1 promoter also directed strong tuber-specific expression in transgenic potato .

Taken together , these results demonstrate that the SRD1 promoter directs strong expression restricted to the underground storage organs , such as fleshy taproots and tubers , as well as fibrous root tissues .


The present study was aimed to investigate the effects of subacute and subchronic treatment of some plant growth regulators ( PGRs ) , such as abscisic acid ( ABA ) and gibberellic acid ( GA3 ) , on neurological and immunological biomarkers in various tissues of rats .

The activities of acetylcholinesterase ( AChE ) and butrylcholinesterase ( BChE ) were selected as biomarkers for neurotoxic biomarkers .

Adenosine deaminase ( ADA ) and myeloperoxidase ( MPO ) were measured as indicators for immunotoxic investigation purpose .

Wistar albino rats were orally administered with 25 and 50 ppm of PGRs ad libitum for 25 - 50 days continuously with drinking water .

The treatment of PGRs caused different effects on the activities of enzymes .

Results showed that the administrations of ABA and GA3 increased AChE and BChE activities in some tissues of rats treated with both the dosages and periods of ABA and GA3 .

With regard to the immunotoxic effects , ADA activity fluctuated , while MPO activity increased after subacute and subchronic exposure of treated rat tissues to both dosages when compared with the controls .

The observations presented led us to conclude that the administrations of PGRs at subacute and subchronic exposure increased AChE , BChE , and MPO activities , while fluctuating the ADA activity in various tissues of rats .

This may reflect the potential role of these parameters as useful biomarkers for toxicity of PGRs .


Jasmonic acid is a carbocyclic fatty acid that is biosynthesized from alpha-linolenic acid in several steps .

The formation of the ring structure of jasmonic acid is catalyzed by the enzyme allene oxide cyclase ( EC 5.3.99.6 ) and involves the cyclization of an unstable allene oxide into the cyclopentenone 12-oxo-10,15(Z)-phytodienoic acid .

In this study , a number of allene oxides were generated , and their enzymatic and nonenzymatic cyclization into cyclopentenones was investigated .

Nonenzymatic cyclization was observed with allene oxides having one pair of conjugated double bonds and an additional isolated double bond in the beta , gamma position relative to the epoxide group , i.e. , the partial structure 4,5-epoxy-1,3,7-octatriene .

Enzymatic cyclization took place provided that this structural element was inserted in the fatty acid chain with its epoxide group in the n-6,7 position and the isolated double bond in the n-3 position .

A number of oxygenated fatty acids having structural features in common with the natural allene oxides were tested as inhibitors of allene oxide cyclase .

Fatty acids having an allene oxide structure in the n-6,7 position but lacking the double bond in the n-3 position , as well as fatty acids having a saturated epoxide group in the n-6,7 position , served as competitive inhibitors of the enzyme .

Data on the substrate specificity of allene oxide synthase ( EC 4.2.1.92 ) from corn seeds indicated that fatty acid hydroperoxides with a double bond at n-3 and with the hydroperoxide function at n-6 exhibit the highest affinity but the slowest reaction velocity .


Auxin is one of the most important phytohormones and exerts pleiotropic effects on plant growth and development .

Aux/IAA and auxin response factor ( ARF ) are two important protein families that are well recognized for their roles in auxin-mediated responses .

Aux/IAA proteins are short-lived transcriptional regulators that mediate auxin responses through interaction with ARF transcription factors .

Here , we systematically compared the genomic organization of the two families in rice .

The expression profiles of both families were compared to show possible association of the two gene families at expression level , which would help reveal their synergistic relationships and functions .

The expression profile analysis of Aux/IAA and ARF genes in 30 organs/tissues ( collected from an entire life cycle of rice ) suggested that Aux/IAA and ARF genes are expressed in very diverse patterns .

In general , the genes showing similar expression patterns tended to be in the same phylogenetic subgroup even though their expression patterns were not always the same .

Hierarchical cluster analysis revealed that there are eight pairs of IAA and ARF genes , with each pair showing highly correlated expression .

The expression levels of the IAA gene family were also checked under various hormone treatments including abscisic acid , kinetin , gibberellin , jasmonic acid , auxin and brassinolide .

The results indicated that most of the IAA genes respond to at least one of the treatments .

Furthermore , DNA chip and real-time PCR results show that many genes in these families were responsive to various abiotic stresses , indicating an interaction between plant growth and abiotic stress .

The effect of abiotic stress on plant growth and auxin distribution was further confirmed with the root growth of DR5-GUS transgenic rice under mannitol treatment , in which a close association between mannitol-induced changes of auxin distribution and root growth was observed .


Gibberellic acid ( GA(3 ) ) is one of the plant growth regulators which improve salt tolerance and mitigate the salt stress impact on plants .

The extant analysis was carried out to study the effect of GA(3 ) and different salt concentrations on seed germination and physiological parameters of oat cultivars .

Oats is substantially less tolerant to salt than wheat and barley .

Experimentation was conducted as factorial with Completely Randomized Block Design with three replicates .

Different concentration of NaCl salt ( ( 25 , 50 , 75 and 100 mM ) were used in test control group and 100 and 150 ppm of GA(3 ) were used in two group by pre-treated ( after 24 h of the seed soaking ) and plants were analyzed on 15th day .

Results indicate that increasing salinity would decrease the germination percentage and growth parameter in three oat cultivars .

Quotes data indicating a 13 % , 19.9 % and 32.48 % in cultivars NDO-2 , UPO-212 and UPO-94 germination reduction when soil salinity reaches 50 mM. A 36.02 % , 47.33 % and 56.365 reduction in germination is likely when soil salinity reaches 100 mM respectively same cultivars .

Seeds treated with GA(3 ) significantly promoted the percentage of germination , shoot and root length , total fresh and dry weight of seedling , tissue water content and seedling vigor index by NDO-2 and UPO-212 under different saline concentration .

The maximum average of germination and growth parameters were observed from 150 ppm GA(3 ) treated seeds .

But this concentration was significantly inhibited root length in sensitive cultivar UPO-94 at 75 and 100 mM salt as compared to 100 ppm .

We observed that , the high concentration of GA(3 ) was not suitable for sensitive oat cultivars .

Because the plant root are the real workforce behind any plants success .

Thus , it may be concluding that , GA(3 ) treatment could curtail the toxic effect of salinity by increasing germination percentage and shoot and root length , total fresh and dry weight , tissue water content and seedling vigor index in tolerant cultivar .


Recent evidence suggests that oxidized lipid-derived molecules play significant roles in inducible plant defence responses against microbial pathogens , either by directly deterring parasite multiplication , or as signals involved in the induction of sets of defence genes .

The synthesis of these oxylipins was hypothesized to be initiated by the phospholipase A2-mediated release of unsaturated fatty acids from membrane lipids .

Here , we demonstrate that , in tobacco leaves reacting hypersensitively to tobacco mosaic virus , a strong increase in soluble phospholipase A2 ( PLA2 ) activity occurs at the onset of necrotic lesion appearance .

This rapid PLA2 activation occurred before the accumulation of 12-oxophytodienoic and jasmonic acids , two fatty acid-derived defence signals .

Three PLA2 isoforms were separated and the most active enzyme was partially purified , its N-terminal sequence displaying similarity with patatin , the major storage protein in potato tubers .

Three related tobacco patatin-like cDNAs , called NtPat1 , NtPat2 and NtPat3 , were cloned , with NtPat2 encoding the PLA2 isolated from infected leaves .

RT-PCR experiments showed a rapid transcriptional activation of the three NtPat genes in virus-infected leaves , preceding the increase in PLA2 activity .

Recombinant NtPat1 and NtPat3 enzymes were active in an assay using labelled bacterial membranes , and also displayed high bona fide PLA2 activity on phosphatidylcholine substrate .

These results point to a possible new role of patatin-like phospholipases in inducible plant defence responses .

The induction kinetics together with the enzymatic activity data indicate that the NtPat proteins may provide precursors for oxylipin synthesis during the hypersensitive response to pathogens .


Oxophytodienoate reductases ( OPRs ) are a small group of flavin-dependent oxidoreductases in plants .

In this study , a new member of the OPR gene family ( HvOPR2 ) was cloned from barley ( Hordeum vulgare L. ) using reverse transcription polymerase chain reaction ( RT-PCR ) .

The full-length cDNA of HvOPR2 was 1,206 bp with an open reading frame of 1,101 bp , encoding a 366 amino acids long polypeptide with a predicted molecular weight of 40.52 and a theoretical isoelectric point of 6.21 .

The corresponding genomic clone of HvOPR2 was isolated using the PCR amplification technique and was found to consist of five exons and four introns .

Bioinformatic analysis revealed that the deduced HvOPR2 has a considerable homology with other plant OPRs and possessed the flavin oxidoreductase/NADH oxidase substrate-binding domain .

Phylogenetic analysis showed that HvOPR2 codes for the OPR of subgroup I , which contains enzymes that are not required for jasmonic acid biosynthesis .

Time-course transcriptional profiling of HvOPR2 was analyzed in response to a variety of abiotic stresses and hormonal treatments by semi-quantitative RT-PCR .

The HvOPR2 gene was induced in response to drought , hydrogen peroxide , and wounding .

Moreover , the corresponding mRNA transcripts were increased in response to jasmonic acid and salicylic acid , but not in response to abscisic acid .

These results strongly suggested a role for HvOPR2 in barley defense/response to abiotic stresses and signaling molecules .


The oxidative deamination of N-methylputrescine is an essential step in both pyridine and tropane alkaloid biosynthesis .

Reverse genetic approaches have not resulted in the cloning of a methylputrescine oxidase gene ( MPO ) .

However , we have used a homology-based approach to clone a full-length tobacco MPO1 cDNA .

The MPO1 gene is part of a small multigene family comprised of approximately six members .

MPO1-like transcript levels increased in roots that were either deprived of auxin or treated with methyl jasmonic acid .

Similar to other known nicotine biosynthetic genes in domesticated tobacco , MPO1-like mRNA levels were lower in roots with the mutant a and b alleles .

The MPO1 protein was expressed in bacteria as a recombinant Thioredoxin-His(6)-MPO1 fusion protein .

The recombinant MPO1 protein utilized N-methylputrescine more efficiently than other diamines .

Therefore , the kinetic properties of the MPO1 enzyme may play an important role in determining the pyridine alkaloid profiles observed in tobacco roots .