Abstract Glutathione is a major cellular thiol that maintained in the reduced state by glutathione reductase (GR), which encoded two genes Arabidopsis (Arabidopsis thaliana; GR1 and GR2). This study addressed role of hydrogen peroxide (H2O2) responses through combined genetic, transcriptomic, redox profiling approach. To identify potential changes status H2O2 signaling, gr1 mutants, show constitutive increase oxidized (GSSG), were compared with catalase-deficient background (cat2), GSSG...

Plant UDP-Glc:phenylpropanoid glucosyltransferases (UGTs) catalyze the transfer of Glc from UDP-Glc to numerous substrates and regulate activity compounds that play important roles in plant defense against pathogens. We previously characterized two tobacco salicylic acid– pathogen-inducible UGTs (TOGTs) act very efficiently on hydroxycoumarin scopoletin hydroxycinnamic acids. To identify physiological these defense, we generated TOGT-depleted plants by antisense expression. After inoculation...

While it is well established that reactive oxygen species can induce cell death, intracellularly generated oxidative stress does not lesions in the Arabidopsis (Arabidopsis thaliana) photorespiratory mutant cat2 when plants are grown short days (SD). One interpretation of this observation a function necessary to couple peroxisomal hydrogen peroxide (H(2)O(2))-triggered death only operative long (LD). Like lesion formation, pathogenesis-related genes and camalexin were induced LD, despite...

The genome sequencing of Arabidopsis (Arabidopsis thaliana) has revealed that secondary metabolism plant glycosyltransferases (UGTs) are encoded by an unexpectedly large multigenic family 120 members. Very little is known about their actual function in planta, particular during pathogen interactions. Among them, members the group D interest since they related to UGTs involved stress-inducible responses other species. We provide here a detailed analysis expression profiles this following...

We have analyzed the spatial and temporal expression of defense responses induced in attached tobacco leaves treated with a Phytophthora megasperma glycoprotein that was previously shown to be an efficient elicitor hypersensitive reaction. The infiltrated tissue (zone 1), surrounding 2), which is 5 mm width, at distance >2 cm from zone 2 3) were separately. Cell death occurred only 1 completed by 14 h. Defense gene zones striking differential patterns, but not 3. There rapid (1 4 h)...

The hypersensitive response (HR) is a programmed cell death that commonly associated with plant disease resistance. A novel lesion mimic mutant, vad1 (for vascular death1), exhibits light conditional appearance of propagative HR-like lesions along the system was identified. Lesion formation expression defense genes, production high levels salicylic acid (SA), and increased resistance to virulent avirulent strains Pseudomonas syringae pv tomato. Analyses progeny from crosses between plants...

Abstract Salicylic acid (SA) is a key endogenous component of local and systemic disease resistance in plants. In this study, we investigated the role benzoic (BA) as precursor SA biosynthesis tobacco (Nicotiana tabacum cv Samsun NN) plants undergoing hypersensitive response following infection with mosaic virus or cell suspensions elicited β-megaspermin, an elicitor from Phytophthora megasperma. We found small pool conjugated BA healthy leaves untreated tobacco, whereas free levels were...

Although it is a crucial cellular process required for both normal development and to face stress conditions, the control of programmed cell death in plants not fully understood. We previously reported isolation ATXR5 ATXR6, two PCNA-binding proteins that could be involved regulation cycle or death. A yeast two-hybrid screen using as bait captured AtIPS1, an enzyme which catalyses committed step myo-inositol (MI) biosynthesis. atips1 mutants form spontaneous lesions on leaves, raising...

Cytosolic NADP-dependent isocitrate dehydrogenase (cICDH) produces 2-oxoglutarate (2-OG) and NADPH, is encoded by a single gene in Arabidopsis thaliana. Three allelic lines carrying T-DNA insertions this showed less than 10% extractable leaf ICDH activity, but only relatively small decreases growth compared to wild-type Col0. Metabolite profiling gas chromatography–time of flight–mass spectrometry (GC–TOF–MS) high-performance liquid chromatography (HPLC) revealed that loss cICDH function...

Abstract Siderophores (ferric ion chelators) are secreted by organisms in response to iron deficiency. The pathogenic enterobacterium Erwinia chrysanthemi produces two siderophores, achromobactin and chrysobactin (CB), which required for systemic dissemination host plants. Previous studies have shown that CB is produced planta can trigger the up-regulation of plant ferritin gene AtFER1. To further investigate function during pathogenesis, we analyzed its effect Arabidopsis (Arabidopsis...

Abstract Phosphite (Phi), a phloem-mobile oxyanion of phosphorous acid (H3PO3), protects plants against diseases caused by oomycetes. Its mode action is unclear, as evidence indicates both direct antibiotic effects on pathogens well inhibition through enhanced plant defense responses, and its target(s) in the unknown. Here, we demonstrate that biotrophic oomycete Hyaloperonospora arabidopsidis (Hpa) exhibits an unusual biphasic dose-dependent response to Phi after inoculation Arabidopsis...

Plant small-molecule UDP-glycosyltransferases (UGT) glycosylate a vast number of endogenous substances but also act in detoxification metabolites produced by plant-pathogenic microorganisms. The ability to inactivate the Fusarium graminearum mycotoxin deoxynivalenol (DON) into DON-3-O-glucoside is crucial for resistance cereals. We analyzed UGT gene family monocot model species Brachypodium distachyon and functionally characterized two clusters containing putative orthologs previously...

Fusarium head blight (FHB) is a cereal disease caused by graminearum, fungus able to produce type B trichothecenes on cereals, including deoxynivalenol (DON), which harmful for humans and animals. Resistance FHB quantitative, the mechanisms underlying resistance are poorly understood. has been related ability conjugate DON into glucosylated form, deoxynivalenol-3-O-glucose (D3G), secondary metabolism UDP-glucosyltransferases (UGTs). However, functional analyses have never performed within...

Two tobacco genes ( TOGT ) with homology to glucosyltransferase known be induced by salicylic acid (SA) also responded rapidly a fungal elicitor or an avirulent pathogen. SA, although efficient inducer, was shown not essential in the signal transduction pathway regulating gene expression during resistance response. Recombinant proteins produced Escherichia coli exhibited low, but significant, activity towards very high hydroxycoumarins and hydroxycinnamic acids, glucose esters being...

Expression of tobacco class I (CAT1) and II (CAT2) catalases was analyzed in leaves reacting hypersensitively to mosaic virus (TMV) or a fungal glycoprotein elicitor. In TMV-infected plants, Cat1 transcript levels declined rapidly while Cat2 transcripts accumulated strongly. The spatial temporal changes catalase transcripts, proteins, activity during the hypersensitive reaction (HR) were further investigated infiltrated with Two functionally different zones discriminated: tissue which cells...

A 32 kDa glycoprotein whose effects in tobacco and other Nicotianae mimic a typical hypersensitive response, was isolated from Phytophthora megasperma. Infiltration of few nanograms the protein into leaves caused formation lesions that closely resemble response lesions. Transcripts genes encoding enzymes phenylpropanoid sesquiterpenoid pathways accumulated rapidly after elicitor application followed by salicylic acid production. Cellular damage, restricted to infiltrated zone, occurred only...

Secondary metabolism plant glycosyltransferases (UGTs) ensure conjugation of sugar moieties to secondary metabolites (SMs) and glycosylation contributes the great diversity, reactivity regulation SMs. UGT73B3 UGT73B5, two UGTs Arabidopsis thaliana (Arabidopsis), are involved in hypersensitive response (HR) avirulent bacteria Pseudomonas syringae pv. tomato (Pst-AvrRpm1), but their function planta is unknown. Here, we report that ugt73b3, ugt73b5 ugt73b3 T-DNA insertion mutants exhibited an...

Fusarium Head Blight (FHB) caused primarily by graminearum (Fg) is one of the major diseases small-grain cereals including bread wheat. This disease both reduces yields and causes quality losses due to production deoxynivalenol (DON), type B trichothecene mycotoxin. DON has been described as a virulence factor enabling efficient colonization spikes fungus in wheat, but its precise role during infection process still elusive. Brachypodium distachyon (Bd) model cereal species which shown be...

Abstract Background Partial resistance to plant pathogens is extensively used in breeding programs since it could contribute durability. often builds up during development and confers quantitative usually broad-spectrum resistance. However, very little known on the mechanisms underlying partial explained by poorly effective induction of defense systems. By exploring rice natural diversity, we asked whether expression systems before infection explain towards major fungal pathogen Magnaporthe...

Secondary metabolites (SMs) play key roles in pathogen responses, although knowledge of their precise functions is limited by insufficient characterization spatial response. The present study addressed this issue Arabidopsis leaves non-targeted and targeted metabolite profiling Pseudomonas syringae pv. tomato (Pst-AvrRpm1) infected adjacent uninfected leaf tissues. While overlap was observed between areas, the profiles these regions differed quantitatively clustering analysis underscores a...

Piperonylic acid (PA) is a natural molecule bearing methylenedioxy function that closely mimics the structure of trans-cinnamic acid. The CYP73A subfamily plant P450s catalyzes 4-hydroxylation, second step general phenylpropanoid pathway. We show when incubated in vitro with yeast-expressed CYP73A1, PA behaves as potent mechanism-based and quasi-irreversible inactivator trans-cinnamate 4-hydroxylase. Inactivation requires NADPH, time dependent saturable (KI = 17 &mgr;M, kinact 0.064 min-1),...