Signalling molecules and blast pathogen attack activates rice   and   genes: A model illustrating components participating during defence/stress response

Agrawal, Ganesh Kumar; Rakwal, Randeep; Jwa, Nam‐Soo; Agrawal, Vishwanath Prasad

doi:10.1016/s0981-9428(01)01333-x

Cited by 126 publications

(90 citation statements)

References 35 publications

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“…Several reports have specifically suggested the involvement of ABA in the regulation of plant defenses (Agrawal et al, 2001;Jiang and Zhang, 2001;Anderson et al, 2004;Ameline-Torregrosa et al, 2006;Schmidt et al, 2008;Wang et al, 2012). Microarray analysis to study the effects of ABA on gene expression in Arabidopsis, rice, and sorghum (Sorghum bicolor) plants revealed that a set of defense-related genes are induced after treatment with the phytohormone (Seki et al, 2002;Rabbani et al, 2003;Buchanan et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Plant Defense Mechanisms Are Activated during Biotrophic and Necrotrophic Development of Colletotricum graminicola in Maize

et al. 2012

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Hemibiotrophic plant pathogens first establish a biotrophic interaction with the host plant and later switch to a destructive necrotrophic lifestyle. Studies of biotrophic pathogens have shown that they actively suppress plant defenses after an initial microbe-associated molecular pattern-triggered activation. In contrast, studies of the hemibiotrophs suggest that they do not suppress plant defenses during the biotrophic phase, indicating that while there are similarities between the biotrophic phase of hemibiotrophs and biotrophic pathogens, the two lifestyles are not analogous. We performed transcriptomic, histological, and biochemical studies of the early events during the infection of maize (Zea mays) with Colletotrichum graminicola, a model pathosystem for the study of hemibiotrophy. Time-course experiments revealed that mRNAs of several defense-related genes, reactive oxygen species, and antimicrobial compounds all begin to accumulate early in the infection process and continue to accumulate during the biotrophic stage. We also discovered the production of maize-derived vesicular bodies containing hydrogen peroxide targeting the fungal hyphae. We describe the fungal respiratory burst during host infection, paralleled by superoxide ion production in specific fungal cells during the transition from biotrophy to a necrotrophic lifestyle. We also identified several novel putative fungal effectors and studied their expression during anthracnose development in maize. Our results demonstrate a strong induction of defense mechanisms occurring in maize cells during C. graminicola infection, even during the biotrophic development of the pathogen. We hypothesize that the switch to necrotrophic growth enables the fungus to evade the effects of the plant immune system and allows for full fungal pathogenicity.

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Section: Discussionmentioning

confidence: 99%

Plant Defense Mechanisms Are Activated during Biotrophic and Necrotrophic Development of Colletotricum graminicola in Maize

et al. 2012

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“…To characterize rice root invasion by M. oryzae at the molecular level, we used well-established foliar defense genes. Three members of the pathogenesis-related (Kankanala et al, 2007) gene families PR1 and PR10 were selected that previously had been shown to display strong gene induction during leaf infection by M. oryzae (Midoh and Iwata, 1996;Agrawal et al, 2001;McGee et al, 2001). Furthermore, induction mirrored infection dynamics for the two PR10 genes RPR10a (equivalent to PBZ1, probenazole-induced) and RPR10b (Midoh and Iwata, 1996;McGee et al, 2001).…”

Section: Root Invasion By M Oryzae Is Accompanied By Suppression Of mentioning

confidence: 99%

Tissue-Adapted Invasion Strategies of the Rice Blast Fungus Magnaporthe oryzae

et al. 2010

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Magnaporthe oryzae causes rice blast, the most serious foliar fungal disease of cultivated rice (Oryza sativa). During hemibiotrophic leaf infection, the pathogen simultaneously combines biotrophic and necrotrophic growth. Here, we provide cytological and molecular evidence that, in contrast to leaf tissue infection, the fungus adopts a uniquely biotrophic infection strategy in roots for a prolonged period and spreads without causing a loss of host cell viability. Consistent with a biotrophic lifestyle, intracellularly growing hyphae of M. oryzae are surrounded by a plant-derived membrane. Global, temporal gene expression analysis used to monitor rice responses to progressive root infection revealed a rapid but transient induction of basal defense-related gene transcripts, indicating perception of the pathogen by the rice root. Early defense gene induction was followed by suppression at the onset of intracellular fungal growth, consistent with the biotrophic nature of root invasion. By contrast, during foliar infection, the vast majority of these transcripts continued to accumulate or increased in abundance. Furthermore, induction of necrotrophy-associated genes during early tissue penetration, previously observed in infected leaves, was not seen in roots. Collectively, our results not only report a global characterization of transcriptional root responses to a biotrophic fungal pathogen but also provide initial evidence for tissue-adapted fungal infection strategies.

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“…The authors hypothesized that elevated NCED transcript levels in vtc1 compensate for the decreased cofactor (AsA) availability, resulting in increased ABA biosynthesis (Pastori et al, 2003). ABA induces PR-1 in other plant species, such as rice (Oryza sativa; Agrawal et al, 2001).…”

Section: Ascorbate Deficiency In Vtc1 Is Associated With Promotion Ofmentioning

confidence: 99%

The Timing of Senescence and Response to Pathogens Is Altered in the Ascorbate-Deficient Arabidopsis Mutant vitamin c-1

et al. 2004

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The ozone-sensitive Arabidopsis mutant vitamin c-1 (vtc1) is deficient in l-ascorbic acid (AsA) due to a mutation in GDP-Man pyrophosphorylase (Conklin et al., 1999), an enzyme involved in the AsA biosynthetic pathway (Smirnoff et al., 2001). In this study, the physiology of this AsA deficiency was initially investigated in response to biotic (virulent pathogens) stress and subsequently with regards to the onset of senescence. Infection with either virulent Pseudomonas syringae or Peronospora parasitica resulted in largely reduced bacterial and hyphal growth in the vtc1 mutant in comparison to the wild type. When vitamin c-2 (vtc2), another AsA-deficient mutant, was challenged with P. parasitica, growth of the fungus was also reduced, indicating that the two AsA-deficient mutants are more resistant to these pathogens. Induction of pathogenesis-related proteins PR-1 and PR-5 is significantly higher in vtc1 than in the wild type when challenged with virulent P. syringae. In addition, the vtc1 mutant exhibits elevated levels of some senescence-associated gene (SAG) transcripts as well as heightened salicylic acid levels. Presumably, therefore, low AsA is causing vtc1 to enter at least some stage(s) of senescence prematurely with an accompanying increase in salicylic acid levels that results in a faster induction of defense responses.

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Signalling molecules and blast pathogen attack activates rice and genes: A model illustrating components participating during defence/stress response

Cited by 126 publications

References 35 publications

Plant Defense Mechanisms Are Activated during Biotrophic and Necrotrophic Development of Colletotricum graminicola in Maize

Plant Defense Mechanisms Are Activated during Biotrophic and Necrotrophic Development of Colletotricum graminicola in Maize

Tissue-Adapted Invasion Strategies of the Rice Blast Fungus Magnaporthe oryzae

The Timing of Senescence and Response to Pathogens Is Altered in the Ascorbate-Deficient Arabidopsis Mutant vitamin c-1

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