Signal Pathways and Appressorium Morphogenesis

Dean, Ralph A.

doi:10.1146/annurev.phyto.35.1.211

Cited by 249 publications

(173 citation statements)

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“…To be a successful plant pathogen, a fungus must undergo a series of morphological and physiological programmes 5 . During these developmental transitions, the pathogen also overcomes (or suppresses) the plant's innate immune system and perturbs host metabolism and cell signalling to favour fungal growth.…”

Section: Grisea Has a Family Of Novel G-protein-coupled Receptorsmentioning

confidence: 99%

“…Infections occur when fungal spores land and attach themselves to leaves using a special adhesive released from the tip of each spore 4 . The germinating spore develops an appressorium-a specialized infection cell-which generates enormous turgor pressure (up to 8 MPa) that ruptures the leaf cuticle, allowing invasion of the underlying leaf tissue 5,6 . Subsequent colonization of the leaf produces disease lesions from which the fungus sporulates and spreads to new plants.…”

mentioning

confidence: 99%

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The genome sequence of the rice blast fungus Magnaporthe grisea

Dean

Talbot

Ebbole

et al. 2005

Nature

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Magnaporthe grisea is the most destructive pathogen of rice worldwide and the principal model organism for elucidating the molecular basis of fungal disease of plants. Here, we report the draft sequence of the M. grisea genome. Analysis of the gene set provides an insight into the adaptations required by a fungus to cause disease. The genome encodes a large and diverse set of secreted proteins, including those defined by unusual carbohydrate-binding domains. This fungus also possesses an expanded family of G-protein-coupled receptors, several new virulence-associated genes and large suites of enzymes involved in secondary metabolism. Consistent with a role in fungal pathogenesis, the expression of several of these genes is upregulated during the early stages of infection-related development. The M. grisea genome has been subject to invasion and proliferation of active transposable elements, reflecting the clonal nature of this fungus imposed by widespread rice cultivation.Outbreaks of rice blast disease are a serious and recurrent problem in all rice-growing regions of the world, and the disease is extremely difficult to control 1,2 . Rice blast, caused by the fungus Magnaporthe grisea, is therefore a significant economic and humanitarian problem. It is estimated that each year enough rice is destroyed by rice blast disease to feed 60 million people 3 . The life cycle of the rice blast fungus is shown in Fig. 1. Infections occur when fungal spores land and attach themselves to leaves using a special adhesive released from the tip of each spore 4 . The germinating spore develops an appressorium-a specialized infection cell-which generates enormous turgor pressure (up to 8 MPa) that ruptures the leaf cuticle, allowing invasion of the underlying leaf tissue 5,6 . Subsequent colonization of the leaf produces disease lesions from which the fungus sporulates and spreads to new plants. When rice blast infects young rice seedlings, whole plants often die, whereas spread of the disease to the stems, nodes or panicle of older plants results in nearly total loss of the rice grain 2 . Different host-limited forms of M. grisea also infect a broad range of grass species including wheat, barley and millet. Recent reports have shown that the fungus has the capacity to infect plant roots 7 .Here we present our preliminary analysis of the draft genome sequence of M. grisea, which has emerged as a model system for understanding plant-microbe interactions because of both its economic significance and genetic tractability 1,2 . Acquisition of the M. grisea genome sequenceThe genome of a rice pathogenic strain of M. grisea, 70-15, was sequenced through a whole-genome shotgun approach. In all, greater than sevenfold sequence coverage was produced, and a summary of the principal genome sequence data is provided in Table 1 and Supplementary Table S1. The draft genome sequence consists of 2,273 sequence contigs longer than 2 kilobases (kb), ordered and orientated within 159 scaffolds. The total length of all sequence contigs is 38.8 mega...

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Section: Grisea Has a Family Of Novel G-protein-coupled Receptorsmentioning

confidence: 99%

mentioning

confidence: 99%

The genome sequence of the rice blast fungus Magnaporthe grisea

Dean

Talbot

Ebbole

et al. 2005

Nature

Self Cite

1,481

1,194

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show abstract

“…The released secondary messenger (DAG) activates protein kinase C(PKC) while IP3 triggers the release of Ca 2+ from storage and binds to calcium-dependent targets comprising calcium/calmodulin (CaM)-dependent protein phosphatase, calcineurin (Buchner 1995). These calcium-dependent proteins and PKC traverse the nucleus to activate downstream effectors and transcriptional factors through phosphorylation (Dean 1997). In M. oryzae , a calcineurin-dependent transcription factor, Mo CRZ 1, is required for normal vegetative growth, appressorium function and pathogenicity (Choi et al 2009).…”

Section: Signal Transducing Cascades Associated With Appressorium Formentioning

confidence: 99%

Regulatory network of genes associated with stimuli sensing, signal transduction and physiological transformation of appressorium inMagnaporthe oryzae

et al. 2018

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Rice blast caused by Magnaporthe oryzae is the most destructive disease affecting the rice production (Oryza sativa), with an average global loss of 10–30% per annum. Recent reports have indicated that the fungus also inflicts blast disease on wheat (Triticum aestivum) posing a serious threat to the wheat production. Due to its easily detected infectious process and manoeuvrable genetic manipulation, M. oryzae is considered a model organism for exploring the molecular mechanism underlying fungal pathogenicity during the pathogen–host interaction. M. oryzae utilises an infectious structure called appressorium to breach the host surface by generating high turgor pressure. The appressorium development is induced by physical and chemical cues which are coordinated by the highly conserved cAMP/PKA, MAPK and calcium signalling cascades. Genes involved in the appressorium development have been identified and well studied in M. oryzae, a summary of the working gene network linking stimuli sensing and physiological transformation of appressorium is needed. This review provides a comprehensive discussion regarding the regulatory networks underlying appressorium development with particular emphasis on sensing of appressorium inducing stimuli, signal transduction, transcriptional regulation and the corresponding developmental and physiological responses. We also discussed the crosstalk and interaction of various pathways during the appressorium development.

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“…The infection of rice blast occur when fungal spores land and attach themselves to leaves using a special adhesive released from the tip of each spore (Hamer, Howard, Chumley, & Valent, 1988). The germinating spore develops an appressorium, a specialized infection cell which generates enormous turgor pressure (up to 8MPa) that ruptures the leaf cuticle, allowing invasion of the underlying leaf tissue (Dean, 1997;Hamer et al, 1988). Subsequent colonization of the leaf produces disease lesions from which the fungus sporulates and spreads to new plants.…”

Section: Introductionmentioning

confidence: 99%

Untitled

2014

Plant Sci Today

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Blast disease caused by fungal pathogen Magnaporthe oryzae is the most severe disease of rice (Oryza sativa L). On an estimate it annually destroys rice, which can feed around 60 million people. Keeping in view the importance of the disease, various management strategies like controlled use of nitrogen fertilizers, application of silica and flooding of paddy fields are the practices in use to reduce the rice blast since long time. Improved chemical methods include utilization of copper fungicides, organomercuric and organophosphorus compounds. Some antibiotics e.g., Blasticidin S and Kasugamycin and many systemic and site specific fungicides including melanin biosynthesis inhibitors and plant activators were also utilized effectively for blast management. In the recent years leaf extracts of tulsi and bael have been found effective. Due to the highly variable nature of M. oryzae, exploitation of durable host resistance has remained a challenging job for plant pathologists and breeders. Lots of efforts have been made worldwide to study the variability in the pathogen and to find out the resistance sources. To date approximately 100 R genes for blast resistance have been mapped and 20 of these genes have been cloned in rice. Now, scientists are looking forward to develop durable resistant varieties through pyramiding of quantitative trait loci and major genes. Among the biocontrol agents, different strains of Bacillus spp. and Streptomyces sindeneusis are in use. The availability of rice and M. oryzae genome sequence data are facilitating blast resistance management program to new paradigms which includes isolation and characterization of R and Avr genes, development of noble fungicides, transformed bioagents, transgenic rice and durable resistance.

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Signal Pathways and Appressorium Morphogenesis

Cited by 249 publications

References 132 publications

The genome sequence of the rice blast fungus Magnaporthe grisea

The genome sequence of the rice blast fungus Magnaporthe grisea

Regulatory network of genes associated with stimuli sensing, signal transduction and physiological transformation of appressorium inMagnaporthe oryzae

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