Analysis of in planta Expressed Orphan Genes in the Rice Blast Fungus Magnaporthe oryzae (original) (raw)
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BMC Genomics, 2009
Background Magnaporthe oryzae, rice blast fungus, is the most devastating pathogen of rice. It has emerged as a model phytopathogen for the study of host-pathogen interactions. A large body of data has been generated on different aspects of biology of this fungus and on host-pathogen interactions. However, most of the data is scattered and is not available as a single resource for researchers in this field. Description Genomic Resources of Magnaporthe oyzae (GROMO), is a specialized, and comprehensive database for rice blast fungus, integrating information from several resources. GROMO contains information on genomic sequence, mutants available, gene expression, localization of proteins obtained from a variety of repositories, as primary data. In addition, prediction of domains, pathways, protein-protein interactions, sumolyation sites and biochemical properties that were obtained after computational analysis of protein sequences have also been included as derived data. This databas...
Molecular Plant-Microbe Interactions
The rice blast (fungal pathogen: Magnaporthe oryzae and host: Oryza sativa) is one of the most important model pathosystems for understanding plant–microbe interactions. Although both genome sequences were published as the first cases of pathogen and host, only a few in planta transcriptome data during infection are available. Due to technical difficulties, previously reported fungal transcriptome data are not highly qualified to comprehensively profile the expression of fungal genes during infection. Here, we report the high-quality transcriptomes of M. oryzae and rice during infection using a sheath infection-based RNA sequencing approach. This comprehensive expression profiling of the fungal pathogen and its host will provide a better platform for understanding the plant–microbe interactions at the genomic level and serve as a valuable resource for the research community.
Identification of fungal ( Magnaporthe grisea ) stress-induced genes in wild rice ( Oryza minuta )
Plant Cell Reports, 2004
To identify fungal stress-related genes in wild rice, Oryza minuta, we constructed a subtracted library using suppression subtractive hybridization in combination with mirror orientation selection. DNA chips containing 960 randomly selected cDNA clones were applied by reverse Northern analysis to eliminate false positive clones from the library and to prescreen differentially expressed genes. In total, 377 cDNA clones were selected on the basis of their signal intensities and expression ratios. Sequence analyses of these 377 cDNA fragments revealed that 180 of them (47.7%) represented unique genes. Of these180 cDNAs, 89 clones (49.6%) showed significant homologies to previously known genes, while the remaining 91 did not match any known sequences. The putative functions of the 180 unique ESTs were categorized by aligning them with MIPS data. They were classified into seven different groups using microarray data-derived expression patterns and verified by Northern blotting.
PLoS pathogens, 2009
For successful colonization and further reproduction in host plants, pathogens need to overcome the innate defenses of the plant. We demonstrate that a novel pathogenicity gene, DES1, in Magnaporthe oryzae regulates counter-defenses against host basal resistance. The DES1 gene was identified by screening for pathogenicity-defective mutants in a T-DNA insertional mutant library. Bioinformatic analysis revealed that this gene encodes a serine-rich protein that has unknown biochemical properties, and its homologs are strictly conserved in filamentous Ascomycetes. Targeted gene deletion of DES1 had no apparent effect on developmental morphogenesis, including vegetative growth, conidial germination, appressorium formation, and appressorium-mediated penetration. Conidial size of the mutant became smaller than that of the wild type, but the mutant displayed no defects on cell wall integrity. The Deltades1 mutant was hypersensitive to exogenous oxidative stress and the activity and transcri...
mSystems, 2020
Plants “lose” resistance toward pathogens shortly after their widespread emergence in the field because plant pathogens mutate and adapt rapidly under resistance selection. Thus, the rapid evolution of pathogens is a serious threat to plant health. Extensive studies have evaluated natural pathogen populations to understand their evolutionary effects; however, the study of the dynamic processes of the mutation and adaptation of plant pathogens to host plants remains limited. Here, by performing an experimental evolution study, we found a bias in genetic variation toward noncoding regions and SPs in the rice blast fungus Magnaporthe oryzae , which explains the ability of the rice blast fungus to maintain high virulence variation to overcome rice resistance in the field.
Journal of Bacteriology & Mycology: Open Access, 2017
Magnaporthe grisea is the most devastating pathogen of rice in all over the world, and the principal model organism for elucidating the molecular source of fungal disease of plants. This study, we report the draft sequence of the M. grisea genome. Examination of the gene set facilitates an insight into the adaptations essential by a fungus to source disease. The genome encodes a huge and varied set of secreted proteins, with those defined by remarkable carbohydrate-binding domains. This fungus also possesses a prolonged family of G-protein-coupled receptors, numerous novel virulence-associated genes and huge suites of enzymes occupied in secondary metabolism. Consistent with a function in fungal pathogenesis, the expression of a number of these genes up regulated 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 colonel nature of this fungus imposed by widespread rice cultivation. The study will be helpful to describe phylogenetic relations, pathogenicity, and genome analysis, drug design against diseases caused by fungi and cDNA synthesis and amplification to desired targets.
The Plant Cell …, 2009
To subvert rice (Oryza sativa) host defenses, the devastating ascomycete fungus pathogen Magnaporthe oryzae produces a battery of effector molecules, including some with avirulence (AVR) activity, which are recognized by host resistance (R) proteins resulting in rapid and effective activation of innate immunity. To isolate novel avirulence genes from M. oryzae, we examined DNA polymorphisms of secreted protein genes predicted from the genome sequence of isolate 70-15 and looked for an association with AVR activity. This large-scale study found significantly more presence/absence polymorphisms than nucleotide polymorphisms among 1032 putative secreted protein genes. Nucleotide diversity of M. oryzae among 46 isolates of a worldwide collection was extremely low (u = 8.2 3 10 25 ), suggestive of recent pathogen dispersal. However, no association between DNA polymorphism and AVR was identified. Therefore, we used genome resequencing of Ina168, an M. oryzae isolate that contains nine AVR genes. Remarkably, a total of 1.68 Mb regions, comprising 316 candidate effector genes, were present in Ina168 but absent in the assembled sequence of isolate 70-15. Association analyses of these 316 genes revealed three novel AVR genes, AVR-Pia, AVR-Pii, and AVR-Pik/km/kp, corresponding to five previously known AVR genes, whose products are recognized inside rice cells possessing the cognate R genes. AVR-Pia and AVR-Pii have evolved by gene gain/loss processes, whereas AVR-Pik/km/kp has evolved by nucleotide substitutions and gene gain/loss.
PLANT PHYSIOLOGY, 2005
To better understand the molecular basis of the defense response against the rice blast fungus (Magnaporthe grisea), a large-scale expressed sequence tag (EST) sequencing approach was used to identify genes involved in the early infection stages in rice (Oryza sativa). Six cDNA libraries were constructed using infected leaf tissues harvested from 6 conditions: resistant, partially resistant, and susceptible reactions at both 6 and 24 h after inoculation. Two additional libraries were constructed using uninoculated leaves and leaves from the lesion mimic mutant spl11. A total of 68,920 ESTs were generated from 8 libraries. Clustering and assembly analyses resulted in 13,570 unique sequences from 10,934 contigs and 2,636 singletons. Gene function classification showed that 42% of the ESTs were predicted to have putative gene function. Comparison of the pathogen-challenged libraries with the uninoculated control library revealed an increase in the percentage of genes in the functional ...
Genome-wide functional analysis of pathogenicity genes in the rice blast fungus
Nature Genetics, 2007
Rapid translation of genome sequences into meaningful biological information hinges on the integration of multiple experimental and informatics methods into a cohesive platform. Despite the explosion in the number of genome sequences available 1 , such a platform does not exist for filamentous fungi. Here we present the development and application of a functional genomics and informatics platform for a model plant pathogenic fungus, Magnaporthe oryzae 2 . In total, we produced 21,070 mutants through large-scale insertional mutagenesis using Agrobacterium tumefaciensmediated transformation 3 . We used a high-throughput phenotype screening pipeline to detect disruption of seven phenotypes encompassing the fungal life cycle and identified the mutated gene and the nature of mutation for each mutant. Comparative analysis of phenotypes and genotypes of the mutants uncovered 202 new pathogenicity loci. Our findings demonstrate the effectiveness of our platform and provide new insights on the molecular basis of fungal pathogenesis. Our approach promises comprehensive functional genomics in filamentous fungi and beyond.