Genetic Structure of the Rice Blast Pathogen (Magnaporthe oryzae) over a Decade in North Central California Rice Fields

A previous study of the diversity and population structure of the rice blast fungus, Magnaporthe oryzae, over a 20-year period in Korea, found novel fingerprint haplotypes each year, and the authors hypothesized that populations might experience annual bottlenecks. Based on this model, we predicted that M. oryzae populations would have little or no genetic differentiation among geographic regions because rice blast is commonly found throughout Korea each year and M. oryzae would have to disperse from small populations surviving annually between rice crops. To test this hypothesis, we sampled M. oryzae from rice fields in eight provinces in Korea in a single year (1999). In four provinces, we sampled from a set of rice cultivars commonly grown in commercial fields (group I); because of low disease incidence in four other provinces, we could not sample from commercial fields and instead sampled from scouting plots of different cultivars set up for detecting new pathotypes of M. oryzae (group II). All isolates were genotyped with DNA fingerprint probes MGR586 and MAGGY, a telomere-linked gene family member TLH1, the PWL2 host specificity gene and mating type. Fingerprint haplotypes clustered into two distinct lineages corresponding to the two sets of cultivars (groups I and II), with haplotype similarities of 71% between lineages and >76% within lineages. Isolates from the same cultivar within group I were genetically differentiated among locations, and isolates within the same location were differentiated among cultivars. Differentiation for TLH1 and PWL2 was significant (P < 0.03), but not as strong as for fingerprint markers. Similar analyses were not possible among group II isolates because too few isolates were available from any one cultivar. All isolates were in the same mating type, Mat1-1, ruling out sexual reproduction as a source of novel haplotypes. When the 1999 samples were compared with the historical samples from the previous study, haplotypes of group I formed a separate cluster, while those of group II clustered with haplotypes from the historical sample. Altogether, geographic subdivision, monomorphism of mating type, and correlation of haplotypes to sets of cultivars are not consistent with the hypothesis of repeated turnover of haplotypes. Instead, the previous correlations of haplotypes to year might have been caused by inadequate sampling of haplotypes each year, highlighting the need for studies of population genetics to be conducted with systematic samples collected to address specific questions.

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Hot spots for diversity of Magnaporthe oryzae physiological races in irrigated rice fields in Brazil

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2010000300004 ◽

2010 ◽

Vol 45 (3) ◽

pp. 252-260 ◽

Cited By ~ 5

Author(s):

Justino José Dias Neto ◽

Gil Rodrigues dos Santos ◽

Liamar Maria dos Anjos ◽

Paulo Hideo Nakano Rangel ◽

Marcio Elias Ferreira

Keyword(s):

Magnaporthe Oryzae ◽

Rice Blast ◽

Blast Resistance ◽

River Valley ◽

Rice Fields ◽

Breeding Programs ◽

Irrigated Rice ◽

Small Areas ◽

Araguaia River ◽

Resistance Breakdown

The objective of this work was to evaluate the Magnaporthe oryzae pathotype diversity in new commercial irrigated rice fields in the Araguaia River Valley, state of Tocantins, Brazil. The causal agent of rice blast has heavily affected rice production in the region. Despite the efforts of breeding programs, blast resistance breakdown has been recorded shortly after the release of new resistant cultivars developed for the region. Among the causes of resistance breakage is the capacity of the fungus to rapidly develop new pathotypes. A sample of 479 M. oryzae monosporic isolates was obtained and tested using the international rice blast differential set. Isolate collections were made in small areas designed as trap nurseries and in scattered sites in their vicinity. Analysis of 250 M. oryzae isolates from three trap nurseries indicated the presence of 45 international M. oryzae races belonging to seven pathotype groups (IA-IG). In the isolates tested, 61 M. oryzae pathotypes belonging to all but the IH group were detected. The new areas of irrigated rice in the Araguaia River Valley have the highest diversity of M. oryzae pathotypes reported so far in Brazil.

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Both MAT1-1 and MAT 1-2 idiomorphs present in rice blast populations (Magnaporthe oryzae) collected in rice fields in northern Brazil

New Disease Reports ◽

10.5197/j.2044-0588.2019.040.003 ◽

2019 ◽

Vol 40 ◽

pp. 3

Author(s):

L.S. D´Ávila ◽

M.C.C. De Filippi ◽

A.C. Café-Filho

Keyword(s):

Magnaporthe Oryzae ◽

Rice Blast ◽

Rice Fields ◽

Northern Brazil

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Spartial Variation in Physicochemical Characteristics of Wetland Rice Fields Mosquito Larval Habitats in Minna, North Central Nigeria

International Conference on Agricultural, Ecological and Medical Sciences (AEMS-2015) Feb. 10-11, 2015 Penang (Malaysia) ◽

10.15242/iicbe.c0215116 ◽

2015 ◽

Keyword(s):

Physicochemical Characteristics ◽

Rice Fields ◽

Wetland Rice ◽

North Central ◽

Larval Habitats

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Investigating the cell and developmental biology of plant infection by the rice blast fungus Magnaporthe oryzae

Fungal Genetics and Biology ◽

10.1016/j.fgb.2021.103562 ◽

2021 ◽

pp. 103562

Author(s):

Alice Bisola Eseola ◽

Lauren S. Ryder ◽

Míriam Osés-Ruiz ◽

Kim Findlay ◽

Xia Yan ◽

...

Keyword(s):

Developmental Biology ◽

Magnaporthe Oryzae ◽

Rice Blast ◽

Rice Blast Fungus ◽

Plant Infection ◽

Blast Fungus

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Understanding Rice-Magnaporthe Oryzae Interaction in Resistant and Susceptible Cultivars of Rice under Panicle Blast Infection Using a Time-Course Transcriptome Analysis

Genes ◽

10.3390/genes12020301 ◽

2021 ◽

Vol 12 (2) ◽

pp. 301

Author(s):

Vishesh Kumar ◽

Priyanka Jain ◽

Sureshkumar Venkadesan ◽

Suhas Gorakh Karkute ◽

Jyotika Bhati ◽

...

Keyword(s):

Cell Wall ◽

Secondary Metabolites ◽

Magnaporthe Oryzae ◽

Transcriptome Analysis ◽

Hormonal Regulation ◽

Rice Blast ◽

Blast Resistance ◽

Differentially Expressed ◽

Specific Response ◽

Panicle Blast

Rice blast is a global threat to food security with up to 50% yield losses. Panicle blast is a more severe form of rice blast and the response of rice plant to leaf and panicle blast is distinct in different genotypes. To understand the specific response of rice in panicle blast, transcriptome analysis of blast resistant cultivar Tetep, and susceptible cultivar HP2216 was carried out using RNA-Seq approach after 48, 72 and 96 h of infection with Magnaporthe oryzae along with mock inoculation. Transcriptome data analysis of infected panicle tissues revealed that 3553 genes differentially expressed in HP2216 and 2491 genes in Tetep, which must be the responsible factor behind the differential disease response. The defense responsive genes are involved mainly in defense pathways namely, hormonal regulation, synthesis of reactive oxygen species, secondary metabolites and cell wall modification. The common differentially expressed genes in both the cultivars were defense responsive transcription factors, NBS-LRR genes, kinases, pathogenesis related genes and peroxidases. In Tetep, cell wall strengthening pathway represented by PMR5, dirigent, tubulin, cell wall proteins, chitinases, and proteases was found to be specifically enriched. Additionally, many novel genes having DOMON, VWF, and PCaP1 domains which are specific to cell membrane were highly expressed only in Tetep post infection, suggesting their role in panicle blast resistance. Thus, our study shows that panicle blast resistance is a complex phenomenon contributed by early defense response through ROS production and detoxification, MAPK and LRR signaling, accumulation of antimicrobial compounds and secondary metabolites, and cell wall strengthening to prevent the entry and spread of the fungi. The present investigation provided valuable candidate genes that can unravel the mechanisms of panicle blast resistance and help in the rice blast breeding program.

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Tanzawaic acids I–L: Four new polyketides from Penicillium sp. IBWF104-06

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.10.20 ◽

2014 ◽

Vol 10 ◽

pp. 251-258 ◽

Cited By ~ 8

Author(s):

Louis P Sandjo ◽

Eckhard Thines ◽

Till Opatz ◽

Anja Schüffler

Keyword(s):

Soil Sample ◽

Magnaporthe Oryzae ◽

Rice Blast ◽

Rice Blast Fungus ◽

Fungal Strain ◽

Conidial Germination ◽

Penicillium Sp ◽

Culture Filtrates ◽

Blast Fungus ◽

New Compounds

Four new polyketides have been identified in culture filtrates of the fungal strain Penicillium sp. IBWF104-06 isolated from a soil sample. They are structurally based on the same trans-decalinpentanoic acid skeleton as tanzawaic acids A–H. One of the new compounds was found to inhibit the conidial germination in the rice blast fungus Magnaporthe oryzae at concentrations of 25 μg/mL.

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A Homeobox Gene Is Essential for Conidiogenesis of the Rice Blast Fungus Magnaporthe oryzae

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-4-0366 ◽

2010 ◽

Vol 23 (4) ◽

pp. 366-375 ◽

Cited By ~ 52

Author(s):

Wende Liu ◽

Shiyong Xie ◽

Xinhua Zhao ◽

Xin Chen ◽

Wenhui Zheng ◽

...

Keyword(s):

Magnaporthe Oryzae ◽

Rice Blast ◽

Homeobox Gene ◽

Gene Replacement ◽

Fungal Genome ◽

Protein Signaling ◽

Homeodomain Proteins ◽

Conidial Production ◽

Targeted Gene Replacement ◽

Severity Of The Disease

Magnaporthe oryzae starts its infection by the attachment of pyriform conidia on rice tissues, and severity of the disease epidemic is proportional to the quantity of conidia produced in the rice blast lesions. However, the mechanism of conidial production is not well understood. Homeodomain proteins play critical roles in regulating various growth and developmental processes in fungi and other eukaryotes. Through targeted gene replacement, we find that deletion of HTF1, one of seven homeobox genes in the fungal genome, does not affect mycelial growth but causes total defect of conidial production. Further observation revealed that the Δhtf1 mutant produces significantly more conidiophores, which curve slightly near the tip but could not develop sterigmata-like structures. Although the Δhtf1 mutant fails to form conidia, it could still develop melanized appressoria from hyphal tips and infect plants. The expression level of HTF1 is significantly reduced in the Δmgb1 G-β and ΔcpkA deletion mutant, and the ACR1 but not CON7 gene that encodes transcription factor required for normal conidiogenesis is significantly downregulated in the Δhtf1 mutant. These data suggest that the HTF1 gene is essential for conidiogenesis, and may be functionally related to the trimeric G-protein signaling and other transcriptional regulators that are known to be important for conidiation in M. oryzae.

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