Genome assisted molecular typing and pathotyping of rice blast pathogen, Magnaporthe oryzae, reveals a genetically homogenous population with high virulence diversity

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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Two Novel Transcriptional Regulators Are Essential for Infection-related Morphogenesis and Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

PLoS Pathogens ◽

10.1371/journal.ppat.1002385 ◽

2011 ◽

Vol 7 (12) ◽

pp. e1002385 ◽

Cited By ~ 44

Author(s):

Xia Yan ◽

Ya Li ◽

Xiaofeng Yue ◽

Congcong Wang ◽

Yawei Que ◽

...

Keyword(s):

Magnaporthe Oryzae ◽

Rice Blast ◽

Transcriptional Regulators ◽

Rice Blast Fungus ◽

Blast Fungus

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Septin-Mediated Plant Cell Invasion by the Rice Blast Fungus, Magnaporthe oryzae

Science ◽

10.1126/science.1222934 ◽

2012 ◽

Vol 336 (6088) ◽

pp. 1590-1595 ◽

Cited By ~ 174

Author(s):

Y. F. Dagdas ◽

K. Yoshino ◽

G. Dagdas ◽

L. S. Ryder ◽

E. Bielska ◽

...

Keyword(s):

Plant Cell ◽

Cell Invasion ◽

Magnaporthe Oryzae ◽

Rice Blast ◽

Rice Blast Fungus ◽

Blast Fungus

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The MoT3 assay does not distinguish between Magnaporthe oryzae wheat and rice blast isolates from Bangladesh

10.1101/345215 ◽

2018 ◽

Author(s):

Dipali Rani Gupta ◽

Claudia Sarai Reyes Avila ◽

Joe Win ◽

Darren M. Soares ◽

Lauren S. Ryder ◽

...

Keyword(s):

Magnaporthe Oryzae ◽

Rice Blast ◽

Dna Amplification ◽

Diagnostic Tools ◽

Diagnostic Assay ◽

Asian Countries ◽

Wheat Blast ◽

New Hosts ◽

Grass Hosts ◽

The Uk

ABSTRACTThe blast fungus Magnaporthe oryzae is comprised of lineages that exhibit varying degrees of specificity on about 50 grass hosts, including rice, wheat and barley. Reliable diagnostic tools are essential given that the pathogen has a propensity to jump to new hosts and spread to new geographic regions. Of particular concern is wheat blast, which has suddenly appeared in Bangladesh in 2016 before spreading to neighboring India. In these Asian countries, wheat blast strains are now co-occurring with the destructive rice blast pathogen raising the possibility of genetic exchange between these destructive pathogens. We assessed the recently described MoT3 diagnostic assay and found that it did not distinguish between wheat and rice blast isolates from Bangladesh. The assay is based on primers matching the WB12 sequence corresponding to a fragment of the M. oryzae MGG_02337 gene annotated as a short chain dehydrogenase. These primers could not reliably distinguish between wheat and rice blast isolates from Bangladesh based on DNA amplification experiments performed in separate laboratories in Bangladesh and in the UK. In addition, comparative genomics of the WB12 sequence revealed a complex underlying genetic structure with related sequences across M. oryzae strains and in both rice and wheat blast isolates. We, therefore, caution against the indiscriminate use of this assay to identify wheat blast.

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Osa-miR162a balances rice yield and resistance to Magnaporthe oryzae

10.21203/rs.2.22473/v1 ◽

2020 ◽

Author(s):

Xu-Pu Li ◽

Xiao-Chun Ma ◽

He Wang ◽

Yong Zhu ◽

Xin-Xian Liu ◽

...

Keyword(s):

Magnaporthe Oryzae ◽

Rice Blast ◽

Rice Yield ◽

Blast Resistance ◽

Blast Disease ◽

Mirna Biogenesis ◽

Trade Off ◽

Rice Blast Resistance ◽

Defense Related Gene ◽

Transgenic Lines

Abstract MicroRNAs (miRNAs) play essential roles in rice immunity against Magnaporthe oryzae, the causative agent of rice blast disease. Osa-miR162a targets Dicer-like 1 (DCL1) genes, which play vital roles in miRNA biogenesis and act as negative regulators in rice immunity. Here we demonstrate that Osa-miR162a improves rice immunity against M. oryzae and balances the trade-off between rice yield and resistance. Overexpression of Osa-miR162a compromises rice susceptibility to M. oryzae accompanying enhanced induction of defense-related genes and accumulation of hydrogen peroxide (H2O2). In contrast, blocking miR162 by overexpressing a target mimic of miR162 enhances susceptibility to blast fungus associating with compromised induction of defense-related gene expression and H2O2 accumulation. Moreover, the transgenic lines overexpressing Osa-miR162a display decreased seed setting rate resulting in reduced yield per plant, whereas blocking miR162 leads to an increased number of grains per panicle, resulting in increased yield per plant. Altered accumulation of miR162 had limited impact on the expression of OsDCL1. Together, our results indicate that Osa-miR162a improves rice blast resistance and plays a role in the balance of trade-off between resistance and yield.

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Lessons in effector and NLR biology of plant-microbe systems

10.1101/171223 ◽

2017 ◽

Cited By ~ 2

Author(s):

Aleksandra Białas ◽

Erin K. Zess ◽

Juan Carlos De la Concepcion ◽

Marina Franceschetti ◽

Helen G. Pennington ◽

...

Keyword(s):

Plant Physiology ◽

Magnaporthe Oryzae ◽

Rice Blast ◽

Molecular Mechanisms ◽

Rice Blast Fungus ◽

Leucine Rich Repeat ◽

Nucleotide Binding Domain ◽

Immune Receptors ◽

Microbe Interactions ◽

Host Infection

A diversity of plant-associated organisms secrete effectors—proteins and metabolites that modulate plant physiology to favor host infection and colonization. However, effectors can also activate plant immune receptors, notably nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins, enabling plants to fight off invading organisms. This interplay between effectors, their host targets, and the matching immune receptors is shaped by intricate molecular mechanisms and exceptionally dynamic coevolution. In this article, we focus on three effectors, AVR-Pik, AVR-Pia, and AVR-Pii, from the rice blast fungus Magnaporthe oryzae (syn. Pyricularia oryzae), and their corresponding rice NLR immune receptors, Pik, Pia, and Pii, to highlight general concepts of plant-microbe interactions. We draw 12 lessons in effector and NLR biology that have emerged from studying these three little effectors and are broadly applicable to other plant-microbe systems.

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