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

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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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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Functional complementation of rice blast resistance gene Pi-k h (Pi54) conferring resistance to diverse strains of Magnaporthe oryzae

Journal of Plant Biochemistry and Biotechnology ◽

10.1007/s13562-010-0026-1 ◽

2011 ◽

Vol 20 (1) ◽

pp. 55-65 ◽

Cited By ~ 50

Author(s):

Amit Kumar Rai ◽

Satya Pal Kumar ◽

Santosh Kumar Gupta ◽

Naveen Gautam ◽

Nagendera Kumar Singh ◽

...

Keyword(s):

Resistance Gene ◽

Magnaporthe Oryzae ◽

Rice Blast ◽

Blast Resistance ◽

Functional Complementation ◽

Rice Blast Resistance ◽

Blast Resistance Gene

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Genotyping-by-Sequencing-Based Genetic Analysis of African Rice Cultivars and Association Mapping of Blast Resistance Genes Against Magnaporthe oryzae Populations in Africa

Phytopathology ◽

10.1094/phyto-12-16-0421-r ◽

2017 ◽

Vol 107 (9) ◽

pp. 1039-1046 ◽

Cited By ~ 4

Author(s):

Emmanuel M. Mgonja ◽

Chan Ho Park ◽

Houxiang Kang ◽

Elias G. Balimponya ◽

Stephen Opiyo ◽

...

Keyword(s):

Genetic Diversity ◽

Association Mapping ◽

Magnaporthe Oryzae ◽

Rice Blast ◽

Blast Resistance ◽

Genotyping By Sequencing ◽

Rice Breeding ◽

Rice Cultivars ◽

R Genes ◽

African Rice

Understanding the genetic diversity of rice germplasm is important for the sustainable use of genetic materials in rice breeding and production. Africa is rich in rice genetic resources that can be utilized to boost rice productivity on the continent. A major constraint to rice production in Africa is rice blast, caused by the hemibiotrophic fungal pathogen Magnaporthe oryzae. In this report, we present the results of a genotyping-by-sequencing (GBS)-based diversity analysis of 190 African rice cultivars and an association mapping of blast resistance (R) genes and quantitative trait loci (QTLs). The 190 African cultivars were clustered into three groups based on the 184K single nucleotide polymorphisms generated by GBS. We inoculated the rice cultivars with six African M. oryzae isolates. Association mapping identified 25 genomic regions associated with blast resistance (RABRs) in the rice genome. Moreover, PCR analysis indicated that RABR_23 is associated with the Pi-ta gene on chromosome 12. Our study demonstrates that the combination of GBS-based genetic diversity population analysis and association mapping is effective in identifying rice blast R genes/QTLs that contribute to resistance against African populations of M. oryzae. The identified markers linked to the RABRs and 14 highly resistant cultivars in this study will be useful for rice breeding in Africa.

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Improvement of rice blast resistance by developing monogenic lines, two-gene pyramids and three-gene pyramid through MAS

Rice ◽

10.1186/s12284-019-0336-4 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Wuming Xiao ◽

Qiyun Yang ◽

Ming Huang ◽

Tao Guo ◽

Yongzhu Liu ◽

...

Keyword(s):

Rice Blast ◽

Agronomic Traits ◽

Blast Resistance ◽

Field Conditions ◽

Blast Disease ◽

Recurrent Parent ◽

Panicle Blast ◽

Gene Pyramid ◽

High Level ◽

Resistance Spectrum

Abstract Background Rice blast caused by Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases in rice production. Development of resistant varieties through pyramiding of resistant (R) genes is considered as an effective strategy to cope with the disease. However, is it really essential to pyramid more R genes in a specific ecological regions? To answer this question, a set of rice improved lines were developed in this study. Afterwards, the blast disease resistance and agronomic traits of the recurrent parent (RP), donor parents (DPs) and improved lines were investigated. Results We developed seven improved lines, comprising three monogenic lines, three two-gene pyramids and one three-gene pyramid, by introgression of R gene(s) into a common genetic background using marker-assisted backcross breeding (MABB). Based on 302 SSR markers, the recurrent genome of the seven improved lines reached a range of 89.1 to 95.5%, with the average genome recovery of 92.9%. The pathogenicity assays inoculated with 32 different blast isolates under artificial conditions showed that the resistance spectrum of all the improved lines was significantly broadened. The assays further showed that the two-gene pyramids and the three-gene pyramid exhibited wider resistance spectrum than the monogenic lines. At natural nurseries, the three monogenic lines still showed high ratios of infected panicles, whereas the two-gene pyramids and the three-gene pyramid showed high level of panicle blast resistance. However, the two-gene pyramid R504 reached the similar resistance effect of the three-gene pyramid R507 considering resistance spectrum under artificial conditions and panicle blast resistance under field conditions. Generally, the improved lines showed comparable agronomic traits compared with the recurrent parent (RP), but the three-gene pyramid showed reduced grain yield per plant. Conclusions All the improved lines conferred wider resistance spectrum compared with the RP. Yet, the three monogenic lines did not work under field conditions of the two nurseries. Given the similar performances on the main agronomic traits as the RP, the two-gene pyramids have achieved the breeding goals of broad resistance spectrum and effective panicle blast resistance. Whereas, the three-gene pyramid harboring Pi2, Pi46 and Pita seems superfluous considering its reduced yield, although it also showed displayed high level of blast resistance. Thus, rational use of R genes rather than stacking more R genes is recommended to control the disease.

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