Investigating the biology of rice blast disease and prospects for durable resistance

2021 ◽  
pp. 643-680
Author(s):  
Vincent M. Were ◽  
◽  
Nicholas J. Talbot ◽  

There are important biological process involved in rice blast disease that are now well-studied during the early events in plant infection which include: the cell biology of appressorium formation, the biology of invasive growth and effector secretion, the two distinct mechanisms of effector secretion, the nature of the plant-pathogen interface, PAMP-triggered immunity modulation by secreted effectors and effector-triggered immunity and blast resistance. The devastating losses caused by the blast fungus have been documented in most grasses, but this chapter discusses the use of major resistance genes to rice blast and wheat blast disease as an emerging threat to global food security. This chapter also highlights an emerging approach to breed for durable resistance to plant pathogens using gene editing technologies with an example: CRISPR-Cas9 mutagenesis of dominant S-genes for disease control.

Plant Disease ◽  
2021 ◽  
Author(s):  
Samuel K Mutiga ◽  
Felix Rotich ◽  
Vincent M Were ◽  
John Kimani ◽  
David Thuranira Mwongera ◽  
...  

Rice is a key food security crop in Africa. The importance of rice has led to increasing country-specific, regional and multinational efforts to develop germplasm and policy initiatives to boost production for a more food secure continent. Currently, this critically important cereal crop is predominantly cultivated by small-scale farmers under sub-optimal conditions in most parts of sub-Saharan Africa (SSA). Rice blast disease, caused by the fungus Magnaporthe oryzae, represents one of the major biotic constraints to rice production under small-scale farming systems of Africa, and developing durable disease resistance is therefore of critical importance. In this review, we provide an overview of the major advances by a multinational collaborative research effort to enhance sustainable rice production across SSA and how it is affected by advances in regional policy. As part of the multinational effort, we highlight the importance of joint international partnerships in tackling multiple crop production constraints through integrated research and outreach programs. More specifically, we highlight recent progress in establishing international networks for rice blast disease surveillance, farmer engagement, monitoring pathogen virulence spectra, and the establishment of regionally-based blast resistance breeding programs. To develop blast resistant, high yielding rice varieties for Africa, we have established a breeding pipeline that utilizes real-time data of pathogen diversity and virulence spectra, to identify major and minor blast resistance genes for introgression into locally adapted rice cultivars. In addition, the project has developed a package to support sustainable rice production through regular stakeholder engagement, training of agricultural extension officers, and establishment of plant clinics.


2008 ◽  
Vol 21 (7) ◽  
pp. 859-868 ◽  
Author(s):  
Elsa Ballini ◽  
Jean-Benoît Morel ◽  
Gaétan Droc ◽  
Adam Price ◽  
Brigitte Courtois ◽  
...  

The completion of the genome sequences of both rice and Magnaporthe oryzae has strengthened the position of rice blast disease as a model to study plant–pathogen interactions in monocotyledons. Genetic studies of blast resistance in rice were established in Japan as early as 1917. Despite such long-term study, examples of cultivars with durable resistance are rare, partly due to our limited knowledge of resistance mechanisms. A rising number of blast resistance genes and quantitative trait loci (QTL) have been genetically described, and some have been characterized during the last 20 years. Using the rice genome sequence, can we now go a step further toward a better understanding of the genetics of blast resistance by combining all these results? Is such knowledge appropriate and sufficient to improve breeding for durable resistance? A review of bibliographic references identified 85 blast resistance genes and approximately 350 QTL, which we mapped on the rice genome. These data provide a useful update on blast resistance genes as well as new insights to help formulate hypotheses about the molecular function of blast QTL, with special emphasis on QTL for partial resistance. All these data are available from the OrygenesDB database.


Author(s):  
V. M. L. Jackson ◽  
P. Rubaihayo ◽  
P. Wasswa ◽  
A. T. Hashim

Rice blast disease is the most destructive disease to rice plants and can cause a lost in a yield ranging from 50 to 100%. To develop resistant genotypes, it is necessary to determine the source of resistance, the nature of resistance and the mode of gene action that gives resistance to the disease. It is known that Silicon enhances durable resistance to rice blast disease. The rice silicon uptake inheritance can be studied through crossing the high silicon uptake with low silicon uptake genotypes. Seven genotypes were crossed in a full-dialel design, two genotypes having very high silicon uptake ability, two having moderate silicon ability, two having low silicon uptake ability and the last one was having very low silicon ability. The F1 plants were selfed and F2 plants were tested for silicon uptake ability. Then genetic traits of the segregating F2 populations and their parents were analyzed in order to determine the heritability. A high narrow sense coefficient of genetic determination suggested that there was a considerable heritability of resistance for rice blast. The analysis of gene action revealed that additive gene effects contributed more than the non-additive effects for the inheritance of silicon uptake ability as indicated by high Baker’s ratio (above 0.8 and 0.3) for both silicon uptake and water lose respectively. Genotypes, GIZA182 and E20 were found to have the most desirable GCA among the genotypes used in the study.


2021 ◽  
Author(s):  
Lili Wang ◽  
Zuobin Ma ◽  
Houxiang Kang ◽  
Shuang Gu ◽  
Zhanna Mukhina ◽  
...  

Abstract Rice blast seriously threatens rice production worldwide. Utilizing the rice blast resistance gene to breed the rice blast resistant varieties is one of the best ways to control rice blast disease. Using a map-based cloning strategy, here, we cloned a novel rice blast resistance gene, Pi65 from the resistant variety GangYu129 (abbreviated GY129, O. sativa japonica ). Overexpression of Pi65 in the susceptible variety LiaoXing1 (abbreviated LX1, O. sativa japonica ) enhanced rice blast resistance, while knockout of Pi65 in GY129 resulted in susceptible to rice blast disease. Pi65 encodes two transmembrane domains, with 15 LRR domains and one serine/threonine protein kinase catalytic domain, conferring resistance to isolates of M. oryzae collected from northeast China. There are sixteen amino acids differences between the Pi65 resistance and susceptible alleles. Compared with the Pi65 resistant allele, the susceptible allele deleted one LRR domain. Pi65 was constitutively expressed in whole plants, and it could be induce expressed in the early stage of M. oryzae infection . Transcriptome analysis revealed that numerous genes associated with disease resistance were specifically upregulated in GY129 24-hour post inoculation (HPI), on the contrary, the photosynthesis-and carbohydrate metabolism-related genes were particularly downregulated 24 HPI, demonstrating that the disease resistance associated genes has been activated in GY129 (carrying Pi65 ) after rice blast fungal infection, and the cellular basal and energy metabolism was inhibited simultaneously. Our study provides genetic resources for improving rice blast resistance as well as enriches the study of rice blast resistance mechanisms.


2021 ◽  
Vol 32 (3) ◽  
pp. 147-160
Author(s):  
Siti Norsuha Misman ◽  
Mohd Shahril Firdaus Ab Razak ◽  
Nur Syahirah Ahmad Sobri ◽  
Latiffah Zakaria

Rice blast caused by Pyricularia oryzae (P. oryzae) is one of the most serious diseases infecting rice worldwide. In the present study, virulence pattern of six P. oryzae pathotypes (P0.0, P0.2, P1.0, P3.0, P7.0 and P9.0) identified from the blast pathogen collected in Peninsular Malaysia, were evaluated using a set of 22 IRRI-bred blast resistance lines (IRBL) as well as to determine the resistance genes involved. The information on the virulence of the blast pathotypes and the resistance genes involved is important for breeding of new rice variety for durable resistance against blast disease. The IRBL was established from 22 monogenic lines, harbouring 22 resistance genes [Pia, Pib, Pii, Pit, Pi3, Pi5(t), Pish, Pi1, Pik, Pik-s, Pik-m, Pik-h, Pik-p, Pi7(t), Pi9, Piz, Piz-5, Piz-t, Pi19, Pi20(t), Pita-2, and Pita=Pi4(t)]. Based on the disease severity patterns, the tested pathotypes were avirulence towards seven IRBLs [IRBLi-F5, IRBLk-Ka, IRBLkh-K3, IRBLz-Fu, IRBLsh-S, IRBLPi7 (t) and IRBL9-W] of which these IRBLs harbouring Pii, Pik, Pik-h, Piz, Pish, Pi7(t) and Pi9 resistance genes, respectively. Therefore, the results suggested that the seven IRBLs carrying seven resistance genes [Pii, Pik, Pik-h, Piz, Pish, Pi7(t) and Pi9] would be suitable candidates of resistance genes to be incorporated in new breeding lines to combat the current blast pathotypes in the field.


2019 ◽  
Author(s):  
Dagang Tian ◽  
Ziqiang Chen ◽  
Yan Lin ◽  
Zaijie Chen ◽  
Jiami Luo ◽  
...  

Abstract Background: Rice blast disease, caused by Magnaporthe oryzae, is a major constraint for rice production in the world. Introgression of blast-durable resistance genes into high-yielding rice cultivars has been considered an agricultural priority in an effort to control the disease. The blast resistance Pik locus, located on chromosome 11, contains at least six important resistance genes, but these genes have not been widely employed in resistance breeding since existing markers hardly satisfy current breeding needs owing to their limited scope of application.Results: In the present study, two PCR-based markers, Pikp-Del and Pi1-In, were developed to target the specific InDel (insertion/deletion) of the Pik-p and Pi-1 genes, respectively. The two markers precisely distinguished Pik-p, Pi-1, and the K-type alleles at the Pik locus, which is a necessary element for functional genes from rice varieties. Conclusions:Two gene-specific markers of Pi-kp and Pi1 identified that only several old varieties contain the two genes, nearly half these varieties yet carry the K-type alleles. Therefore, these identified varieties can be new gene sources for developing blast resistant rice. The two newly developed markers should be highly useful for using Pi-kp, Pi1 and other resistance genes at the Pik locus in marker-assisted selection (MAS) breeding programs.


2015 ◽  
Vol 28 (12) ◽  
pp. 1383-1392 ◽  
Author(s):  
Xueyan Wang ◽  
Melissa H. Jia ◽  
Pooja Ghai ◽  
Fleet N. Lee ◽  
Yulin Jia

Robust disease resistance may require an expenditure of energy that may limit crop yield potential. In the present study, a subset of a United States Department of Agriculture rice core collection consisting of 151 accessions was selected using a major blast resistance (R) gene, Pi-ta, marker and was genotyped with 156 simple sequence repeat (SSR) markers. Disease reactions to Magnaporthe oryzae, the causal agent of rice blast disease, were evaluated under greenhouse and field conditions, and heading date, plant height, paddy and brown seed weight in two field environments were analyzed, using an association mapping approach. A total of 21 SSR markers distributed among rice chromosomes 2 to 12 were associated with blast resistance, and 16 SSR markers were associated with seed weight, heading date, and plant height. Most noticeably, shorter plants were significantly correlated with resistance to blast, rice genomes with Pi-ta were associated with lighter seed weights, and the susceptible alleles of RM171 and RM6544 were associated with heavier seed weight. These findings unraveled a complex relationship between disease resistance and yield-related components.


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