Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Bangladesh

The pathogenicity of 331 blast isolates (Pyricularia oryzae Cavara) collected from different regions and ecosystems for rice cultivation in Bangladesh was evaluated by compatibility on 23 differential varieties (DV), each harboring a single blast resistance gene, and susceptible ‘Lijiangxintuanheigu’ (LTH). A wide variation in virulence was found among the isolates, and 267 races were classified using a new designation system. Virulence of blast isolates against DV carrying the resistance genes Pia, Pib, Pit, Pik-s, Piz-t, Pi12(t), Pi19(t), and Pi20(t), as well as avirulence against those carrying Pish, Pi9, Pita-2, and Pita, was distributed widely in Bangladesh. Cluster analysis of the compatibility data on the DV initially classified the isolates into groups I and II. The virulence spectra of the two groups differed mainly according to the reactions of the DV to Pii, Pi3, Pi5(t), Pik-m, Pi1, Pik-h, Pik, Pik-p, and Pi7(t). Group I isolates were distributed mainly in rainfed lowlands, whereas group II isolates were found mainly in irrigated lowlands; however, there were no critical differences in geographic distribution of the blast isolates. In total, 26 isolates, which could be used to identify the 23 resistance genes of the DV on the basis of their reaction patterns, were selected as a set of standard differential blast isolates. To our knowledge, this is the first clear demonstration of the diversity and differentiation of blast races in Bangladesh. This information will be used to develop a durable blast protection system in that country.

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Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Japan

Plant Disease ◽

10.1094/pdis-04-15-0442-re ◽

2016 ◽

Vol 100 (4) ◽

pp. 816-823 ◽

Cited By ~ 12

Author(s):

A. Kawasaki-Tanaka ◽

N. Hayashi ◽

S. Yanagihara ◽

Y. Fukuta

Keyword(s):

Cluster Analysis ◽

Rice Blast ◽

Oryza Sativa L ◽

Pyricularia Oryzae ◽

Central Japan ◽

Original Population ◽

Group I ◽

Differential Varieties ◽

Reaction Patterns ◽

Northern Japan

In total, 310 rice blast (Pyricularia oryzae Cavara) isolates from Japan showed wide variation in virulence. Virulence on rice (Oryza sativa L.) differential varieties (DV) harboring resistance genes Pish, Pia, Pii, Pi3, Pi5(t), Pik-s, and Pi19(t) ranged from 82.9 to 100.0%. In contrast, virulence on DV possessing Pib, Pit, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz, Piz-5, Piz-t, Pita-2, Pita, Pi12(t), and Pi20(t) ranged from 0 to 21.6%. Cluster analysis using the reaction patterns of the DV classified isolates into three groups: I, virulent to Pik, Pik-h, Pik-p, Pik-m, Pi1, and Pi7(t); IIa, avirulent to the preceding 6 genes and virulent to Pia, Pii, Pi3, and Pi5(t); and IIb, avirulent to all 10 genes. Group I was limited to northern Japan and group IIb to central Japan, while group IIa was distributed throughout Japan. We estimate that group IIa represents the original population and that groups I and IIb arose from it through minor changes in pathogenicity. We classified these isolates into 123 races by a new designation system and conclude that the rice blast races in Japan are less diverse than previously thought.

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Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Vietnam

Plant Disease ◽

10.1094/pdis-05-19-1008-re ◽

2020 ◽

Vol 104 (2) ◽

pp. 381-387 ◽

Cited By ~ 1

Author(s):

Nguyen T. M. Nguyet ◽

Hoang H. Long ◽

Nguyen B. Ngoc ◽

Nguyen T Nhai ◽

Nguyen T. T. Thuy ◽

...

Keyword(s):

Resistance Genes ◽

Rice Blast ◽

Pyricularia Oryzae ◽

Red River ◽

Red River Delta ◽

North Central ◽

South Central ◽

Central Vietnam ◽

Differential Varieties ◽

Reaction Patterns

A total of 239 isolates of blast (Pyricularia oryzae Cavara) collected from northern and central Vietnam showed a wide variation in pathogenicity based on the reaction patterns to 25 differential varieties (DVs) harboring 23 resistance genes and susceptible cultivar Lijiangxintuanheigu (LTH). The frequencies of isolates virulent toward DVs for Pish, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz-5, Pita-2, and Pita were low, but they were high for DVs for Pib, Pit, Pia, Pii, Pi3, Pi5(t), Pik-s, Piz, Piz-t, Pi12(t), Pi19(t), and Pi20(t). Isolates were classified into three cluster groups Ia, Ib, and II based on reaction patterns to DVs and LTH. The frequencies of isolates virulent toward 11 DVs for Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz, Piz-5, Pita-2, and Pita in cluster II and DV for Piz-t were higher and lower than those of Ia and Ib, respectively. The frequencies to DVs for Pii, Pi3, Pi5(t), and Piz-t were different between clusters Ia and Ib. Clusters Ia and Ib were distributed with similar frequencies in the northeast, north central, and south central coast regions, but the frequencies among three cluster groups in the Red River Delta and northwest regions were different. This means that the blast races in these two regions were different from the others. Overall, the blast isolates were categorized into 153 races. Among them, 26 were selected as a set of standard differential blast isolates for characterizing 23 resistance genes and developing a differential system in Vietnam.

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Pathogenicities of Rice Blast (Pyricularia oryzae Cavara) Isolates From Kenya

Plant Disease ◽

10.1094/pdis-04-19-0870-re ◽

2019 ◽

Vol 103 (12) ◽

pp. 3181-3188 ◽

Cited By ~ 1

Author(s):

Yoshimichi Fukuta ◽

Mary Jeanie Telebanco-Yanoria ◽

Nagao Hayashi ◽

Seiji Yanagihara ◽

Catherine Wanjiku Machungo ◽

...

Keyword(s):

Resistance Genes ◽

Rice Blast ◽

Pyricularia Oryzae ◽

The Other ◽

Tana River ◽

Geographical Regions ◽

Differential Varieties ◽

Reaction Patterns

A total of 99 isolates of rice blast (Pyricularia oryzae Cavara) were collected from 2010 to 2015 from four regions in Kenya: Kirinyaga County and Embu County, Kisumu County, Tana River County, and Mombasa County. The pathogenicities of these isolates were clarified based on the reaction patterns of Lijiangxintuanheigu and differential varieties (DVs) targeting 23 resistance genes. The frequency of virulent isolates was high for DVs for Pib, Pia, Pii, Pi3, Pi5(t), Pik-s, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi19(t), and Pi20(t); low for DVs for Pish, Pi9(t), Piz-5, and Piz-t; and intermediate for the remaining DVs for Pit, Piz, Pita-2, Pita, and Pi12(t). These blast isolates were classified into three cluster groups: Ia, Ib, and II. The frequencies of virulent isolates to DVs for Pit, Pii, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Piz, and Pi12(t) differed markedly between clusters I and II, and those of DVs for Pib, Pit, Pia, Pi3, Pita-2, Pita, and Pi20(t) differed between Ia and Ib. The frequencies of cluster groups in the four geographical regions were different. A total of 62 races were found, with 19 blast isolates categorized into one race (U63-i7-k177-z00-ta003), whereas the other races included only some isolates in each.

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Pathogenicity of Isolates of the Rice Blast Pathogen (Pyricularia oryzae) from Indonesia

Plant Disease ◽

10.1094/pdis-05-20-0949-re ◽

2020 ◽

Author(s):

Santoso Kadeawi ◽

Suwarno Non ◽

Anggiani Nasution ◽

Aris Hairmansis ◽

Mitsuhiro Obara ◽

...

Keyword(s):

Differential System ◽

Resistance Genes ◽

Rice Blast ◽

Pyricularia Oryzae ◽

The Other ◽

Blast Disease ◽

Rice Cultivars ◽

Rice Ecosystems ◽

Susceptible Control ◽

Differential Varieties

A total of 201 isolates of Pyricularia oryzae (the causal agent of rice blast) were collected from three rice ecosystems (upland, lowland, and swampy) in five regions of Indonesia (West Java, Lampung, South Sumatra, Kalimantan, and Bali). Their pathogenicities were characterized based on the patterns of reaction of 25 differential varieties (DVs) and the susceptible control Lijiangxintuanheigu (LTH), which was susceptible to all blast isolates. A high proportion of isolates (>80.0%) were virulent to DVs for resistance genes Pib, Pit, Pia, Pik-s, and Pi12(t), and a low proportion of isolates (<12.9%) were virulent to DVs for Pik-m, Pi1, Pik-h, Pik, Pik-p, and Pi7(t). Virulence to the other DVs for Pish, Pii, Pi3, Pi5(t), Pi9(t), Piz, Piz-5, Piz-t, Pita-2 (two lines), Pita (two lines), Pi19(t), and Pi20(t) showed intermediate frequencies from 20.0% to 80.0%. These isolates were classified into three cluster groups Ia, Ib, and II, and the frequencies of cluster groups varied among the three ecosystems and the five regions. The frequencies of cluster groups varied among the different ecosystems and regions, and races varied according to the ecosystems. A total of 27 standard differential blast isolates (SDBLs) were selected from the 201 isolates collected. The set of 25 DVs and these 27 SDBIs will be used as a new differential system for analysis of the pathogenicity of blast isolates and analysis of resistance genes in rice cultivars, which will contribute to building up a durable protection system against blast disease in Indonesia.

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Virulence Pattern of Pyricularia oryzae Pathotypes Towards Blast Monogenic Lines

Tropical Life Sciences Research ◽

10.21315/tlsr2021.32.3.8 ◽

2021 ◽

Vol 32 (3) ◽

pp. 147-160

Author(s):

Siti Norsuha Misman ◽

Mohd Shahril Firdaus Ab Razak ◽

Nur Syahirah Ahmad Sobri ◽

Latiffah Zakaria

Keyword(s):

Resistance Genes ◽

Rice Blast ◽

Blast Resistance ◽

Rice Variety ◽

Durable Resistance ◽

Peninsular Malaysia ◽

Pyricularia Oryzae ◽

Blast Disease ◽

Breeding Lines ◽

Virulence Pattern

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.

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Effectiveness of the Wheat Blast Resistance Gene Rmg8 in Bangladesh Suggested by Distribution of an AVR-Rmg8 Allele in the Pyricularia oryzae Population

Phytopathology ◽

10.1094/phyto-03-20-0073-r ◽

2020 ◽

Vol 110 (11) ◽

pp. 1802-1807

Author(s):

Jemal Tola Horo ◽

Soichiro Asuke ◽

Trinh Thi Phuong Vy ◽

Yukio Tosa

Keyword(s):

Resistance Gene ◽

Resistance Genes ◽

Blast Resistance ◽

Pyricularia Oryzae ◽

Avirulence Gene ◽

Sequence Analyses ◽

Blast Resistance Gene ◽

Wheat Blast ◽

Higher Temperature ◽

Heading Stage

Wheat blast caused by the Triticum pathotype of Pyricularia oryzae was first reported in 1985 in Brazil and recently spread to Bangladesh. We tested whether Rmg8 and RmgGR119, recently identified resistance genes, were effective against Bangladeshi isolates of the pathogen. Common wheat accessions carrying Rmg8 alone (IL191) or both Rmg8 and RmgGR119 (GR119) were inoculated with Brazilian isolates (Br48, Br5, and Br116.5) and Bangladeshi isolates (T-108 and T-109). Br48, T-108, and T-109 carried the eI type of AVR-Rmg8 (the avirulence gene corresponding to Rmg8) while Br5 and Br116.5 carried its variants, eII and eII’ types, respectively. Detached primary leaves of IL191 and GR119 were resistant to all isolates at 25°C. At a higher temperature (28°C), their resistance was still effective against the eI carriers but was reduced to a low level against the eII/eII’ carriers. A survey of databases and sequence analyses revealed that all Bangladeshi isolates carried the eI type which induced a higher level of resistance than the eII/eII’ types. The resistance of IL191 (Rmg8/−) to the eI carriers was maintained even at the heading stage and at the higher temperature. In addition, GR119 (Rmg8/RmgGR119) displayed higher levels of resistance than IL191 at this stage. These results suggest that Rmg8 combined with RmgGR119 will be useful in breeding for resistance against wheat blast in Bangladesh.

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