A Genome-Wide Meta-Analysis of Rice Blast Resistance Genes and Quantitative Trait Loci Provides New Insights into Partial and Complete Resistance

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.

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Functional Interactions Between Major Rice Blast Resistance Genes, Pi-ta and Pi-b, and Minor Blast Resistance Quantitative Trait Loci

Phytopathology ◽

10.1094/phyto-02-18-0032-r ◽

2018 ◽

Vol 108 (9) ◽

pp. 1095-1103 ◽

Cited By ~ 4

Author(s):

Xinglong Chen ◽

Yulin Jia ◽

Melissa H. Jia ◽

Shannon R. M. Pinson ◽

Xueyan Wang ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Quantitative Trait ◽

Rice Blast ◽

Blast Resistance ◽

R Genes ◽

Resistance Qtls ◽

Single Nucleotide ◽

Rice Blast Resistance ◽

Trait Loci ◽

Blast Resistance Genes

Major blast resistance (R) genes confer resistance in a gene-for-gene manner. However, little information is available on interactions between R genes. In this study, interactions between two rice blast R genes, Pi-ta and Pi-b, and other minor blast resistance quantitative trait loci (QTLs) were investigated in a recombinant inbred line (RIL) population comprising 243 RILs from a Cybonnet (CYBT) × Saber (SB) cross. CYBT has the R gene Pi-ta and SB has Pi-b. Ten differential isolates of four Magnaporthe oryzae races (IB-1, IB-17, IB-49, and IE-1K) were used to evaluate disease reactions of the 243 RILs under greenhouse conditions. Five resistance QTLs were mapped on chromosomes 2, 3, 8, 9, and 12 with a linkage map of 179 single nucleotide polymorphism markers. Among them, qBR12 (Q1), was mapped at the Pi-ta locus and accounted for 45.41% of phenotypic variation while qBR2 (Q2) was located at the Pi-b locus and accounted for 24.81% of disease reactions. The additive-by-additive epistatic interaction between Q1 (Pi-ta) and Q2 (Pi-b) was detected; they can enhance the disease resistance by an additive 0.93 using the 0 to 9 standard phenotyping method. These results suggest that Pi-ta interacts synergistically with Pi-b.

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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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Two novel gene-specific markers at pik locus facilitate the application of rice blast resistant alleles in breeding

10.21203/rs.2.18858/v1 ◽

2019 ◽

Author(s):

Dagang Tian ◽

Ziqiang Chen ◽

Yan Lin ◽

Zaijie Chen ◽

Jiami Luo ◽

...

Keyword(s):

Resistance Genes ◽

Rice Blast ◽

Blast Resistance ◽

Durable Resistance ◽

Resistance Breeding ◽

Blast Disease ◽

Chromosome 11 ◽

Rice Varieties ◽

Breeding Programs ◽

New Gene

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.

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Marker-assisted development and evaluation of monogenic lines of rice cv. Kaohsiung 145 carrying blast resistance genes

Plant Disease ◽

10.1094/pdis-01-21-0142-re ◽

2021 ◽

Author(s):

Yi-Chia Chen ◽

Chih-Chieh Hu ◽

Fang-Yu Chang ◽

Chieh-Yi Chen ◽

Wei-Lun Chen ◽

...

Keyword(s):

Resistance Genes ◽

Rice Blast ◽

Agronomic Traits ◽

Blast Resistance ◽

Natural Infection ◽

Durable Resistance ◽

Recurrent Parent ◽

Japonica Rice ◽

Sequencing Analysis ◽

Blast Resistance Genes

Rice blast is a serious threat to global rice production. Large-scale and long-term cultivation of rice varieties with a single blast resistance gene usually leads to breakdown of resistance. To effectively control rice blast in Taiwan, marker-assisted backcrossing was conducted to develop monogenic lines carrying different blast resistance genes in the genetic background of an elite japonica rice cultivar, ‘Kaohsiung 145’ (KH145). Eleven International Rice Research Institute (IRRI)-bred blast-resistant lines (IRBLs) showing broad-spectrum resistance to local Pyricularia oryzae isolates were used as resistance donors. Sequencing analysis revealed that the recurrent parent, KH145, does not carry known resistance alleles at the target Pi2/9, Pik, Pita, and Ptr loci. For each IRBL x KH145 cross, we screened 21–370 (average of 108) plants per generation from the BC1F1 to BC3F1/BC4F1 generation. A total of 1499 BC3F2/BC4F2 lines carrying homozygous resistance alleles were selected and self-crossed for 4–6 successive generations. The derived lines were also evaluated for background genotype using genotyping by sequencing, for blast resistance under artificial inoculation and natural infection conditions, and for agronomic performance in multiple field trials. In Chiayi and Taitung blast nurseries in 2018–2020, Pi2, Pi9, and Ptr conferred high resistance, Pi20 and Pik-h moderate resistance, and Pi1, Pi7, Pik-p, and Pik susceptibility to leaf blast; only Pi2, Pi9, and Ptr conferred effective resistance against panicle blast. The monogenic lines showed similar agronomic traits, yield, and grain quality as KH145, suggesting the potential of growing a mixture of lines to achieve durable resistance in the field.

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Effects of Pyramiding Quantitative Resistance Genes pi21, Pi34, and Pi35 on Rice Leaf Blast Disease

Plant Disease ◽

10.1094/pdis-02-14-0214-re ◽

2015 ◽

Vol 99 (7) ◽

pp. 904-909 ◽

Cited By ~ 26

Author(s):

Nobuko Yasuda ◽

Takayuki Mitsunaga ◽

Keiko Hayashi ◽

Shinzo Koizumi ◽

Yoshikatsu Fujita

Keyword(s):

Resistance Genes ◽

Blast Resistance ◽

Quantitative Resistance ◽

Durable Resistance ◽

Rice Cultivar ◽

Infection Process ◽

Blast Disease ◽

Leaf Blast ◽

Gene Combination ◽

Blast Resistance Genes

Development of resistant cultivars has been an effective method for controlling rice blast disease caused by Magnaporthe oryzae. Quantitative blast resistance genes may offer durable resistance because the selection pressure on M. oryzae to overcome resistance is low as a result of the genes’ moderate susceptibility. Because the effects of individual resistance genes are relatively small, pyramiding these genes in rice cultivars is a promising strategy. Here, we used near-isogenic and backcross lines of rice cultivar Koshihikari with single- or two-gene combinations of blast resistance genes (pi21, Pi34, and Pi35) to evaluate the suppression of leaf blast. The severity of the disease was assessed throughout the infection process. Resistance varied among the lines: Pi35 conferred the strongest resistance, while Pi34 showed the weakest effects. Two types of combined-gene interactions were observed, and they varied on the basis of gene combination and characteristic of the infection: (i) the combination of two resistance genes was more effective than either of the genes individually or (ii) the combination of two resistance genes was similar to the level of the most effective resistance gene in the pair. The most effective gene combination for the suppression of leaf blast was pi21 + Pi35.

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