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

Chen, Xinglong; Jia, Yulin; Jia, Melissa H.; Pinson, Shannon R. M.; Wang, Xueyan; Wu, Boyang

doi:10.1094/phyto-02-18-0032-r

Cited by 10 publications

(6 citation statements)

References 47 publications

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“…Identifying both quantitative resistances and R genes which may be introgressed into a single cultivar is particularly important to help control disease in countries such as Brazil, where the MoT pathogen population is diverse and well established [ 24 ]. In rice, the stacking of three minor resistance QTL and the major R genes Pi-ta and Pi-b has been shown to have a positive additive effect on blast resistance to several isolates [ 42 ]. This demonstrates the advantages of combining both quantitative and R gene mediated resistance provided that the epistatic interactions between resistances are understood.…”

Section: Discussionmentioning

confidence: 99%

Dissecting the genetic basis of wheat blast resistance in the Brazilian wheat cultivar BR 18-Terena

et al. 2020

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Background Wheat blast, caused by Magnaporthe oryzae Triticum (MoT) pathotype, is a global threat to wheat ( Triticum aestivum L.) production. Few blast resistance ( R ) genes have been identified to date, therefore assessing potential sources of resistance in wheat is important. The Brazilian wheat cultivar BR 18-Terena is considered one of the best sources of resistance to blast and has been widely used in Brazilian breeding programmes, however the underlying genetics of this resistance are unknown. Results BR 18-Terena was used as the common parent in the development of two recombinant inbred line (RIL) F 6 populations with the Brazilian cultivars Anahuac 75 and BRS 179. Populations were phenotyped for resistance at the seedling and heading stage using the sequenced MoT isolate BR32, with transgressive segregation being observed. Genetic maps containing 1779 and 1318 markers, were produced for the Anahuac 75 × BR 18-Terena and BR 18-Terena × BRS 179 populations, respectively. Five quantitative trait loci (QTL) associated with seedling resistance, on chromosomes 2B, 4B (2 QTL), 5A and 6A, were identified, as were four QTL associated with heading stage resistance (1A, 2B, 4A and 5A). Seedling and heading stage QTL did not co-locate, despite a significant positive correlation between these traits, indicating that resistance at these developmental stages is likely to be controlled by different genes. BR 18-Terena provided the resistant allele for six QTL, at both developmental stages, with the largest phenotypic effect conferred by a QTL being 24.8% suggesting that BR 18-Terena possesses quantitative resistance. Haplotype analysis of 100 Brazilian wheat cultivars indicates that 11.0% of cultivars already possess a BR 18-Terena-like haplotype for more than one of the identified heading stage QTL. Conclusions This study suggests that BR 18-Terena possesses quantitative resistance to wheat blast, with nine QTL associated with resistance at either the seedling or heading stage being detected. Wheat blast resistance is also largely tissue-specific. Identification of durable quantitative resistances which can be combined with race-specific R gene-mediated resistance is critical to effectively control wheat blast. Collectively, this work facilitates marker-assisted selection to develop new varieties for cultivation in regions at risk from this emerging disease.

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Section: Discussionmentioning

confidence: 99%

Dissecting the genetic basis of wheat blast resistance in the Brazilian wheat cultivar BR 18-Terena

et al. 2020

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“…A 374bp-specific sequence of LMM8 was amplified from the wild type cDNA and was used for probe preparation with DIG. The sections were then pretreated, hybridized and immunologically tested with previous method ( Chen et al., 2018 ).…”

Section: Methodsmentioning

confidence: 99%

Lesion mimic mutant 8 balances disease resistance and growth in rice

et al. 2023

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Lesion-mimic mutants (LMM) spontaneously produce necrotic spots, a process not affected by environmental stress or pathogen infection. In this study, we identified a LMM, lesion mimic mutant 8 (lmm8) in rice (Oryza sativa). The lmm8 mutant produces brown and off-white lesions on its leaves during the second- and third-leaf stages. The lesion mimic phenotype of the lmm8 mutant was enhanced by light. At the mature stage, lmm8 mutant are shorter and exhibit inferior agronomic traits than the wild type. Contents of photosynthetic pigments and chloroplast fluorescence were significantly reduced in lmm8 leaves, along with increased production of reactive oxygen species and programmed cell death compared to the wild type. The mutated gene was identified as LMM8 (LOC_Os01g18320) by map-based cloning. A point mutation occurred in LMM8, causing a Leu to Arg mutation of the 146th amino acid of LMM8. It is an allele of SPRL1, encoding a protoporphyrinogen IX oxidase (PPOX) located in chloroplasts and involved in the biosynthesis of tetrapyrrole in chloroplasts. The lmm8 mutant showed enhanced resistance and broad-spectrum resistance. Together, our results demonstrate the importance of rice LMM8 protein in defense responses and plant growth in rice, and provides theoretical support for resistance breeding to improve rice yield.

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“…With improvements in technology, the cloning and exploitation of rice-blast R genes has seen tremendous progress in the twentyfirst century. To date, 119 blast R-genes and more than 400 quantitative trait loci (QTLs) have been mapped, and more than 30 blast-resistance genes have been mapped and cloned (Balliniet et al, 2008;Bryan et al, 2000;Chen et al, 2018a;Chen et al, 2006;Chen et al, 2018b;Fukuoka et al, 2009;Inoue et al, 2017;Hayashi et al, 2010;Ishihara et al, 2014;Li et al, 2017;Lin et al, 2007;Liu et al, 2002;Liu et al, 2007;Zhao et al, 2018).…”

Section: Current Status Of Cloning and Characterization Of Rice Blastmentioning

confidence: 99%

Identification of Novel Alleles of the Rice Blast-Resistance Gene Pi9 through Sequence-Based Allele Mining

Zhou

Lei

Wang

et al. 2020

Rice

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Background As rice (Oryza sativa) is the staple food of more than half the world’s population, rice production contributes greatly to global food security. Rice blast caused by the fungus Magnaporthe oryzae (M. oryzae) is a devastating disease that affects rice yields and grain quality, resulting in substantial economic losses annually. Because the fungus evolves rapidly, the resistance conferred by most the single blast-resistance genes is broken after a few years of intensive agricultural use. Therefore, effective resistance breeding in rice requires continual enrichment of the reservoir of resistance genes, alleles, or QTLs. Seed banks represent a rich source of genetic diversity; however, they have not been extensively used to identify novel genes and alleles. Results We carried out a large-scale screen for novel blast-resistance alleles in 1883 rice varieties from major rice-producing areas across China. Of these, 361 varieties showed at least moderate resistance to natural infection by rice blast at rice blast nurseries in Enshi and Yichang, Hubei Province. We used sequence-based allele mining to amplify and sequence the allelic variants of the major rice blast-resistance genes at the Pi2/Pi9 locus of chromosome 6 from the 361 blast-resistant varieties, and the full-length coding region of this gene could be amplified from 107 varieties. Thirteen novel Pi9 alleles (named Pi9-Type1 to Pi9-Type13) were identified in these 107 varieties based on comparison to the Pi9 referenced sequence. Based on the sequencing results, the Pi2/Pi9 locus of the 107 varieties was divided into 15 genotypes (including three different genotypes of Pi9-Type5). Fifteen varieties, each representing one genotype, were evaluated for resistance to 34 M. oryzae isolates. The alleles from seven varieties with the highest resistance and widest resistance spectra were selected for transformation into the susceptible variety J23B to construct near-isogenic lines (NILs). These NILs showed resistance in a field test in Enshi and Yichang, indicating that the seven novel rice blast-resistance tandem-repeat regions at the Pi2/Pi9 locus of chromosome 6 could potentially serve as a genetic resource for molecular breeding of resistance to rice blast. Conclusions The thirteen novel Pi9 alleles identified in this study expand the list of available of blast-resistance alleles. Seven tandem-repeat regions of the Pi2/Pi9 locus from different donors were characterized as broad-spectrum rice blast-resistance fragments; these donors enrich the genetic resources available for rice blast-resistance breeding programs.

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

Cited by 10 publications

References 47 publications

Dissecting the genetic basis of wheat blast resistance in the Brazilian wheat cultivar BR 18-Terena

Dissecting the genetic basis of wheat blast resistance in the Brazilian wheat cultivar BR 18-Terena

Lesion mimic mutant 8 balances disease resistance and growth in rice

Identification of Novel Alleles of the Rice Blast-Resistance Gene Pi9 through Sequence-Based Allele Mining

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