An Allelic Variant of the Broad-Spectrum Blast Resistance Gene Ptr in Weedy Rice is Associated with Resistance to the Most Virulent Blast Race IB-33

Plant Disease ◽  
2021 ◽  
Author(s):  
Haijun Zhao ◽  
Yan Liu ◽  
Melissa H Jia ◽  
Yulin Jia
Keyword(s):  
Resistance Gene ◽  
Broad Spectrum ◽  
Mapping Population ◽  
Blast Resistance ◽  
Snp Markers ◽  
Blast Disease ◽  
Weedy Rice ◽  
Specific Marker ◽  
R Genes ◽  
Cultivated Rice

Rice resistance (R) genes have been effectively deployed to prevent blast disease caused by the pathogen Magnaporthe oryzae, one of the most serious threats for stable rice production worldwide. Weedy rice competing with cultivated rice may carry novel or lost R genes. The QTL qBR12.3b was previously mapped between two single nucleotide polymorphism (SNP) markers 10,633,942 bp and 10,820,033 bp in a black hull awned (BHA) weed strain using a weed-crop mapping population under greenhouse conditions. In the present study, we found a portion of the known resistance gene Ptr encoding a protein with 4 armadillo repeats and confers a broad spectrum of blast resistance. We then analyzed the sequences of the Ptr gene from weedy rice, PtrBHA, identified a unique amino acid glutamine (Gln) at protein position 874. Minor changes of protein conformation of the PtrBHA gene were predicted through structural analysis of PtrBHA suggesting the product of PtrBHA is involved in disease resistance. A gene-specific codominant marker HJ17-13 from PtrBHA was then developed to distinguish alleles in weed and crop. The existence of the PtrBHA gene in 207 individuals of the same mapping population where qBR12.3b was mapped using this gene-specific marker. Disease reactions of 207 individuals and their parents to IB-33 were evaluated. The resistant individuals had the PtrBHA whereas the susceptible individuals did not suggest HJ17-13 is reliable to predict qBR12.3b. Taken together, this newly developed marker and weedy rice genotypes carrying qBR12.3b are useful for blast improvement using marker assisted selection.

scholarly journals QTL Analysis for Resistance to Blast Disease in U.S. Weedy Rice

2015 ◽  
Vol 28 (7) ◽  
pp. 834-844 ◽  
Author(s):  
Yan Liu ◽  
Xinshuai Qi ◽  
Dave R. Gealy ◽  
Kenneth M. Olsen ◽  
Ana L. Caicedo ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
Blast Resistance ◽  
Genotyping By Sequencing ◽  
Blast Disease ◽  
Weedy Rice ◽  
R Genes ◽  
Cultivated Rice ◽  
Local Conditions ◽  
Resistance Qtl ◽  
Resistance Spectrum

Understanding the genetic architecture of adaptation is of great importance in evolutionary biology. U.S. weedy rice is well adapted to the local conditions in U.S. rice fields. Rice blast disease is one of the most destructive diseases of cultivated rice worldwide. However, information about resistance to blast in weedy rice is limited. Here, we evaluated the disease reactions of 60 U.S. weedy rice accessions with 14 blast races, and investigated the quantitative trait loci (QTL) associated with blast resistance in two major ecotypes of U.S. weedy rice. Our results revealed that U.S. weedy rice exhibited a broad resistance spectrum. Using genotyping by sequencing, we identified 28 resistance QTL in two U.S. weedy rice ecotypes. The resistance QTL with relatively large and small effects suggest that U.S. weedy rice groups have adapted to blast disease using two methods, both major resistance (R) genes and QTL. Three genomic loci shared by some of the resistance QTL indicated that these loci may contribute to no-race-specific resistance in weedy rice. Comparing with known blast disease R genes, we found that the R genes at these resistance QTL are novel, suggesting that U.S. weedy rice is a potential source of novel blast R genes for resistant breeding.

scholarly journals Genotyping for Blast (Pyricularia oryzae) Resistance Genes in F2 Population of Supa Aromatic Rice (Oryza sativa L.)

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
L. Kanyange ◽  
J. Kamau ◽  
O. Ombori ◽  
A. Ndayiragije ◽  
M. Muthini
Keyword(s):  
Host Plants ◽  
Oryza Sativa L ◽  
Blast Resistance ◽  
Rice Variety ◽  
Snp Markers ◽  
Pyricularia Oryzae ◽  
Blast Disease ◽  
Aromatic Rice ◽  
R Genes ◽  
F2 Population

The ascomycete fungus, Pyricularia oryzae or Magnaporthe oryzae, is known to cause blast disease in more than 80 host plants of the Gramineae family—cereals including rice and grasses. The improvement of the Supa234 rice line (IR97012-27-3-1-1-B, containing badh2 gene for aroma) developed at IRRI-ESA Burundi consisted of introgression of R genes (Pita and Pi9) for blast resistance. The F2 population obtained via the cross had been screened for blast resistance using inoculation with Pyricularia oryzae spore’s suspension. The objectives of this study were to assess the presence of Pita and Pi9 genes for blast resistance and to assess the presence of the badh2 gene for aroma in the screened F2 plants using molecular markers. Genotyping was carried out in 103 F2 plants which grew to maturity using the KASP genotyping method with SNP markers (snpOS0007, snpOS0006, and snpOS0022) targeting the Pita and Pi9 genes for blast resistance and the badh2 gene for aromatic fragrance. The genotyping results showed that 38 F2 plants had the Pita gene present in both alleles, 31 F2 plants with the Pita gene in one allele, and only one plant (3B1) was found with the Pi9 gene in one allele. The badh2 gene for aroma was detected in 27 F2 plants on both alleles and in 57 F2 plants on one allele. There were thirteen plants which had both the Pita gene and the badh2 gene for aroma, and only one plant (3B1) had a combination of the three genes (Pita, Pi9, and badh2). Seven plants resistant to blast disease (2H2, 2H4, 1G2, 1C12, 1E13, 1B12, and 1C5) with the Pita and badh2 genes were found, and only one resistant plant (3B1) had a combination of the three genes Pi9, Pita, and badh2 which is recommended to be bulked for the development of the Supa aromatic rice variety resistant to blast disease. The plants generated by the best line 3B1 should further be evaluated for grain quality (Supa type) after F5 generation in the field.

scholarly journals Level of Endogenous Jasmonate is Critical for Durable Broad-Spectrum Disease Resistance Against Rice Blast in a Japonica Rice Variety, Ziyu44

2021 ◽  
Author(s):  
Xingyu An ◽  
Hui Zhang ◽  
Jinlu Li ◽  
Rui Yang ◽  
Qianchun Zeng ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Signaling Pathway ◽  
Broad Spectrum ◽  
Rice Blast ◽  
Blast Resistance ◽  
Rice Variety ◽  
Blast Disease ◽  
Japonica Rice ◽  
Mycelium Growth ◽  
Broad Spectrum Resistance

Abstract Background: The molecular mechanism of durable and broad-spectrum resistance to rice blast disease in japonica rice variety is still very little known. Ziyu44, a local japonica rice variety in Yunnan Province of China, has shown durable broad-spectrum blast resistance for more than 30 years, and provides an opportunity for us to explore the molecular basis of broad-spectrum resistance to rice blast in japonica rice variety.Methods and Results: We conducted a comparative study of mycelium growth, aposporium formation, the accumulation of salicylate(SA), jasmonate(JA) and H2O2, the expression of SA- and JA-associated genes between Ziyu44 and susceptible variety Jiangnanxiangnuo (JNXN) upon M. oryzae infection. We found that appressorium formation and invasive hyphae extention were greatly inhibited in Ziyu 44 leaves compared with that in JNXN leaves. Both Ziyu 44 and JNXN plants maintained high levels of baseline SA and did not show increased accumulation of SA after inoculation with M. oryzae, while the levels of baseline JA in Ziyu 44 and JNXN plants were relatively low, and the accumulation of JA exhibited markedly increased in Ziyu 44 plants upon M. oryzae infection. The expression levels of key genes involving JA and SA signaling pathway OsCOI1b, OsNPR1, OsMPK6 as well as pathogenesis-related (PR) genes OsPR1a, OsPR1b and OsPBZ1, were markedly up-regulated in Ziyu44. Conclusions: The level of endogenous JA is critical for synchronous activation of SA and JA signaling pathway, up-regulating PR gene expression and enhancing disease resistance against rice blast in Ziyu44.

Identification of three major R genes responsible for broad-spectrum blast resistance in an indica rice accession

2015 ◽  
Vol 35 (1) ◽  
Author(s):  
Wuming Xiao ◽  
Qiyun Yang ◽  
Dayuan Sun ◽  
Hui Wang ◽  
Tao Guo ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Blast Resistance ◽  
Indica Rice ◽  
R Genes ◽  
Rice Accession

scholarly journals Exploring the Distribution of Blast Resistance Alleles at the Pi2/9 Locus in Major Rice-Producing Areas of China by a Novel Indel Marker

Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1932-1938
Author(s):  
Dagang Tian ◽  
Yan Lin ◽  
Ziqiang Chen ◽  
Zaijie Chen ◽  
Fang Yang ◽  
...  
Keyword(s):  
Blast Resistance ◽  
Resistance Breeding ◽  
Field Trials ◽  
Indel Marker ◽  
Blast Disease ◽  
Cereal Crops ◽  
R Genes ◽  
Rice Varieties ◽  
Environment Friendly ◽  
The World

Rice blast disease caused by the fungus Magnaporthe oryzae damages cereal crops and poses a high risk to rice production around the world. Currently, planting cultivars with resistance (R) genes is still the most environment-friendly approach to control this disease. Effective identification of R genes existing in diverse rice cultivars is important for understanding the distribution of R genes and predicting their contribution to resistance against blast isolates in regional breeding. Here, we developed a new insertion/deletion (InDel) marker, Pigm/2/9InDel, that can differentiate the cloned R genes (Pigm, Pi9, and Pi2/Piz-t) at the Pi2/9 locus. Pigm/2/9InDel combined with the marker Pi2-LRR for Pi2 was applied to determine the distribution of these four R genes among 905 rice varieties, most of which were collected from the major rice-producing regions in China. In brief, nine Pigm-containing varieties from Fujian and Guangdong provinces were identified. All of the 62 Pi2-containing varieties were collected from Guangdong, and 60 varieties containing Piz-t were from seven provinces. However, Pi9 was not found in any of the Chinese varieties. The newly identified varieties carrying the Pi2/9 alleles were further subjected to inoculation tests with regional blast isolates and field trials. Our results indicate that Pigm and Pi2 alleles have been introgressed for blast resistance breeding mainly in the Fujian and Guangdong region, and Pi9 is a valuable blast resistance resource to be introduced into China.

scholarly journals Fine Mapping of a New Race-Specific Blast Resistance Gene, Pi-hk2, in Japonica Heikezijing from Taihu Region of China

2017 ◽  
Vol 107 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Wanwan He ◽  
Nengyan Fang ◽  
Ruisen Wang ◽  
Yunyu Wu ◽  
Guoying Zeng ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Fine Mapping ◽  
Broad Spectrum ◽  
Blast Resistance ◽  
Recombinant Inbred Lines ◽  
Japonica Rice ◽  
Phenotypic Variance ◽  
Chromosome 11 ◽  
Essential Information ◽  
Broad Spectrum Resistance

Heikezijing, a japonica rice landrace from the Taihu region of China, exhibited broad-spectrum resistance to more than 300 isolates of the blast pathogen (Magnaporthe oryzae). In our previous research, we fine mapped a broad-spectrum resistance gene, Pi-hk1, in chromosome 11. In this research, 2010-9(G1), one of the predominant races of blast in the Taihu Lake region of China, was inoculated into 162 recombinant inbred lines (RIL) and two parents, Heikezijing and Suyunuo, for mapping the resistance-blast quantitative trait loci (QTL). Three QTL (Lsqtl4-1, Lsqtl9-1, and Lsqtl11-1) associated with lesion scores were detected on chromosomes 4, 9, and 11 and two QTL (Lnqtl1-1 and Lnqtl9-1) associated with average lesion numbers were detected on chromosomes 1 and 9. The QTL Lsqtl9-1 conferring race-specific resistance to 2010-9(G1) at seedling stages showed logarithm of the odds scores of 9.10 and phenotypic variance of 46.19% and might be a major QTL, named Pi-hk2. The line RIL84 with Pi-hk2 derived from a cross between Heikezijing and Suyunuo was selected as Pi-hk2 gene donor for developing fine mapping populations. According to the resistance evaluation of recombinants of three generations (BC1F2, BC1F3, and BC1F4), Pi-hk2 was finally mapped to a 143-kb region between ILP-19 and RM24048, and 18 candidate genes were predicted, including genes that encode pleiotropic drug resistance protein 4 (n = 2), WRKY74 (n = 1), cytochrome b5-like heme/steroid-binding domain containing protein (n = 1), protein kinase (n = 1), and ankyrin repeat family protein (n = 1). These results provide essential information for cloning of Pi-hk2 and its potential utility in breeding resistant rice cultivars by marker-assisted selection.

scholarly journals A Rapid Survey of Avirulence Genes in Field Isolates of Magnaporthe oryzae

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 717-723
Author(s):  
Zhen Zhang ◽  
Yulin Jia ◽  
Yanli Wang ◽  
Guochang Sun
Keyword(s):  
United States ◽  
Magnaporthe Oryzae ◽  
Blast Resistance ◽  
Blast Disease ◽  
Southern United States ◽  
R Genes ◽  
Field Isolates ◽  
Pcr Products ◽  
Avr Gene ◽  
Avr Genes

Magnaporthe oryzae is the causal agent for the devastating disease rice blast. The avirulence (AVR) genes in M. oryzae are required to initiate robust disease resistance mediated by the corresponding resistance (R) genes in rice. Therefore, monitoring pathogen AVR genes is important to predict the stability of R gene-mediated blast resistance. In the present study, we analyzed the DNA sequence dynamics of five AVR genes, namely, AVR-Pita1, AVR-Pik, AVR-Pizt, AVR-Pia, and AVR-Pii, in field isolates of M. oryzae in order to understand the effectiveness of the R genes, Pi-ta, Pi-k, Pi-zt, Pia, and Pii in the Southern U.S. rice growing region. Genomic DNA of 258 blast isolates collected from commercial fields of the Southern UNITED STATES during 1975–2009 were subjected to PCR amplification with AVR gene-specific PCR markers. PCR products were obtained from 232 isolates. The absence of PCR products in the remaining 26 isolates suggests that these isolates do not contain the tested AVR genes. Amplified PCR products were subsequently gel purified and sequenced. Based on the presence or absence of the five AVR genes, 232 field isolates were classified into 10 haplotype groups. The results revealed that 174 isolates of M. oryzae carried AVR-Pita1, 225 isolates carried AVR-Pizt, 44 isolates carried AVR-Pik, 3 isolates carried AVR-Pia, and one isolate carried AVR-Pii. AVR-Pita1 was highly variable, and 40 AVR-Pita1 haplotypes were identified in avirulent isolates. AVR-Pik had four nucleotide sequence site changes resulting in amino acid substitutions, whereas three other AVR genes, AVR-Pizt, AVR-Pia, and AVR-Pii, were relatively stable. Two AVR genes, AVR-Pik and AVR-Pizt, were found to exist in relatively larger proportions of the tested field isolates, which suggested that their corresponding R genes Pi-k and Pi-zt can be deployed in preventing blast disease in the Southern UNITED STATES in addition to Pi-ta. This study demonstrates that continued AVR gene monitoring in the pathogen population is critical for ensuring the effectiveness of deployed blast R genes in commercial rice fields.

scholarly journals Characterization of Molecular Identity and Pathogenicity of Rice Blast Fungus in Hunan Province of China

Plant Disease ◽  
2017 ◽  
Vol 101 (4) ◽  
pp. 557-561 ◽  
Author(s):  
Junjie Xing ◽  
Yulin Jia ◽  
Zhirong Peng ◽  
Yinfeng Shi ◽  
Qiang He ◽  
...  
Keyword(s):  
Rice Blast ◽  
Blast Resistance ◽  
Pcr Amplification ◽  
Blast Disease ◽  
Hunan Province ◽  
R Genes ◽  
Rice Blast Resistance ◽  
Molecular Identity ◽  
Polymerase Chain

The blast (Magnaporthe oryzae) resistance (R) gene is the most economical and environmental method to control rice blast disease. Characterization of molecular identity and pathogenicity of M. oryzae benefits the deployment of effective blast R genes. In order to identify blast R genes that would be effective in Hunan Province,182 M. oryzae strains were analyzed with a Chinese differential system (CDS), repetitive element-based polymerase chain reaction (rep-PCR), and the presence and absence of avirulence (AVR) genes by PCR amplification with gene-specific primers. Identified blast R genes were validated with 24 monogenic lines (ML) carrying 24 major R genes. In total, 28 races (isolates) of M. oryzae was identified with CDS, and classified into 20 distinct groups with rep-PCR. Interestingly, AVR-Pia, AVR-Pik, AVR-Pizt, AVR-Pib, and AVR-Pi9 were detected in more than 86.8% of the isolates; AVR-Pita1 was in 51.3% and AVR-Pii was in only 2.5%. In contrast, pathogenicity assays on 24 ML demonstrated that Pi9, Piz5, Pikh, and Pikm were more effective, with resistant frequencies of 91.6, 91, 87.9, and 87.3%, respectively; Pia, Piks, Pit, Pi12, and Pib were less than 15%. These findings revealed the complexity of a genetic basis of rice blast resistance, and shed light on useful blast R genes in Hunan Province.

scholarly journals Pi64, Encoding a Novel CC-NBS-LRR Protein, Confers Resistance to Leaf and Neck Blast in Rice

2015 ◽  
Vol 28 (5) ◽  
pp. 558-568 ◽  
Author(s):  
Jian Ma ◽  
Cailin Lei ◽  
Xingtao Xu ◽  
Kun Hao ◽  
Jiulin Wang ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Rice Blast ◽  
Blast Resistance ◽  
Open Reading Frames ◽  
Chromosome 1 ◽  
R Genes ◽  
Repeat Proteins ◽  
Neck Blast ◽  
High Level ◽  
Lrr Protein

Rice blast caused by Magnaporthe oryzae poses a major threat to rice production worldwide. The utilization of host resistance (R) genes is considered to be the most effective and economic means to control rice blast. Here, we show that the japonica landrace Yangmaogu (YMG) displays a broader spectrum of resistance to blast isolates than other previously reported broad-spectrum resistant (BSR) cultivars. Genetic analysis suggested that YMG contains at least three major R genes. One gene, Pi64, which exhibits resistance to indica-sourced isolate CH43 and several other isolates, was mapped to a 43-kb interval on chromosome 1 of YMG. Two open reading frames (NBS-1 and NBS-2) encoding nucleotide-binding site and leucine-rich repeat proteins were short-listed as candidate genes for Pi64. Constructs containing each candidate gene were transformed into three susceptible japonica cultivars. Only transformants with NBS-2 conferred resistance to leaf and neck blast, validating the idea that NBS-2 represents the functional Pi64 gene. Pi64 is constitutively expressed at all development stages and in all tissues examined. Pi64 protein is localized in both the cytoplasm and nucleus. Furthermore, introgression of Pi64 into susceptible cultivars via gene transformation and marker-assisted selection conferred high-level and broad-spectrum leaf and neck blast resistance to indica-sourced isolates, demonstrating its potential utility in breeding BSR rice cultivars.

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