Dataset Information

The OsOXO2, OsOXO3 and OsOXO4 Positively Regulate Panicle Blast Resistance in Rice.

ABSTRACT:

Background

Although panicle blast is more destructive to yield loss than leaf blast in rice, the cloned genes that function in panicle blast resistance are still very limited and the molecular mechanisms underlying panicle blast resistance remain largely unknown.

Results

In the present study, we have confirmed that the three Oxalate oxidase (OXO) genes, OsOXO2, OsOXO3 and OsOXO4 from a blast-resistant cultivar BC10 function in panicle blast resistance in rice. The expression of OsOXO2, OsOXO3 and OsOXO4 were induced by panicle blast inoculation. Subcellular localization analysis revealed that the three OXO proteins are all localized in the nucleus and cytoplasm. Simultaneous silencing of OsOXO2, OsOXO3 and OsOXO4 decreased rice resistance to panicle blast, whereas the OsOXO2, OsOXO3 and OsOXO4 overexpression rice plants individually showed enhanced panicle blast resistance. More H₂O₂ and higher expression levels of PR genes were observed in the overexpressing plants than in the control plants, while the silencing plants exhibited less H₂O₂ and lower expression levels of PR genes compared to the control plants. Moreover, phytohormone treatment and the phytohormone signaling related gene expression analysis showed that panicle blast resistance mediated by the three OXO genes was associated with the activation of JA and ABA signaling pathways but suppression of SA signaling pathway.

Conclusion

OsOXO2, OsOXO3 and OsOXO4 positively regulate panicle blast resistance in rice. The OXO genes could modulate the accumulation of H₂O₂ and expression levels of PR gene in plants. Moreover, the OXO genes mediated panicle blast resistance could be regulated by ABA, SA and JA, and may be associated with the activation of JA and ABA signaling pathways but suppression of the SA signaling pathway.

SUBMITTER: Dong J

PROVIDER: S-EPMC8179873 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND:Rice blast is a destructive disease caused by Magnaporthe oryzae, and it has a large impact on rice production worldwide. Compared with leaf blast resistance, our understanding of panicle blast resistance is limited, with only one panicle blast resistance gene, Pb1, isolated so far. The japonica cultivar Miyazakimochi shows resistance to panicle blast, yet the genetic components accounting for this resistance remain to be determined. RESULTS:In this study, we evaluated the panicle blast resistance of populations derived from a cross between Miyazakimochi and the Bikei 22 cultivar, which is susceptible to both leaf and panicle blast. The phenotypic analyses revealed no correlation between panicle blast resistance and leaf blast resistance. Quantitative trait locus (QTL) analysis of 158 recombinant inbred lines using 112 developed genome-wide and 35 previously reported polymerase chain reaction (PCR) markers revealed the presence of two QTLs conferring panicle blast resistance in Miyazakimochi: a major QTL, qPbm11, on chromosome 11; and a minor QTL, qPbm9, on chromosome 9. To clarify the contribution of these QTLs to panicle blast resistance, 24 lines homozygous for each QTL were selected from 2,818 progeny of a BC2F7 backcrossed population, and characterized for disease phenotypes. The panicle blast resistance of the lines harboring qPbm11 was very similar to the resistant donor parental cultivar Miyazakimochi, whereas the contribution of qPbm9 to the resistance was small. Genotyping of the BC2F7 individuals highlighted the overlap between the qPbm11 region and a locus of the panicle blast resistance gene, Pb1. Reverse transcriptase PCR analysis revealed that the Pb1 transcript was absent in the panicles of Miyazakimochi, demonstrating that qPbm11 is a novel genetic component of panicle blast resistance. CONCLUSIONS:This study revealed that Miyazakimochi harbors a novel panicle blast resistance controlled mainly by the major QTL qPbm11. qPbm11 is distinct from Pb1 and could be a genetic source for breeding panicle blast resistance, and will improve understanding of the molecular basis of host resistance to panicle blast.

Project description:BACKGROUND:Rice blast caused by Magnaporthe oryzae is the most devastating disease in rice production. Compared with seedling blast, panicle blast is considered to be more destructive, which can occur without being preceded by severe seedling blast. However, panicle blast resistance research is rarely reported. RESULTS:Bodao, a japonica landrace from Taihu Lake region, showed a high level of panicle blast resistance. In this study, a mapping population of 212 recombination inbreeding lines (RILs) was developed from a cross of Bodao and the susceptible cultivar Suyunuo, and the RILs were evaluated for panicle blast resistance in three trials. Two quantitative trait loci (QTLs) qPb11-1 and qPb6-1 for panicle-blast resistance were identified, including a major QTL qPb11-1 (Pb-bd1) on chromosome 11 of Bodao explaining from 55.31% to 71.68% of the phenotype variance, and a minor QTL qPb6-1 on chromosome 6 of Suyunuo explaining from 3.54% to 6.98% of the phenotype variance. With the various segregation populations, Pb-bd1 was fine mapped in a 40.6 Kb region flanked by markers BS83 and BS98, and six candidate genes were identified within this region, including one gene encoding NAC domain-containing protein, one gene encoding unknown expression proteins, two genes encoding nucleotide binding site-leucine rich repeat (NBS-LRR) type disease resistance proteins, and two genes encoding von Willebrand factor type A (VWA) domain containing proteins. For application in rice breeding, three introgression lines of Pb-bd1with significantly enhanced panicle blast resistance were developed by using molecular assisted method (MAS) from the commercial variety Nanjing46 (NJ46). CONCLUSION:Two QTLs, qPb11-1(Pb-bd1) and qPb6-1 conferring panicle blast resistance, were identified from japonica landrace Bodao and Suyunuo.qPb11-1(Pb-bd1) was fine mapped in a 40.6 Kb region flanked by marker BS83 and BS98. Three introgression lines of Pb-bd1with significantly enhanced panicle blast resistance were developed by MAS method from the commercial variety NJ46. It indicated that Pb-bd1 would be useful gene source in panicle blast resistance breeding.