Fine mapping and cloning of Brown planthopper (BPH) resistance introgressed from Oryza nivara to O. sativa
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Date
2023
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Punjab Agricultural University
Abstract
Brown planthopper (Nilaparvata lugens Stål; BPH), is one of the major constraints of rice productivity in Southeast Asia. Here, we report fine mapping of a novel BPH resistance gene Bph34 from the wild species of rice Oryza nivara accession IRGC 104646 that localized to a 91 kb region of Nipponbare reference genome IRGSP-1.0 containing 11 candidate genes. Phenotypic screening of 250 F9 RIL population and 1000 F2:3 progenies against BPH biotype 4 revealed 1:1 and 1:2:1 segregating ratio, respectively and hence confirmed the single gene control of Bph34. Based on genotypic data of F9 population, we observed 26, 25, 2, 8, 11, and 11 recombinants at LOC_Os04g35180, LOC_Os04g35190, LOC_Os04g35210, LOC_Os04g35240, LOC_Os04g35260, and LOC_Os04g35280, respectively. This indicates that LOC_Os04g35210 stands out as a promising candidate among these 11 genes. Further, presence of only 3 breakpoints among F2:3 progenies robustly support the candidacy of LOC_Os04g35210 as Bph34. The qRT-PCR-based transcript abundance assay indicates a notable increase in the expression of LOC_Os04g35210 in resistant plants at 48 hours of post-BPH infestation. The sequencing of the coding domain sequence of the locus LOC_Os04g35210 indicated a single exon of 2706 bp in O. nivara and 2712 bp in PR122. A gene construct carrying CDS of Bph34 resistance gene was subjected to validation using colony PCR, plasmid PCR followed by double digestion of 6 positive plasmids. The recombinant plasmids with desired fragment size will be preceded for mobilisation into Agrobacterium strain and generation of T0 plants. Fundamentally, this research identifies and characterizes a novel Bph34 resistance gene, paving the way for its application in plant breeding initiatives.
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Pavneet Kaur (2023). Fine mapping and cloning of Brown planthopper (BPH) resistance introgressed from Oryza nivara to O. sativa (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.