水稻穗基部退化位点qPBD3的定位OA

Panicle degeneration in rice reduces the number of grains per panicle and single plant yield,highlighting the significance of investigating genes associated with panicle degeneration for the molecular breeding of rice.In this study,phenomena of panicle basal degeneration and segregation in the F2 population derived from the cross between rice variety Nagina22(N22)and LIU XU were observed.Through bulked segregant analysis sequencing(BSA-seq)and single marker analysis(SMA),a quantitative trait locus(QTL)for panicle basal degeneration was mapped to chromosome 3 and designated as qPBD3.On the basis of the results from multi-year repeated experiments,this QTL was further finely mapped to the interval 12.8～13.1 Mb,with a size of approximately 273 kb.This interval harbored 22 genes with homology between N22 and LIU XU,and expression profiling revealed that 7 genes exhibited high expression in young panicles.The functional annotation of homologous genes and sequence alignment analysis between parents showed that LOC_Os03g22540.1 was a homologous gene of the panicle development regulatory gene OsJMJ706.There was a non-synonymous amino acid mutation locus in its coding sequence(CDS),while a frameshift mutation occurred in the CDS of LOC_Os03g22720.1,leading to the premature termination of the encoded protein.Therefore,these two genes were identified as candidate genes of qPBD3.The fine mapping of a QTL for panicle basal degeneration not only provided a new locus for molecular marker-assisted selection breeding of rice with panicle degeneration but also laid a foundation for delving into the genetic regulatory mechanism of panicle basal degeneration in rice.