关键词: 水稻 , 突变体nfm1, 图位克隆, 光响应

Abstract: The heading stage of rice is an important agronomic trait, which determines the regional and seasonal adaptability of the variety, thus it was considered one of the main target traits by rice breeders. Although some of the major genes controlling rice heading stage have been cloned in the early researches, the identification of the regulatory factors controlling rice heading stage is still very limited. By screening the rice mutant library, a non-flowering mutant (nfm1) was obtained under long-day conditions (LD), and the mutant nfm1 was able to flower normally under short-day conditions. Using map-based cloning, the Nfm1 gene was located between two molecular markers, InDel1 and InDel2, in the 50 kb interval, which contained four genes. LOC_Os09g13740 was identified as a candidate gene for Nfm1 after sequence analysis. In the mutant nfm1, the serine at position 242 of the sixth exon of the LOC_Os09g13740 gene was mutated to isoleucine. The mutant nfm1 and the reported rice mutant lvp1-1 were alleles. The Nfm1 encoded a histone methyltransferase SDG724 containing the SET domain. It was noteworthy that under short-day conditions, the mutant nfm1 significantly increased the number of grains per panicle, indicating that the weak expression of the LOC_Os09g13740 gene might have potential production potential in the adapted ecoregion. Above results provided references for breeding rice varieties adapted to different ecological regions.

Key words: rice, nfm1 mutant, map-based cloning, light response