Genome-wide characterization of SDR gene family and its potential role in seed dormancy of Brassica napus L

Abstract

Rapeseed (Brassica napus L.) with short or no dormancy period are easy to germinate before harvest (pre-harvest sprouting, PHS). PHS has seriously decreased seed weight and oil content of B. napus. short-chain dehydrogenase/ reductase (SDR) genes have been found to related to seed dormancy in rice and Arabidopsis by promoting ABA biosynthesis. In order to clarify whether SDR genes are the key factor of seed dormancy in B. napus, homology sequence blast, protein physicochemical properties, conserved motif, gene structure, cis-acting element, and gene expression analysis were conducted in present study. Results shown that 142 SDR genes, unevenly distributed on 19 chromosomes, has been identified in B. napus genome. Among them, four SDR clusters present in chromosome A04、A05、C03、C04 were also identified. These 142 SDR genes were divided into four subfamilies on phylogenetic tree. Members of the same subgroup have similar protein character, conserved motifs, gene structure, cis-acting elements and tissue expression profile. Specially, the expression levels of genes in subgroup A and D were gradually decreased, but greatly fluctuated in subgroup B with the development of seeds. However, the expression levels of three genes in subgroup C and four genes in group B were rapidly raised at the late stage of seed development (64 days after flowering). Mostly, we explored four seed dormancy related candidate genes which were significantly higher expressed in weak dormancy seeds than that in nondormancy seeds. These findings provide a key information for investigating the function of BnaSDR on seed dormancy in B. napus.