Abstract
Seed weight is a major target of peanut breeding as an important component of seed yield. However, relatively little is known about QTLs and candidate genes associated with seed weight in peanut. In this study, three major QTLs on chromosomes A05, B02 and B06 were determined by applying NGS-based QTL-seq approach for a RIL population. These three QTL regions have been successfully narrowed down through newly developed SNP and SSR markers based on traditional QTL mapping. Among these three QTL regions, qSWB06.3 exhibited stable expression with large contribution to phenotypic variance across all environments. Furthermore, RNA-seq were applied for early, middle and late stages of seed development, and differentially expression genes (DEGs) were identified in ubiquitin-proteasome pathway, serine/threonine protein pathway and signal transduction of hormones and transcription factors. Notably, DEGs at early stage were majorly related to regulating cell division, whereas DEGs at middle and late stages were mainly associated with cell expansion during seed development. Through integrating SNP variation, gene expression and functional annotation, candidate genes related to seed weight in qSWB06.3 were predicted and distinct expression pattern of those genes were exhibited using qRT-PCR. In addition, KASP-markers in qSWB06.3 were successfully validated in diverse peanut varieties and the alleles of parent Zhonghua16 in qSWB06.3 was associated with high seed weight. This suggested that qSWB06.3 was reliable and the markers in qSWB06.3 could be deployed in marker-assisted breeding to enhance seed weight. This study provided insights into the understanding of genetic and molecular mechanisms of seed weight in peanut.
QTL Mapping and Diurnal Transcriptome Analysis Identify Candidate Genes Regulating Brassica napus Flowering Time
