qSW.C9调控油菜种子重量（大小）的生物学功能与分子机理研究

单产的提高是我国油菜育种的长期目标，种子重量则是油菜单株产量的构成因子之一。项目组前期通过图位克隆分离到一个同时控制油菜种子重量和大小的QTL qSW.C9，该基因编码一个功能未知的RING型E3泛素连接酶。通过酵母双杂，已筛选出21个可能与SW.C9互作的蛋白。在此基础上，本项目拟：1）通过SW.C9的增强表达和基因敲除，并结合表型鉴定解析SW.C9的生物学功能；2）验证SW.C9的泛素连接酶活性，从互作蛋白中鉴定SW.C9的泛素化底物并在体内外予以验证；3）创建SW.C9及互作基因的双敲除突变体并分析其对粒重的遗传效应，结合转录组分析，筛选更下游的被调控基因，初步解析SW.C9调控种子重量的分子机制；4）利用SW.C9的优良单倍型改良骨干亲本材料并评价其育种价值。该研究结果将加深我们对油菜种子重量（大小）调控的理论认识，并为油菜产量遗传改良提供新的基因资源。

Increasing production per unit is a long-term breeding objective in rapeseed improvement, and seed weight (SW) is one of the three components determining plant yield. We previously identified and isolated a quantitative trait locus (QTL), qSW.C9, associated with seed weight. SW.C9 is predicted to encode a putative RING-type E3 ubiquitin ligase, and a screening based on yeast-two-hybridization indicated that at least 21 genes interact with SW.C9. In this project，we attempt to reveal the biological function of SW.C9 by investigating transgenic lines with enhanced expression of SW.C9 and with the SW.C9-trageted CRISPR knockout (1); and test the ubiquitin ligase activity of SW.C9 and identify its substrates of ubiquitination in vitro and in vivo (2); and predict the regulatory pathway mediated by SW.C9 by analyzing the transcriptome data and the genetic effects of double mutants of SW.C9 and its interacting or downstream genes (3); and improve the backbone parental lines with the elite SW.C9 haplotype through molecular marker-assisted selection (4). The research data from this project will enrich our theoretical understanding on molecular regulation of seed development and provides potential elite genes for the genetic improvement of rapeseed yield.