甘蓝型油菜开花期的QTL定位及候选基因鉴定

QTL Mapping and Candidate Gene Identification of Brassica napus at Flowering Stage

为了解析油菜开花期性状的遗传机制,利用KN DH群体在冬性、半冬性和春性环境的开花期表型和KN高密度遗传连锁图谱,通过Wincart 2.5软件的符合区间作图法对油菜开花期性状进行QTL定位及候选基因鉴定。结果显示,共鉴定到119个开花期QTL,单个QTL解释表型变异最大是qFT-13DL16-4(25.96%),最小的是qFT-13ZY2-1(2.48%)。利用元分析的方法将初步鉴定的QTL整合为consensus QTL,共获得26个环境稳定表达QTL,包括7个开花期主效QTL。如cqFT-A2-3、cqFT-A2-4在春性环境稳定表达,cqFT-C6-4、cqFT-C6-7、cqFT-C6-12、cqFT-C6-13在冬性和半冬性环境稳定表达,cqFT-C6-14在冬性环境稳定表达QTL。主效QTL置信区间共鉴定到15个与成花诱导相关的候选基因,如 BnaA02g12260D(RGA1)、 BnaA02g15390D(AGL12)、 BnaA02g16710D(LKP2)和 BnaC06g19930D(NUA)等,这些候选基因主要涉及赤霉素、光周期、生物钟、春化作用响应和花发育等功能。可见,油菜开花期主效QTL及其候选基因的鉴定为开花期基因的精细定位和图位克隆奠定基础,也为培育早熟、高产油菜品种提供指导。

This study aimed to investigate the genetic mechanism of Brassica napus at flowering period using the double haploid(DH)population and KN population KN high-density genetic linkage map.The phenotype data at flowering period under winter,semi-winter and spring environments were analyzed by using composite interval mapping(CIM)of Wincart 2.5 software to locate the QTL for flowering-related traits and identify candidate genes.The results revealed a total of 119 associated with flowering stage,with qFT-13DL16-4 explaining up to 19.63%of the phenotypic variation(PV)and qFT-13ZY2-1 exhibiting the minimum PV(2.48%).Furthermore,these QTLs were integrated into a consensus QTL by meta-analysis,resulting in the identification of 26 environment-stable expression QTLs,including seven major QTLs.For example,cqFT-A2-3 and cqFT-A2-4 were stably expressed under the spring ecological environment,cqFT-C6-4,cqFT-C6-7,cqFT-C6-12,and cqFT-C6-13 were stably expressed in winter and semi-winter ecological regions,and cqFT-C6-14 was stably expressed in the winter ecological region.In conclusion,this study provides a foundation for fine mapping and map-based cloning of causal genes and offers guidance for the cultivation of new early maturing and high-yield rapeseed varieties in the future.Fifteen candidate genes involved in flowering regulation were identified within QTL confidence intervals,including BnaA02g12260D(RGA1),BnaA02g15390D(AGL12),BnaA02g16710D(LKP2)and BnaC06g19930D(NUA),and these candidate genes are involved in the regulatory pathways,such as gibberellin,photoperiod,circadian clock,vernalization response and flower development.In conclusion,this study lays a foundation for fine mapping and map-based cloning of causal genes and offers guidance for the cultivation of new early maturing and high-yield rapeseed varieties in the future.