黄瓜果实黑刺基因定位及候选基因多样性研究

Gene Mapping and Candidate Gene Diversity of Black Spine on Fruit in Cucumber(Cucumis sativus L.)

果刺颜色影响黄瓜(Cucumis sativus L.)商品品质,是外观品质育种的重要性状之一。利用黄瓜黑刺自交系S52,黑刺野生种hardwickii以及3个白刺材料S1003、WI1983G和397为试材,分别构建BC1或F2遗传群体,对黄瓜黑刺性状(black spine,B)进行遗传分析与基因定位,并使用14个不同遗传背景的黑刺或白刺材料用于B候选基因Csa4G003095序列多样性研究。结果表明,S52、hardwickii中果实黑刺由显性单基因控制,利用3个群体均将B定位于第4染色体的短臂上,最近两侧翼标记(SSRB-130和SSRB-107)与B的遗传距离分别为2.01cM和0.78cM。序列分析发现,4个黑刺黄瓜材料的Csa4G003095预测编码的氨基酸序列没有差异,但10个白刺材料在该基因编码区的变异很大,引起其编码蛋白的一小段或大段氨基酸缺失,功能缺失造成了刺色变异,验证了Csa4G003095即为黄瓜黑刺基因B。同时,B基因侧翼标记InDelB01、SSRB-99、SSRB-130可用于黑刺辅助选择育种,准确率在97.9%以上。

Spine color has important influence on cucumber＇s commercial value. It is one of the important fruit exterior quality traits of cucumber. In this study, cucumber inbred lines $52, hardwickii （C. sativus vat. hardwicleii ） with black spine on fruit and S1003,WI1983G,397 with white spine were used to build 3 BC1/F2 populations for genetic analysis and mapping of black spine gene. Fourteen different genetic cucumber materials with different spine color were analyzed for diversity of candidate gene Csa4G003095. Genetic analysis showed that a single dominant nuclear gene,B （black spine）, determines the black spine trait in both S52 and hardwickii. Bulked segregation analysis （BSA） was performed in the 3 populations, BC1 [-（S52 × S1003） × S1003], F2 （S52）〈 Wl1983G）, Fe （hardwickii）〈 397）. B gene was mapped to a linkage group in each population, corresponding to the short arm of chromosome 4 of cucumber. The flanking markers （SSRB-130 and SSRP-107） of the map from F2 （S52）4 WI1983G） were linked to the B gene with genetic distances of 2.01 cM and 0. 78 cM, respectively. Sequence analysis found that all of 4 cucumber lines with normal Csa4GO03095 sequence had black spine, while the other 10 materials with abnormalCsa4GO03095 sequence had white spine. This phenomenon supports that Csa4GO03095 is the candidate of B gene. In addition,the flanking markers InDelB01,SSRB-99,SSRB-130 were used for MAS （maker assisted selection）. Their accuracy rates were higher than 97.9 %. This study provided an important foundation for breeding utilization and clarifying genetic mechanism of fruit spine color in eueNrnher