基于侯选基因标记的四倍体马铃薯休眠QTL关联分析

休眠期是马铃薯(SolanumtuberosumL.)重要的块茎性状之一,寻找调控马铃薯块茎休眠的关键基因,揭示其分子机制以选育具有适宜休眠期长度的马铃薯品种,对于解决当前马铃薯产业中过长或过短休眠期带来的经济损失和食品安全隐患等问题十分关键。前期研究在二倍体马铃薯连锁群体中定位了6个加性休眠QTL,本研究拟在四倍体马铃薯育种材料中验证这些休眠QTL。基于休眠QTL连锁的候选基因标记,采用混合线性模型(MLM),模型中考虑群体结构和亲缘关系(Q+K),在四倍体马铃薯自然群体St-hzau中对马铃薯块茎休眠期进行了关联分析。5号染色体上休眠QTL DorB5.3连锁的候选基因标记S199_300和GWD (根据葡聚糖水双激酶α-glucan water dikinase基因设计)与马铃薯块茎休眠期具有显著的关联(P0.05),分别解释了休眠期表型变异的7.8%和3.2%,分别能增加休眠期7.1 d和4.5 d,即在二倍体马铃薯连锁群体中定位的稳定主效休眠QTL DorB5.3在四倍体马铃薯关联群体St-hzau中也表现显著, DorB5.3的稳定性在关联分析结果中得到了验证,表明候选基因标记策略在马铃薯块茎休眠QTL关联分析中是一种有效的策略。本研究所验证的主效休眠QTL DorB5.3及相应连锁标记可以直接用于马铃薯休眠育种。据此可以推测GWD可能在控制还原糖含量和块茎休眠2个方面均发挥作用,马铃薯块茎休眠机制与还原糖含量变化机制可能存在着部分交叉。

Association analysis of dormancy QTL in tetraploid potato via candidate gene markers

Dormancy is one of the prominent and important potato (Solanum tuberosum L.) tuber traits. Identifying the key genes regulated potato tuber dormancy and revealing its molecular mechanism to select potato varieties with desirable dormancy length are crucial to solve the economic losses and food safety issues due to the unsuitable dormancy length in potato industry. Previously, six additive dormancy QTLs were mapped in a linkage population of diploid potato. This study aimed to verify these QTLs in tetraploid potato breeding germplasm. Based on the candidate gene markers linked to the dormancy QTLs, we used a mixed linear model (MLM), taking the population structure and genetic relationship (Q+K) into account to conduct the association analysis of potato tuber dormancy in a natural tetraploid potato population St-hzau. The candidate gene markers S199_300 and GWD (derived from α-glucan water dikinase gene) linked to QTL DorB5.3 on chromosome 5 showed significant association with potato tuber dormancy (P < 0.05), which explained 7.8% and 3.2% of the phenotypic variation, respectively. The two markers could increase the dormancy length by 7.1 d and 4.5 d, respectively, revealing that the main effect of dormancy QTL DorB5.3 in the linkage population of diploid potato was also significant in the natural tetraploid potato population St-hzau. So the stability of DorB5.3 was validated in the association analysis, showing that the candidate gene marker strategy is an effective strategy in QTL association analysis of potato tuber dormancy. The major dormancy QTL DorB5.3 and corresponding linkage markers verified in this study could be directly used in potato dormancy breeding. According to the results, it could be proposed that GWD might play a role in controlling reducing-sugar content and dormancy of potato tuber, indicating a mechanism crosstalk between potato tuber dormancy and reducing-sugar content.