马铃薯加倍一倍体群体创建与块茎重量遗传分析

Potato is one of the most important crops both to China and the world, but little has been done with respect to gene/QTL mapping and cloning as the tetrasomic inheritance of potato is much too complicated. Doubled monoploid could be ideal material for potato research due to their homozygous diploid nature. Prickle pollination was made to cultivated potato 2392.092 with S. phureja and a self-compatible dihaploid ND37-7 with large tubers was obtained from the resulting gynogenesis population. The next step is to develop a doubled monoploid population of ND37-7 by anther culture followed by subsequent chromosome doubling with colchicine. We seek to find a self-compatible homozygous elite clone out of the doubled monoploid population. In addition, the major loci mediating tuber weight could be identified by combining BSA-seq and classical QTL mapping of the before-mentioned population. Our research will create proper materials for potato basic research, while providing insights into the genetic basis of tuber weight and guiding the selection of elite potato cultivars.

马铃薯是重要的粮食作物，但重要农艺性状控制基因/QTL研究较为滞后，主要原因是该作物四倍体遗传分析复杂。加倍一倍体（Doubled Monoploid）属纯合二倍体，是马铃薯生物学研究的理想材料。我们用授粉者S. phureja对四倍体栽培马铃薯2392.092进行诱导，并在孤雌生殖后代中筛选出自交亲和、块茎性状优良的双单倍体（Dihaploid）ND37-7，为通过二倍体的遗传分析方法定位功能基因提供了基础。下一步拟对ND37-7进行花药培养、染色体加倍以获得基因型纯合的加倍一倍体群体。从中选择自交亲和、块茎商品性状优良的克隆，作为马铃薯研究试验材料；采用BSA-seq与常规QTL定位相结合的方法，挖掘控制马铃薯块茎重量的主效遗传位点。本项目将为马铃薯相关研究创造试验材料，并为解析马铃薯块茎重量遗传机制和培育高产优质马铃薯新品种提供理论支撑。

马铃薯是我国重要的粮菜兼用作物。缺乏合适的遗传研究材料，是马铃薯基础研究和分子育种面临的突出问题。本项目以自交亲和的S. verrucosum为供体，通过花药培养创制用于马铃薯基础研究的模式材料，并通过构建F2分离群体和高密度遗传图谱，对块茎重量等关键农艺性状进行遗传定位。取得结果如下：建立并优化了S. verrucosum的花药培养体系，确定2mg/L NAA + 1mg/L 6-BA + 0.5mg/L KT + MS是最佳培养基，其对应的愈伤组织响应率为11.88%。通过花药培养获得80份再生材料构成的遗传群体，用流式细胞法对先期获得的23份材料进行倍性鉴定，发现6份为二倍体、17份为一倍体。利用22对SSR/Indel标记对6份再生二倍体进行纯合性鉴定，纯合概率为1-(1/2)^22 > 99.99%；结合表型评价和基因组重测序，筛选出2份纯合、自交结实性好、结薯正常的马铃薯二倍体新种质：SVA4和SVA32，可用作马铃薯功能基因研究的模式材料。对154个F2代分离单株（S. chacoense × S. tuberosum）进行低深度重测序，构建了包含1735个Bin标记的高密度遗传图谱，并在1、3、4、5号染色体各检测到1个控制马铃薯块茎重量的QTL位点，可解释块茎重量遗传变异的7.0% - 13.3%。综上，在本项目的支持下，创制了二倍体新种质SVA4和SVA32，为马铃薯基因发掘等基础研究提供了材料支撑；块茎重量QTL定位结果也为该性状候选基因挖掘和分子育种打下基础。