基于遗传图谱和物理图谱的莲瓣形QTL定位及其基因挖掘

There are more than one thousand varieties of flower lotus for the genus Nelumbo Adans. which is one of the top 10 traditional flowers in China. Due to the simple type of the protospecies, be little accounted of normative and systematic breeding, and that it diverged from other eudicots early in eudicot history, the petal shapes of modern cultivars show low variability and severe lack of broad and slender petals is one evidence, which limit the ornamental value and its practical applications for flower lotus. Therefore, to explore novel cultivars with unique petal shapes will be a good idea to improve the industry of flower lotus... Using bulked segregant analysis (BSA) and molecular marker, we try to map QTLs about the trait of petal shape of flower lotus based on the F2 population from the cross of two inbred lines, the broad one and the slender one derived luckily from two Nelumbo lutea Pers. seedlings. We hope this research could be helpful to understand the mechanism of petal morphogenesis in the genus Nelumbo, and will facilitate the marker-assisted selection (MAS) in petal shape and molecular breeding.

莲是我国十大传统名花之一，观赏品种已达一千多个。由于原种类型单一、育种工作缺乏规范性和系统性以及其自身独特的进化属性等因素，现有莲品种的花瓣形状变异小，一直缺乏圆阔月季瓣类、丝状菊瓣类等极端瓣形性状，限制了莲的观赏性，在一定程度上制约着观赏莲产业的可持续发展。因此，以瓣形性状为突破点，创制独特瓣形观赏莲新种质，是提高莲观赏性及其应用价值的良好途径之一。.. 本研究拟以课题组新发现和制备的阔短瓣和狭长瓣美洲黄莲自交系构建F2群体，利用分离群体分组分析法和分子标记技术，实现瓣形性状QTL定位及其功能基因发掘，以期从分子水平初步阐明莲瓣形的发育机制，并为莲瓣形MAS育种和分子育种提供实用技术和基因储备。

现有观赏荷花品种的花被片形状（瓣形）变化小、多样性低，多为卵形、匙形或宽披针形等中间形状，开发阔短月季瓣类、狭长菊瓣类等极端形状品种有助于提升其产业竞争力。本研究以阔短瓣形美洲莲M512和狭长瓣形DP23及其F2群体为材料，解析瓣形性状的遗传规律及其QTL定位，以指导荷花瓣形定向育种。试验表明，美洲莲瓣形性状最适遗传模型为C-0模型，即瓣形性状受加性-显性-上位性多基因控制，其多基因遗传率为61.07%。利用133个SSR和EST-SSR标记构建了总图距402.8 cM的11个连锁群；共定位13个瓣形QTLs，其中10个比对到物理图谱上，QTL4和QTL9对应基因组序列在400Kb和300Kb范围之内。此10个QTLS共包含2243个注释基因和693个uncharacterized genes，以此为背景，结合全基因重测序技术和花蕾转录组比较差异表达基因，共检索获得重叠基因20个，作为今后研究荷花瓣形发育调控关注重点。此研究对了解高等开花植物花发育机制以及定向选育极端瓣形的观花植物具有参考价值。