芦笋矮秆基因da1的精细定位与矮秆种质创制

Asparagus officinalis L is known as "the king of vegetables". The asparagus plants are very tall and liable to lodging, causing yield loss to this industry. Farming practices of topping and making anti-lodging brackets are often required for the production of asparagus. Asparagus dwarf breeding will greatly improve the harvest index of asparagus with contribution to the ideal plant type and prevention of lodging, and also simplify the farming operation for its production. However, there is no report on dwarf breeding of asparagus up to now probably due to the lack of genetic resources. Asparagus dauricus Fisch.ex Link is one of closely related specie to asparagus officinalis L, with some valuable traits especially dwarf. We collected this precious wild species in North China and succesfully crossed it with an asparagus cultivar TN3 through interspecific hybridization. F1 and F2 populations are established. In this study, a major nuclear gene da1 controlling the dwarf trait will be identified and fine mapped with a fine genetic and physical mapping using the populations. At the same time，more than 200 new DNA molecular markers such as InDel, SNP and SSR will be developed, which are around the targeted area and evenly distrisbuted in the genome of asparagus. Research will be conducted on some important agronomic traits, morphological and cytological characteristics of the stalk of the populations with combinations of techniques of backcrossing, anther culture and molecular mark assistant selection. This will help better understanding of the dwarfing mechanism of da1 gene in asparagus and enhance genetic improvement of asparagus in plant heigh with expectation on creation of the first dwarf germplasm in asparagus offcianalis L.

"蔬菜之王"的芦笋，成龄植株高大，生产上常需摘顶和搭防倒伏支架，若矮化育种，既可塑造理想株型提高收获指数，还可防倒伏。目前国内外尚无芦笋株高遗传改良研究报道。我们将芦笋野生资源矮生性近缘种兴安天门冬与芦笋栽培种TN3成功进行了种间杂交并获得后代，建立了F1、F2群体。本研究拟以该群体为试验材料，在遗传分析发现芦笋矮秆基因da1基础上，进一步扩大F2作图群体，对芦笋矮秆基因da1进行精细定位，开发覆盖芦笋基因组与定位区域的InDel、SNP等新型分子标记，构建围绕da1的精细遗传图谱和物理图谱，为da1克隆与基因功能分析作准备。同时，为了挖掘利用兴安天门冬优良矮生性状，从形态学、细胞学对其农艺性状、茎秆的形态特征与细胞学特性进行比较研究，并以F1、F2等为育种材料，通过杂交、回交与自交，利用与da1紧密连锁的DNA分子标记进行辅助选择，结合花培技术，创造和培育遗传上稳定的芦笋矮秆种质或品系。

本项目将芦笋矮生性的近缘野生种兴安天门冬与芦笋栽培种TN3种间杂交F2群体作为矮秆基因（QTLs）定位群体，构建了总长677.96cM遗传图谱，定位4个主效QTL位点，单个QTL 位点的可解释的表型变异范围为13.3046%- 19.1663 %。 同时，利用芦笋基因组测序组装数据，在全基因组开发70，082对SSR引物，构建了芦笋基因组SSR数据库AGSSR；基于同源基因克隆策略，在芦笋基因组上预测获得具有高置信度的株高同源基因位点16个，根据保守序列开发32个分子标记对F2群体进行检测，结果发现，标记R16_1扩增的长1054bp片段与高秆表型表现共分离，存在显著遗传相关性，R16_1所对应的同源基因位点Aof001644.1与控制水稻理想株型的主基因（IPA1）序列高度相似，二者均含有一个SBP基序，根据生物信息学分析结果，预测Aof001644.1是芦笋株型基因，调控株高，作为本项目da1的候选基因位点。此外，农艺性状与细胞学分析发现，节间缩短是兴安天门冬矮生的主要原因，而兴安天门冬节间短主要是由于细胞数量减少所引起的；通过通过杂交、回交与自交等技术手段，已创制获得趋于稳定的矮秆种质材料。本项目将为后续芦笋矮化育种提供了大量的矮秆种质材料和全基因组DNA分子标记，也为芦笋矮秆基因克隆与矮化分子遗传机理研究奠定了基础。本项目共发表相关研究期刊论文5篇，会议论文2篇，获得国家发明专利1项，培养在读博士1名，总体上完成了研究目标。在项目执行期间成功主持召开第13届世界芦笋大会，以及芦笋基因组计划国际合作项目“芦笋基因组测序分析”研讨会，为本项目后续深入研究提供了很好的技术信息资源和国际合作交流平台。.