文冠果雌雄花比关联SSR和SNP的鉴定及种质资源评价

The wind-sand disaster is the most seriously ecological and environmental problem in China. On the other hand, the increasing demand for bioactive oils, which are being widely used in food, feed, health-promoting and medical products, can only be met by increased oil production. One way to achieve this is to increase oil yield of oil crops through screening the superior woody-oil trees, which could be adapted to harsh environments of deserts and arid regions...Yellow horn (Xanthoceras sorbifolia Bunge.) is an oil-rich seed shrub that belongs to the Sapindaceae family and has a life span of more than 200 years. It grows well in cold, barren environments and has great potential for biodiesel production. This species contains bioactive oils in its seeds, which have high contents of omega-6, omega-9 acids and nervonic acid. These oils are bioactive per se and also rich in other bioactive compounds with powerful nutritional and medicinal properties. Yellow horn is being grown on unproductive agricultural lands (e.g. desert, arid and semi-arid regions) in north of China. However, low seed production, which is from low ratio of female and male flowers (about 5-20%) and unknown relatives among germplasm, is seriously inhibiting the sustainable development of yellow horn industry. Later self-incompatibility occurs in this species, because all fruits from self-pollination are abortive in fruit growth and development process, and all ripen fruits are from cross-pollination...In this project, we will select pairs of plants with close relative relationship, which have significant differences in ratios of female to male flowers. Different floral organs will be collected in different periods of flower sex differentiation of selected plants. RNA-Seq technology will be used to discovery SSR and SNP markers of yellow horn. These SSR and SNP markers will be used to develop SSR and SNP fingerprinting for differentiating germplasm of candidate genes of flower sex differentiation in yellow horn with different ratios of female to male flowers, and identify genetic relationship among these germplasm. Then, based on the investigation on the ratios of female to male flowers and the analyses of SSR and SNP genotypes for large samples, SSR and SNP markers associated with high and low ratio of female to male flowers will be identified using the methods of candidate gene association analysis and multiple regression analysis of marker-trait association, respectively. These identified SSR and SNP markers will be used to identify and evaluate germaplasm, which will screen advanced materials for producing and breeding in the future...These results will provide molecular evidence for collection, conservation and varieties protection of yellow horn germplasm. It can also provide the fast and effective technology and method for identifying quality of the seedlings in the seedling stage, which can eliminate culled seedlings for avoiding from constructing low yield forest to lead economic and ecological loss. The results from this project can also provide scientific guide for constructing high-yield out-cross forest and for low-yield forest reconstruction. These have important significances for superior cultivars of yellow horn with high ratio of female to male flowers.

文冠果是我国荒漠防治和干旱区造林的重要木本油料能源树种。低雌雄花比和种质亲缘关系不清造成的低产正严重制约文冠果产业发展。本项目以近缘、雌雄花比存在明显差异的种质为对象，以花性别分化不同时期的不同花器官为材料，利用高通量mRNA-seq和qRT-PCR结合的方法，筛选与文冠果花性别分化相关的候选基因，开发候选基因的SSR和SNP标记，建立雌雄花比不同文冠果种质区分的SSR和SNP指纹图谱，鉴定不同种质间的遗传关系。然后，以雌雄花比存在广泛变异的种质构成大样本，对各单株进行SSR和SNP分析，利用候选基因关联分析和多元回归分析，鉴定与高和低雌雄花比关联的SNP和SSR标记，鉴评文冠果种质，筛选可用于生产和育种的高雌雄花比优质材料。这可为文冠果种质的收集、保存和品种保护提供分子证据，为苗期鉴定种质的优劣提供快速有效的技术方法，亦可为异交丰产林营造提供科学指导；对高雌雄花比文冠果育种具有重要意义。

文冠果是我国荒漠防治和干旱区造林的重要木本油料树种。低雌雄花比造成的低产正严重制约文冠果产业发展。项目以近缘、雌雄花比存在明显差异的种质为对象，以花性别分化不同时期的不同花器官为材料，利用高通量mRNA-seq和qRT-PCR结合的方法，筛选与文冠果花性别分化相关的候选基因，开发候选基因的SSR和SNP标记，建立雌雄花比不同文冠果种质区分的SSR和SNP指纹图谱，鉴定不同种质间的遗传关系。 RNA-seq开发出了文冠果花性状分化SSR标记35个，多元回归分析获得了3个与文冠果雌雄花比关联的SSR标记(XS_3304_1、XS_2159_3和XS_3197_5)：全基因组关联分析(GWAS）获得6个与文冠果雌雄花比关联的SNP标记，SNV25997070、SNV3954735、SNV10659705、SNV5194594、SNV29688046和SNV29815262，其遗传变异解释贡献率分别为7.19%、9.46%、9.95%、8.15%、7.5%和8.28%。鉴定出 CHS、DFR 、LAR、RPB4、LEA、CCNB1IP1、ABCF5、SAUR71、ARF19、ABF4和CKX7 基因可能对雌花发育有调控作用，PKSA、UBC2、MYC2、ANR 和 TKPR1 基因可能对雄花发育有调控作用。挖掘出 6 对调控雌性受体相关的miRNA-mRNA模块，包括 fve-miR159b/lus-miR159b-RPB4及aly-miR166g-5p -DHAD。发表研究论文7篇，其中SCI收录4篇(中科院SCI-2区4篇）、CSCD中文核心3篇；获授权发明专利1项、文冠果新品种2个(辽冠1号、辽冠8号)，培育文冠果良种2个(辽冠4号、辽冠8号)，制定地方标准3项；培养硕士研究生8名。