大豆根构型近等基因系构建及相关基因克隆

Phosphorus (P) deficiency is a major limiting factor to soybean production. The root architecture of soybean is closely related to the efficient absorption and utilization of P. In this study, the two soybean varieties with significant differences from root architecture to P efficiency were hybridized to develop the recombinant inbred line population. And 7 important locus related to P uptake were detected under the low-P conditions. Backcross population with P efficient and superior root architecture were gotten in the BC3 population, by the way of phenotypic selection combined with molecular marker screening. On the above basis: (1) The near-isogenic lines (NILs) for root architecture related to P efficiency will be developed and evaluated by the advanced backcross method. (2) NILs were used to identify P-starvation responsive genes related to superior root architecture from the cDNA libraries constructed by the approach to genome wide search. (3)The differentially expressed genes related to superior root architecture for P efficiency will be screened by the way of Map-based cloning method. (4) The specific gene expression for root architecture with P efficiency will be attained by the comparison with the whole genome sequences of soybean. (5) functional analysis of candidate genes for root architecture with P efficiency by the way of functional complementation assay or RNAi method. The research results are of great ecological and economic significance for functional analysis of genes for root architecture with P efficiency, regulatory mechanism and adaptive mechanism by which soybean adapts to low P availability from the molecular levels, the breeding for P efficient with high P efficiency and superior root architecture to improve soybean yield, quality and resistance levels, and the maintenance of agricultural sustainable development.

土壤缺磷是大豆生产的一个重要障碍因素，大豆根构型与磷的高效吸收密切相关。但目前对低磷胁迫条件下磷高效根构型建成的分子机制鲜见报道。本项目在我们前期工作中，应用两个在磷效率和根构型方面具有显著差异的大豆品种杂交并构建重组自交系，在低磷条件下对大豆根构型相关性状进行了初步定位，采用高世代回交法获得磷高效根构型的BC3回交单株，在此基础上：（1）构建和评价磷高效根构型近等基因系；（2）采用全基因组扫描法精细定位磷高效根构型相关的目的基因；⑶采用图位克隆法分离磷高效根构型相关的目的基因；（4）借助大豆全基因组序列信息，通过序列比较、生物信息学分析磷高效根构型相关的候选基因；（5）通过功能互补试验或利用RNAi技术确定基因的功能。研究结果将阐明磷高效相关根构型的建成、调控机理以及对低磷胁迫的分子机制，为有效开展磷高效的根系性状育种利用，提高大豆产量、品质和抗性水平具有重要的生态和经济意义。

土壤缺磷是大豆生产的一个重要障碍因素，大豆根形态构型与磷的高效吸收密切相关。但目前对低磷胁迫条件下磷高效根构型建成的分子机制鲜见报道。本项目通过构建和评价磷高效根构型近等基因系，研究磷高效相关根形态构型的分子机制，获得以下重要结果：.（1）寻找并确定了21对磷高效相关根形态构型的特异性SSR标记，经水培试验验证，其符合率达到84%，筛选效率和准确性均显著优于田间试验；.（2）构建了包含5个株系326个单株的磷高效相关根形态构型的近等基因系，其主要农艺性状与受体BD2无差异，但在产量、根形态构型、磷养分、根系酸性磷酸酶活性、叶绿素含量等方面具有显著差异；.（3）低磷胁迫条件下NILs根系和叶片的IBA、IAA含量显著或者极显著高于对照BD2，说明根系生长素积累受缺磷信号强烈诱导；.（4）通过抑制缩减杂交（SSH）技术，从大豆根部克隆到一个编码AUX的基因，其开放阅读框有1833个核酸，编码610个氨基酸，推测为大豆生长素响应因子GmAux基因；.（5）利用NILs和轮回亲本进行磷胁迫条件下大豆根形态构型转录组分析，获得6776个差异表达基因，共获得366个与内源激素相关的基因，其中：生长素相关基因231个、乙烯相关基因3个、GA相关基因75个、ABA相关基因57个，为进一步进行生物信息分析和差异表达基因筛选奠定了基础；.（6）创建了以磷高效相关根形态构型近等基因系为媒介的大豆磷高效品种（系）遗传改良应用技术体系，育成了6个磷高效大豆新品种（系），审定大豆新品种1个，推荐审定新品种1个，农业部大豆品种权授权6个，申报并受理农业部品种权3个，并进行了新品种生产示范，申报并受理发明专利3项，发表论文4篇；.（7）研究结果初步阐明了磷高效根构型对低磷胁迫的响应机制，为进一步明晰磷高效的分子机制和有效开展磷高效的根形态构型育种利用，提高大豆产量，推动了绿色农业的发展，具有重要的生态和经济意义。