控制大豆荚粒数和叶型Ln基因的克隆和功能分析

Number seeds per pod and leaflet shape are important agronomic traits for soybean breeding. The single recessive locus "Ln", which causes increased number 4-seed per pod and narrow leaflet, has been elucidated and used in soybean breading for a long time. However, Ln gene has not been cloned, and it impedes to cognize the molecular mechanism controlling number seeds per pod and leaflet shape. Three independent mutants, allelic to Ln, had already been obtained from our gamma ray mutation population. The genetic and molecular study has characterized the candidate Ln gene in our previous work. In this project, we will confirm our previous Ln candidate gene by map-based cloning; reveal the function of Ln gene in controlling leaflet shape and number of seed pod; trace the molecular evolution pathway of Ln gene during soybean domestication; evaluate the breeding value of Ln gene in different cultivation conditions; and test the breeding possibility for genetic modified Ln gene. Above work will help us to comprehend the molecular mechanism controlling number seeds per pod and leaflet shape, and perceive the developmental mechanism to coordinate different organs in soybean.

每荚粒数性状和大豆叶型一直是大豆育种中重要的选择性状。控制四粒荚和窄叶的Ln基因很早就被人们所认识，并在育种实践中得到广泛应用；但Ln基因迄今尚未被克隆，已经影响了对大豆叶型和每荚粒数性状遗传机制的认知。申请者从伽玛辐射诱变群体中获得了3个Ln基因的等位突变体，初步基因定位研究确定了Ln基因的候选基因。本项目将利用图位克隆的策略克隆Ln基因；研究Ln基因在大豆叶形和荚粒数形成过程中的功能；分析Ln基因在大豆人工选择中的进化历程； 研究在不同栽培条件下,Ln基因对于大豆种子产量和质量的影响，明确Ln基因可能的育种价值；并利用基因工程的手段改变大豆荚粒数目和叶型，探索利用遗传工程改良大豆每荚粒数性状和大豆叶型的可能性。通过本项目的实施将会认识叶型和荚粒数调控分子机制，对于了解大豆调控不同器官协调发育的机理具有重要的推动作用。

本项目完成了大豆四粒荚和窄叶突变体ln的精细定位，克隆了大豆中的Ln基因；通过对“菏豆１２”全基因组重测序，检测到区别于公布的测序品种“Williams82”的插入缺失（InDels）位点 107,842个和单碱基多态性（SNP）位点 262,425个，开发了645对分子标记；对85个大豆品种的叶形和荚粒性状进行了定量分析，分析了这些大豆品种中Ln基因的多态性与叶形和荚粒性状之间的关系，为进一步研究Ln基因控制荚粒和叶片形态变化的分子机理提供了依据。