昼夜周期调控淀粉积累起始的分子遗传学研究

Starch is generated with H2O oxidizationby and CO2 reduction by light energy absorbed by plant.Starch demand increases onrushingly alonnh with its use as biofeul and bio-material.It is increasingly urgent to meet starch demand through increasing starch accumulation in plant.Expension of duration for starch accumulation is no doubt alternative.Although starch biosynthesis pathway is almost clear,on the level of molecular biology how starch accumulation initiates in store organs is still unknow yet.In this study,an induction model for starch accumulation in potato tuber will be employed as starting material.With the model opening or closed genes expressing before and after initiation of starch accumulation (ISA) will be identified through transcript sequencing (RNAseq) as well as methods of bioinformatics and molecular biology. Initiation pathay for starch accumulation will be outlined based on the genes and progress on network of sugar/ diurnal/phytohormone signaling. The genes expressing on the upstream of the pathway (SAUR) will be confirmed by expression analysis.The full-length cDNA of those genes will be isolated. What initiation signals are and how SAURs response to the signals to induce starch accumulation will be definited.It is expected to disclose machanism that SAUR genes,responding to ISA signal,initiate starch accumulation to fill gap between starch accumulation and biosynthesis, and create new strategy for increase of starch with gene manipulation.

植物吸收光能，将H2O氧化CO2还原最终生成蓄能大分子-淀粉；随着淀粉在生物质能和材料领域应用的拓展，淀粉需求迅速上升；增加植物淀粉积累、以满足对淀粉需求的迅猛增长已迫在眉睫；延长植物生育期内淀粉积累时间无疑是理想的选择之一，尽管淀粉生物合成途径已基本清楚，但贮藏器官淀粉积累起始的分子生物学研究仍是空白；本研究旨在以本实验室获得的马铃薯淀粉积累起始诱导模型和glgC转化株系为材料，通过转录组测序、生物信息学和分子生物学等方法，识别昼夜周期诱导贮藏淀粉积累起始（SAI）前后开启或关闭表达的基因，结合糖、昼夜周期等信号网络的研究进展，绘制SAI途径草图；依表达分析确认SAI途径上游调控基因(SAUR)，分离其cDNA全长；表达分析明确SAI信号及SAUR如何响应信号诱导起始淀粉积累。研究预期揭示昼夜周期信号及其调控开启淀粉积累的机制，为通过延长淀粉积累时间增加其积累的基因操作创新思路。

按照申请书计划的研究内容，相继完成了不同光照周期处理马铃薯6个样品和对照的转录组测序、数据分析、目的基因筛选、表达定量测定、部分目的基因转化株系表型测定等研究工作；首次揭示了3个不同光照周期下分化表达基因，更为重要的是，GO富集分析发现，光合作用参与基因是不同光照周期诱导的主要响应基因，依据光照周期诱导目的基因表达量测定数据相关分析，筛选了光照周期响应节点基因，并依此识别和筛选了碳固定和淀粉积累上游起始基因；抑制其中部分基因体内表达的功能研究显示，光照周期响应基因极为广泛地参与了从器官发育和生育期到激素和叶绿体合成等基础代谢，最终调控淀粉积累。. 课题执行期间，新增成员教师2人，培养生物化学及分子生物学专业毕业研究生2名，完成生物技术专业本科生毕业论文3篇，撰写研究报告6篇，其中已发表署本课题编号3篇，待发表3篇，申请重组基因专利2项，获得淀粉积累增加马铃薯新种质2份；以本课题为主要依托，2014年获批宁夏马铃薯育种专项课题资助。研究达到了预期目的，实现了研究目标。