黄瓜长下胚轴基因lh1的图位克隆及其与短下胚轴基因sh1的互作研究

苗期徒长是黄瓜育苗过程中的常见难题，其直接原因是下胚轴的快速伸长。因此，了解下胚轴伸长的调控基因及其互作关系，对于解决黄瓜的苗期徒长具有十分重要的理论和实际意义。本项目以长下胚轴突变体149L、短下胚轴突变体西双版纳黄瓜以及两者的双突变体为研究材料，表型鉴定发现，双突变体的下胚轴长度和149L一致，这就说明长下胚轴基因lh1对短下胚轴基因sh1具有上位效应。我们在前期研究中已经成功克隆了短下胚轴基因sh1，并初步构建了sh1调控下胚轴伸长的基因网络模型。在此基础上，本项目将对长下胚轴基因lh1进行图位克隆，并采用qPCR、序列多样性分析、表达谱分析和基因互作分析等技术，构建lh1和sh1共同调控黄瓜下胚轴伸长的基因互作网络模型。该研究结果将为黄瓜的耐徒长育种提供直接可用的目标基因（分子标记）。同时，也将丰富人们对于下胚轴伸长理论的认识。

Leggy seedling is a common problem during the cucumber seedling production, which is caused by the hypocotyl fast elongation directly. Thus, understand the gene regulation and gene interaction during hypocotyl elongation will be very useful for us to solve this problem. Long hypocotyl mutant 149L, short hypocotyl mutant Xishuangbanna cucumber and the double mutant were used in this project, we found that the hypocotyl length of double mutant is the same with 149L, which means lh1 gene has an epistasis to sh1 gene. We already cloned the sh1 gene and build a gene network model of sh1 regulate the cucumber hypocotyl elongation. Based on these results, we will clone the lh1 gene and use qPCR analysis, gene sequence diversity analysis, gene expression profiling analysis and gene interaction analysis to build a gene interaction network model of the lh1 and sh1 regulate cucumber hypocotyl elongation together. The research result of the project will supply direct usable target gene (molecular marker) for the leggy tolerance breeding in cucumber. At the same time, it will also enrich our understanding on the hypocotyl elongation theory.