春兰是我国特色传统兰花的典型代表，具有极高的观赏价值。春兰需要5-10℃低温环境解除花芽休眠促进开花，但其分子机制尚不清楚。申请人前期工作发现，春兰在成花起始两个月后将进入生长停滞期，至少40天低温处理才能解除花芽生长抑制。此过程与春化途径有显著时空差异，可能存在物种特异的调控机制。通过转录组比较分析，新发现一个CgSVP基因在低温处理春兰休眠花芽后表达受到强烈抑制，而该基因的过表达则导致开花明显延迟。这表明CgSVP参与低温解除花芽休眠后促进开花过程。本项目将结合发育生物学和分子生物学手段，通过分析CgSVP基因功能、鉴定CgSVP上游调控因子以及相互作用蛋白，研究CgSVP对春兰独特的低温依赖开花过程的调控作用及其分子机理，为今后利用基因工程技术调控春兰以及其它兰科植物开花提供理论基础。

Cymbidium goeringii, which is also named spring orchid, is a very famous traditional orchid plant in China, with a high ornamental value. They need 5-10 ℃ cold condition to release flower bud dormancy and promote flowering. However, the mechanism underlying its cold-dependent regulation of flowering is unclear. Our previous study on flowering physiology indicated that the flower bud will enter the growth retardation period in two months after floral initiation, and at least 40 days at low temperature can relieve this growth inhibition. There is a significant spatial and temporal difference between this process and the vernalization pathway, which probably resulted from a specific regulatory mechanism. Though comparative transcriptome analysis, we found that the expression of a new SVP gene, CgSVP, is strongly suppressed and overexpression of CgSVP leads to a significant delay in flower development and opening, which indicated that CgSVP is involved in cold-induced release of flower bud dormancy of C. goeringii. On this basis, this project will deeply analyze the functional mechanism of CgSVP using the technical methods of developmental biology and molecular biology, to reveal the biological function of CgSVP and determine protein-protein interaction of CgSVP. Combining with the response to upstream low-temperature signals and the regulation of downstream flowering genes, we will finally clarify the regulatory mechanism of CgSVP during the process of low-temperature induced flowering, which would provide valuable data and practical guidance for flowering regulation and molecular breeding of C.goeringii and other orchid plants as well.