番茄Dicer-like 2 亚家族基因的功能分析

Dicer-like proteins (DCLs) are a small protein family in plants and key components in the small RNA biogenesis pathways. They play important roles in growth, development and responses to various biotic and abiotic stresses. These DCL proteins have functional diversification. Even in rice (Oryza sativa) two homologs of DCL3 gene: OsDCL3a and OsDCL3b,showed differently expression level and play different roles. Four DCL2 (SlDCL2a,2b,2c,2d) genes were identified in Solanum lycopersicum (tomato) and this is first time to find four paralogies of DCL2 subfamily. Previous studies indicated that expression pattern of SIDCL2s gene were not similar and suggesting their function might be divergent. In this project, we will clone and isolate the full-length coding sequences of SlDCL2s. Using RNAi, the expression levels of SlDCl2s will be suppressed separately or co-suppressed. The morphological changes, physiological characteristics and storability of transgenic tomato lines and even related gene expression levels will be analyzed. These results will reveal the roles of DCL2s in tomato and offer some foundations on their regulation mechanism. This project will help better understand the biological roles of DCL2s.?Moveover，transgenic tomato lines will be infected with viruses and even viruses gene expression levels and siRNA of host will be check. These results will reveal the roles of DCLs of tomato and offer some foundations on their regulation mechanism. This project will help better understand the biological roles of DCLs.

植物DCLs是一个小蛋白家族，参与小RNA的生成，在植物生长发育及抗胁迫等过程中有着重要作用。不同的DCL功能不同。水稻OsDCL3亚家族中两个同源蛋白OsDCL3a,3b的研究也表明它们的表达模式不同，蛋白功能出现分化上。番茄基因组上鉴定4个同源的DCL2，这时首次在同一物种上找到4个旁系同源的DCL2基因，它们的功能尚不清楚。我们前期的研究表明它们的表达模式各不相同，暗示它们的功能可能有所区别。本研究拟以番茄为材料，获得4个DCL2基因（SlDCL2a-2b）全长cDNA序列；通过RNAi单基因沉默或共沉默SlDCL2s。分析转基因株系生长发育、果实形成和耐贮性等特征，检测相关基因的表达；同时采用番茄易感病毒感染转基因番茄，检测宿主中病毒mRNA和病毒来源的siRNA来确定SlDCL2s剪切外源病毒的分子功能，揭示DCLs在调控植物的生长发育、果实成熟，抗病型和耐贮性过程的作用。