贵州喀斯特山区梨需冷量及休眠生理分子基础研究

Bud dormancy is the main obstacle for regulation of budbreak in fruit trees during the activity-dormancy-activity cycle. Bud can smoothly break when it only meet its chilling requirement through the dormancy. Pear is one of the most important deciduous fruit trees in the world. The present researches of bud dormancy have mainly focused on several genes for only physiological process, while few studies have been conducted for multiple physiological molecular process. So it is difficult to fully understand the physiological molecular mechanisms regulation for pear dormancy. Therefore based on the ecological environment in Guizhou Karst mountainous area, the characteristics of pear dormancy involved in chilling requirement, hormone metabolism, antioxidative metabolism, carbohydrate metabolism and protein metabolism will be analyzed for these cultivars ‘Huangli’ , ‘Haizili’, ‘Xueli’, ‘Cuiyu’, ‘Cuiguan’, ‘Wonhwang’ , and Pyrus pashia is one of the most important wild Pyrus species, growing in a wide range of habitats in Guizhou Province. Meanwhile, to better understand the molecular mechanisms, digital gene expression profiling analyses of bud will be conducted during the dormancy using the RNA-Seq technology . The number, function and expression pattern of differentially-expressed genes (DEGs) will be analyzed and compared, systematically screened dormancy-related genes. The relationship between the DEGs and its corresponding physiological metabolism will be ascertained, and what is the function of these genes will be investigated on dormancy maintain, release and regulation for pear buds.

在生长-休眠-生长的周期变化过程中，休眠作为限制果树萌芽期调控的主要因子，只有在休眠期间满足了一定需冷量，才能保证顺利通过休眠。梨在世界上广泛栽培，现有研究较多的集中在单一生理少数基因的传统思路上，而将多种生理分子过程结合起来的研究较少，难以从全局上认识梨休眠的生理分子调控机制。为此，基于贵州高原喀斯特山区生态环境条件下，以其著名的地方品种‘威宁黄梨’、‘兴义海子梨’和‘安顺雪梨’和贵州野生的梨属植物川梨以及近年引进贵州喀斯特山区栽培的‘翠玉’、‘翠冠’和‘圆黄’等品种为试材，全面系统地研究其需冷量和多种生理代谢（包括激素代谢、抗氧化代谢、碳水化合物代谢和蛋白质代谢等），应用RNA-Seq技术构建休眠期间梨芽数字基因表达谱文库，分析比较差异表达基因的数量、功能和表达模式，系统筛选休眠相关基因，探明梨休眠差异表达基因与其相应生理代谢的关系，揭示其对芽休眠维持、解除和调控有何作用。

梨是一种在全球范围广泛栽培的落叶果树之一，随着全球气候的变暖，许多果树（包括梨）受低温不足影响，进而影响其产业的可持续发展。基于贵州这种独特的高原喀斯特山区的生态环境条件下，梨的休眠特性还是一片空白。为此，本研究以‘黄梨’、‘海子梨’、‘翠冠’、‘圆黄’和‘秋锦’梨等为试材，分析了梨不同品种、梨花芽和叶芽的休眠状态、需冷量和生理代谢（抗氧化代谢、碳水化合物代谢、矿质营养元素和激素代谢等），利用RNA-Seq技术，全面系统地研究了梨芽休眠过程中基因转录的动态变化，探讨梨休眠的分子机制，主要结果如下：.1）.梨不同品种芽的休眠状态不同，同一品种花芽和叶芽的休眠状态也有不同。‘黄梨’花芽和‘翠冠’花芽在同一时间段解除内休眠，‘圆黄’和‘海子梨’花芽在同一时间段解除内休眠，所有梨品种花芽均没有表现深休眠。.2）.梨的需冷量随品种、生态条件、年际间、芽的性质和需冷量模型而不同。7.2 ℃模型和犹他模型显示‘翠冠’和‘圆黄’花芽和叶芽的需冷量相同,‘黄梨’叶芽需冷量比花芽高。.3）.‘黄梨’、‘海子梨’、‘翠冠’和‘圆黄’等不同品种花芽、叶芽和枝条在休眠进程中抗氧化代谢、碳水化合物代谢、矿质营养元素和激素代谢发生了不同的变化，且与休眠的解除有一定的关系。.4）.应用RNA-Seq技术构建‘黄梨’、‘海子梨’和‘翠冠’休眠进程中不同时期梨芽数字基因表达谱文库，进行差异基因系统筛选、聚类分析、GO、KEGG功能分析，探明3种梨基因型在不同休眠进程梨芽差异基因的数量、种类和功能上的差异，并对休眠进程中与编码低温相关蛋白基因、休眠相关基因（DAM）、抗氧化代谢相关基因和激素代谢相关基因与其相关代谢关系进行分析，揭示其可能对休眠维持和解除的作用。.本研究成果揭示了贵州喀斯特山区梨需冷量及休眠生理分子基础，对于丰富梨属植物的休眠特性具有十分重要的意义。完成并达到了项目研究的预期目标。