基因印迹对油菜种子发育中油脂累积作用的研究

To increase the rapeseed oil content is the key of increasing the production benefit of rapeseed, the high oil content has become the importance objective of rapeseed breeding now or in future. The many research results have indicated that the rapeseed oil content is controlled not only by maternal genetype,but also by embryo genetype and plasmatic inheritance.The gene imprinting is a hot field of plant epigenetics research recently，only involving maize and Arabidopsis thaliana and rice, some research results have indicated that the development of embryo and endosperm and matter accumulation in seed. but there are few report about studies on the gene imprinting in developmental process of rape seed. In this project, using modern molecular biology methods, timely and spatial regular of the gene imprinting in developmental process of rape seed and different gene imprinting of reciprocal crossbred between higher oil-content parent and lower oil-content parent will be studied, and the function of imprinted genes will be analysed, so that the effect of the gene imprinting on the oil accumulation in rape seed will be clarified. This project could contribute to clarify the mechanism of rapeseed oil content and to provide theoretical guide for the high oil-content cultivation and the high oil-content breeding.

提高菜籽的含油量是当前提高油菜生产效益的关键，高含油量已成为现在或将来油菜育种的重要目标。许多研究表明油菜种子的含油量不仅受母体基因型控制，还受胚基因型、细胞质效应的控制。基因印迹是近年来植物表观遗传研究的一个热门领域，只涉及到玉米、拟南芥、水稻，研究结果表明基因印迹调控着种子的胚和胚乳的发育及干物质积累。但对于油菜还没有相关的研究报道。本项目是采用现代分子生物学手段研究油菜种子发育过程中基因印迹的时空规律和含油量极端（36.27%、52.14%）的2个亲本正反交种子发育过程中基因印迹差异及印迹基因的功能分析，以便探明基因印迹对油菜种子油脂累积的作用，为解析油菜高含油量的分子机制提供依据，从而为油菜高含油量育种和高含油量栽培提供理论指导。

提高菜籽的含油量是当前提高油菜生产效益的关键，高含油量已成为现在或将来油菜育种的重要目标。油菜含油量具有严重的偏母性，这可能是母体基因型影响（角果皮光合作用）、细胞质效应、杂种胚的基因印迹等因素引起的。本研究以甘蓝型油菜DH0216（含油量为52.14%）和DH0729（含油量为36.27%）为材料，对基因印迹解释油菜含油量偏母性的分子机制进行研究。发现DH0216和DH0729正反交种子的含油量具有显著的偏母性；转录组分析10DAF正反交种子油脂累积通路上基因表达差异，挖掘出95个候选印迹基因；RT-PCR验证其中gene38713（acyl-acyl carrier protein thioesterase ATL3）、gene44160（B3 domain- containing protein）、gene70506 (transcription factor MYB30-like)、gene18158 (acyl-coenzyme A oxidase 2)表现出印迹基因表达模式；qPCR检测表明 gene44160、Gene70506，Gene18158在正反交杂种中呈现出一致的表达模式，在20DAF的前期杂种中它们处于印迹表达模式，在30DAF的后期杂种中处于非印迹表达模式，其中gene70506和gene18158在30DAF之后的正反交杂种子叶中表达差异显著，S16-29的高于S29-16的。这暗示了它们对油菜种子含油量的偏母性有一定的作用。印迹基因启动子的DNA甲基化分析表明其启动子在亲本种子、正反交种子中DNA甲基化呈现出差异，特别10DAF种子的启动子甲基化差异显著，这说明了启动子甲基化差异可能是基因印迹的原因之一，从而通过印迹基因表达不同影响正反交种子含油量，导致菜籽含油量的偏母性。综述所述，基因印迹是油菜含油量偏母性的原因之一，为揭示油菜含油量的分子机制及高含油量育种提供依据和理论指导。