稀有变异揭示TCP基因调控黄瓜卷须发育

发布时间：2018-01-02 08:35

本文关键词：稀有变异揭示TCP基因调控黄瓜卷须发育　出处：《中国农业科学院》2016年博士论文　论文类型：学位论文

【摘要】：卷须是葫芦科瓜类作物株型研究最重要的方面之一,也是研究植物向触性运动的重要的植物模式器官。黄瓜的基因组、转录组和变异组的测序工作的完成,为系统研究黄瓜提供了大数据平台支持。本课题搜集了世界各地3342份黄瓜种质资源,发现唯一的一份无卷须的黄瓜资源CG9192,该种质的卷须被侧枝所替代,完全失去了攀援能力。我们推测该稀有表型是由稀有的遗传变异引起的。通过基因组学、变异组学和转录组学的综合分析,并应用稀有遗传变异的分析策略,我们发现了控制黄瓜卷须发育的身份基因CsTEN,并揭示了黄瓜卷须的同源器官是侧枝—这一曾经困扰达尔文的植物发育学谜团。本论文的主要结果如下：1.通过对变态卷须种质CG9192和正常卷须种质404的表型观察和扫描电镜分析,发现侧枝是黄瓜卷须的同源器官,遗传学研究表明变态卷须性状由一个隐性单基因控制(CsTEN)。2.稀有SNP在黄瓜四个亚群的分布不均匀,印度亚群拥有的稀有SNP数目最高,占所有稀有SNP数目的81%,印证了印度是黄瓜的起源中心。应用稀有变异分析策略,结合转录组数据,发现了变态卷须种质CG9192的一个稀有SNP (rSNPl)对应着一个在黄瓜卷须里特异表达的基因Csa5G644520,推测该基因可能是卷须的身份基因。3.构建遗传大群体,应用图位克隆的方法将候选基因CsTEN定位区间缩小至16Kb(区间内只有一个基因),并通过与核心种质的基因组重测序序列比对,发现只有发现的rSNP1可以解释变态卷须表型。针对rSNP1设计dCAPS标记,检测了世界范围内的、有卷须的1386份黄瓜种质,结果显示该稀有变异仅存在于黄瓜种质CG9192中,从而从遗传学上充分证明rSNP1所对应的基因Csa5G644520就是控制黄瓜卷须发育的基因CsTEN。4. CsTEN属于TCP家族的CYC/TB1亚类,CsTEN上的稀有SNP发生在葫芦科特有的保守结构域,该结构域不存在于已知的TCP蛋白中,该结构域是进化上新产生的一个结构域；烟草和酵母中的实验表明,该稀有SNP显著影响了CsTEN的转录激活活性。原位杂交分析进一步表明该CsTEN在黄瓜卷须里特异表达,是控制黄瓜卷须发育的身份基因。5.喷瓜是葫芦科植物中唯一没有卷须的植物,通过检测葫芦科卷须的身份基因TEN,发现喷瓜的TEN基因存在至少两个以上的提前终止变异,使得喷瓜的TEN基因完全失去了功能。6.构建了正常卷须和变态卷须的近等基因系,并将这对近等基因系进行转录组测序,发现CsTEN抑制叶和花等的侧生器官相关基因的表达,同时促进向触性运动相关基因的表达。
[Abstract]:Tendril is one of the most important aspects of plant type research in cucurbitaceae, and it is also an important plant model organ to study the thixotropic movement of plants, and the complete sequencing of cucumber genome, transcriptome and variation group. This paper collected 3342 cucumber germplasm resources from all over the world and found the only cucumber CG9192 without tendrils. The tendrils of the germplasm were replaced by lateral branches and lost the ability to climb completely. We speculate that the rare phenotype is caused by rare genetic variation. Using the analysis strategy of rare genetic variation, we found the identity gene CsTEN that controls the development of tendrils in cucumber. It also reveals that the homologous organ of cucumber tendrils is lateral branches-a phytodevelopmental mystery that once troubled Darwin. The main results of this paper are as follows:. 1. Phenotypic observation and scanning electron microscope analysis of metamorphosed tendrils (CG9192) and normal tendrils (404). It was found that lateral branches were the homologous organs of cucumber tendrils. Genetic studies showed that metamorphosis of tendrils was controlled by a single recessive gene, CsTEN. 2. The distribution of rare SNP in four subpopulations of cucumber was not uniform. India subgroup has the highest number of rare SNP, accounting for 81% of all rare SNP, which confirms that India is the origin center of cucumber. A rare SNP rSNP of CG9192, a metamorphosis tendrils, was found to correspond to a gene Csa5G644520 specifically expressed in cucumber tendrils. It is speculated that this gene may be an identity gene of tendrils. A large genetic population was constructed, and the mapping method was used to narrow the mapping interval of candidate gene CsTEN to 16kb (there was only one gene in the region). The results showed that only the rSNP1 could explain the phenotype of abnormal tendrils. DCAPS markers were designed for rSNP1 and detected in the world. There were 1386 cucumber germplasms with tendrils. The results showed that the rare variation existed only in the cucumber germplasm CG9192. Therefore, it is fully proved from genetics that the gene Csa5G644520 corresponding to rSNP1 is the gene CsTEN.4which controls the development of tendrils in cucumber. CsTEN belongs to the CYC/TB1 subclass of the TCP family. Rare SNP on CsTEN occurs in the conserved domain of Cucurbitaceae, which does not exist in known TCP proteins. Experiments in tobacco and yeast showed that the rare SNP significantly affected the transcriptional activation activity of CsTEN. In situ hybridization analysis showed that the CsTEN was specifically expressed in the tendrils of cucumber. It is the identity gene that controls the development of cucumber tendrils. 5. Spray melon is the only plant without tendrils in Cucurbitaceae. The identity gene TEN of tendrils of Cucurbitaceae is detected. It was found that there were at least two early termination mutations in the TEN gene of Spoux melon, which completely lost the function of TEN gene. 6. The near-isogenic lines of normal tendrils and metamorphosed tendrils were constructed. CsTEN inhibited the expression of genes related to lateral organs in leaves and flowers, and promoted the expression of genes associated with thixotropism.
【学位授予单位】：中国农业科学院
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S642.2

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