茶树响应铝的遗传变异及铝富集候选基因挖掘

发布时间：2018-03-17 01:04

本文选题：茶树　切入点：遗传变异　出处：《华中农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：铝毒是酸性土壤中植物生长和作物生产的主要限制因素。茶树起源于我国西南地区,在亚热带、温带湿润的气候条件下,形成了“喜酸喜铝怕碱”的特性,其生长最适宜土壤pH为4.5-5.5,其铝含量是其它植物物种的几十倍,且没有任何铝毒害症状,表现出铝超富集的特性,表明茶树具有耐铝和铝富集机制,因此,明确茶树的耐铝和铝富集的机制,对于培育具有耐酸耐铝性的农作物、提高农作物产量及促进农业可持续发展具有非常重要意义。本试验明确了37份不同茶树基因型嫩梢的铝富集及根系生长响应不同铝浓度的遗传变异,挖掘了嘉茗1号茶树幼苗根系响应不同铝浓度(0 mM、0.2 mM、1.0 mM)的铝富集候选基因,分析了C2H2型锌指结构转录因子CsSTOP1在49份茶树基因型中的序列变异,结果如下:1.本试验采用营养液培养系统,设置0、0.2、0.4 mM Al浓度梯度,培养4个月后,测定了37份茶树基因型的铝浓度及根系生长的遗传变异。在0 m M Al浓度条件下,仅有福云6号、龙井43号、黔湄701、金牡丹4个基因型长出白色吸收根,占10.81%;在0.2 mM Al浓度条件下,24个茶树基因型长出白色新吸收根,占64.86%;在0.4 m M Al条件下,28个基因型长出白色新吸收根,占75.68%。结果表明,在适宜铝浓度范围内,铝促进茶树根系生长,0.4 mM Al促进作用大于0.2 mM Al。与不加铝相比,0.4 mM Al浓度处理后,25个茶树基因型的嫩梢铝浓度均有不同程度的增加,表明不同茶树基因型具有不同的铝吸收或分配存在广泛的遗传变异。2.为了挖掘与茶树耐铝或聚铝相关的候选基因,采用转录组对在0 mM、0.2mM、1.0 m M Al浓度处理条件下的嘉茗1号茶树幼苗根系进行转录组测序分析,共获得70.18 GB原始碱基序列数据,共组装了213699个高质量单基因簇(unigenes)。筛选得到不同类型的差异表达基因,主要包括转录因子、转运蛋白、氧化应激通路蛋白,以及涉及多糖和细胞壁代谢、能量和次级代谢、有机酸阴离子和酶分泌、三羧酸循环(TCA)调控、信号传导和生长激素生物合成代谢途径等基因,以上基因可能是茶树铝富集潜在候选基因。3.比对分析了49个茶树基因型的CsSTOP1基因序列,发现了63个单核苷酸(SNP)变异位点,其中33个位点的变异导致氨基酸发生改变,30个为同义变异,表明不同茶树基因型间CsSTOP1基因遗传变异丰富,还发现在5个茶树基因型(云南地方群体良种、云南大叶种、云抗27号、云茶普蕊、勐库大叶种)中CsSTOP1出现3个氨基酸序列的缺失,属于阿萨姆茶[C.sinensis var.Assamica(Masters)Kitamura]变种,该基因可能参与茶树耐铝聚铝的调控,这3个氨基酸的变异可能与茶树铝富集存在重要联系。
[Abstract]:Aluminum toxicity is the main limiting factor for plant growth and crop production in acidic soils. Tea trees originated in southwest China and formed "acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-acid-@@. The optimum soil pH was 4.5-5.5, and its aluminum content was several times higher than that of other plant species. Moreover, it had no symptoms of aluminum toxicity and showed the characteristics of aluminum superenrichment, which indicated that tea plants had the mechanism of aluminum tolerance and aluminum enrichment. To clarify the mechanism of aluminum tolerance and aluminum enrichment of tea plants, for the cultivation of acid- and aluminum-tolerant crops, It is very important to increase crop yield and promote the sustainable development of agriculture. In this experiment, the accumulation of aluminum in 37 tea genotypes and the genetic variation of different Al concentrations in response to root growth were determined. The candidate genes for aluminum enrichment in roots of Jiaming No. 1 tea seedlings responding to different aluminum concentrations (0 mm ~ 0 mm ~ (2) m ~ (2)) and 1.0 mm / m ~ (-1) were excavated. The sequence variation of zinc finger structure transcription factor (CsSTOP1) of C _ 2H _ 2 type in 49 tea genotypes was analyzed. The results were as follows: 1.The concentration gradient of 0.4 mm Al was set up in a nutrient solution culture system. After 4 months of culture, the Al concentration of 37 tea genotypes and the genetic variation of root growth were determined. Under the condition of 0 mm Al concentration, Only 4 genotypes of Fuyun 6, Longjing 43, Qianmai 701, Golden Peony grew white absorbing roots, accounting for 10.81%, and 24 tea genotypes grew white new absorbing roots under 0.2 mm Al concentration. Under the condition of 0.4 mm Al, 28 genotypes grew white new absorbing roots, accounting for 75.68%. The results showed that, in the suitable concentration range of aluminum, The effects of Al on root growth of tea plants were more than 0.2 mm Al. The concentrations of Al in the young shoots of 25 tea genotypes increased in varying degrees compared with those without Al addition. The results indicate that different tea genotypes have different aluminum uptake or distribution. 2. In order to mine candidate genes related to aluminum tolerance or polyaluminum tolerance in tea plants, The root system of tea seedling of Jiaming No. 1 was analyzed by transcriptome sequencing under the concentration of 0 mMM 0.2mMM + 1.0 mm Al, and 70.18GB primordial sequence data were obtained. A total of 213699 high quality single gene clusters were assembled. Different types of differentially expressed genes were screened, including transcription factors, transporters, oxidative stress pathway proteins, polysaccharide and cell wall metabolism, energy and secondary metabolism. Organic acid anion and enzyme secretion, tricarboxylic acid cycle TCA regulation, signal transduction and growth hormone biosynthesis pathway, The above genes may be potential candidate genes for aluminum enrichment in tea plants. The CsSTOP1 gene sequences of 49 tea genotypes were compared and 63 SNPs mutation sites were found. Among them, 33 loci caused amino acid changes and 30 were synonymous, indicating that the genetic variation of CsSTOP1 gene was abundant among different tea genotypes, and 5 tea genotypes (Yunnan local population, Yunnan large leaf species) were also found. There were three amino acid sequence deletions of CsSTOP1 in Yunkang 27, Yuncha Rui, Mengku leaf species), which belong to C. sinensis var.Assamica(Masters)Kitamura variety, and this gene may be involved in the regulation of aluminum polyaluminum tolerance in tea plants. The variation of these three amino acids may be related to aluminum enrichment in tea plants.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S571.1

【参考文献】