蒙古黄芪对干旱胁迫的响应及分子应答机制研究

发布时间：2018-01-01 23:27

本文关键词：蒙古黄芪对干旱胁迫的响应及分子应答机制研究　出处：《内蒙古大学》2016年博士论文　论文类型：学位论文

【摘要】：干旱是中国西北部面临的一个主要问题,严重影响着当地经济和生产的发展。寻找抗旱植物或研究当地植物的抗旱机制对解决干旱问题有着重要的意义。蒙古黄芪[Astragalus membranaceus Bge.var. mongolicus (Bge.)Hsiao]为重要的中药材,以根入药,目前在中国的西北部地区广泛种植。本研究以蒙古黄芪为实验材料,研究了干旱胁迫对二年生蒙古黄芪盆栽苗生长、生理生化指标及次生代谢产物积累的影响,并结合代谢组学(1H-NMR)和转录学(Illumina Hiseq 2000)探究了黄芪对干旱胁迫响应的分子机制。此外,研究了适度干旱胁迫对三年生蒙古黄芪盆栽苗生长及品质的影响,研究了叶面喷施外源性水杨酸对二年生蒙古黄芪抗旱性的影响。研究结果如下：1.在14天持续性干旱胁迫过程中,由于土壤相对含水量的降低,叶片相对含水量(RWC)和生物量均呈现不同程度降低。轻度和中度干旱时,黄芪体内一些抗氧化酶类的活性增强,渗透调节物质脯氨酸和可溶性糖含量增多。但重度胁迫时,抗氧化酶类活性减弱甚至消失。一定程度范围内的干旱胁迫,能提高黄芪甲苷,毛蕊异黄酮葡萄糖苷、芒柄花苷、毛蕊异黄酮和芒柄花素4种黄酮类成分的含量。2.代谢组学分析表明,干旱显著地影响了代谢的过程,主成分分析(PCA)显示蔗糖、脯氨酸和苹果酸为差异代谢物,特别是脯氨酸,在重度干旱胁迫下,含量较对照增加了近60倍。重要的代谢通路,糖酵解途径、三羧酸循环、谷氨酸介导的脯氨酸合成通路、蔗糖和淀粉代谢途径均不同程度受到了干旱胁迫的影响。3.转录组测序发现,干旱胁迫后黄芪根中大量转录本发生了变化,和对照相比较,轻度干旱、中度干旱和重度干旱分别有18,292,15,085和20,986差异表达基因,与干旱相关基因P5CS,PDH,MDH,锌指蛋白基因和细胞色素P450s相关基因在不同程度干旱胁迫下表达量不同。4.在适度干旱胁迫下,两个不同种源黄芪的生物量均降低,但次生代谢产物黄芪甲苷,毛蕊异黄酮葡萄糖苷、芒柄花苷、毛蕊异黄酮和芒柄花素4种黄酮类成分的含量有不同程度地增加。5.叶片喷施一定浓度水杨酸后,在干旱胁迫第10天时,抗氧化酶类活性与干旱组相比达到最大,渗透调节物质明显增多,比干旱组有更高的叶片RWC,叶片水势,叶绿素含量,更低地电解质渗透率和丙二醛含量,表明水杨酸在黄芪的抗旱性方面发挥了一定作用。
[Abstract]:Drought is a major problem facing northwest China. The development of local economy and production is seriously affected. It is important to find drought-resistant plants or study the drought-resistant mechanism of local plants in order to solve the drought problem. Astragalus mongolicus (Astragalus mongolicus). [Astragalus membranaceus Bge.var. mongolicus Bge.Hsiao is an important traditional Chinese medicine. Astragalus mongolicus (Astragalus mongolicus) was used as experimental material to study the effects of drought stress on the growth, physiological and biochemical indexes and the accumulation of secondary metabolites of biannual Astragalus mongolicus seedlings. The molecular mechanism of Astragalus membranaceus in response to drought stress was investigated by means of 1H-NMRs and Illumina Hiseq 2000. The effects of moderate drought stress on the growth and quality of three year old Astragalus mongolicus seedlings were studied. The effects of exogenous salicylic acid sprayed on leaves on drought resistance of biennial Astragalus mongolicus were studied. The results were as follows: 1. During 14 days of persistent drought stress, the relative water content of soil decreased. Leaf relative water content (RWC) and biomass decreased in varying degrees. During mild and moderate drought, the activities of some antioxidant enzymes in Astragalus membranaceus were increased. The content of proline and soluble sugar increased, but the activity of antioxidant enzymes decreased or even disappeared under severe stress. Contents of isoflavone glucoside, anthocyanin, isoflavone and anthocyanin. 2. Metabolic analysis showed that drought significantly affected the metabolic process. Principal component analysis (PCA) showed that sucrose, proline and malic acid were different metabolites, especially proline, under severe drought stress, the content of sucrose, proline and malic acid increased nearly 60 times compared with the control. Glycolysis pathway, tricarboxylic acid cycle, glutamate mediated proline synthesis pathway, sucrose and starch metabolism pathway were all affected by drought stress. After drought stress, a large number of transcripts in the root of Astragalus membranaceus changed. Compared with the control, the numbers of light drought, moderate drought and severe drought were 180.292 and 15085 and 20, respectively. 986 differentially expressed gene and drought related gene P5CSN PDHG MDH. The expression of zinc finger protein gene and cytochrome P450s related gene were different under different degrees of drought stress. Under moderate drought stress, the biomass of two different provenances of Astragalus membranaceus decreased. But the secondary metabolites, astragaloside, isoflavone glucoside and anthocyanin. The contents of isoflavones and Flos mandshurica were increased to some extent. 5. The leaves were sprayed with certain concentration of salicylic acid on the 10th day of drought stress. Compared with the drought group, the antioxidant enzyme activity reached the maximum, osmotic regulator increased significantly, higher leaf RWC, leaf water potential, chlorophyll content, lower electrolyte permeability and malondialdehyde content than the drought group. The results showed that salicylic acid played a certain role in the drought resistance of Astragalus membranaceus.
【学位授予单位】：内蒙古大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q945.78

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