冷胁迫下哈密瓜基因表达谱及相关抗性酶分析

发布时间：2018-04-23 18:42

本文选题：哈密瓜 + 转录组　；参考：《石河子大学》2017年硕士论文

【摘要】：哈密瓜是新疆特色瓜果,采后贮藏过程中易发生冷害,造成很大经济损失。导致冷害的主要原因是贮藏中温度过低,因此适宜的贮藏温度是解决这一问题的关键。目前哈密瓜响应冷胁迫作用机制的研究较少,通过对哈密瓜转录组进行研究,通过分子手段研究哈密瓜关键基因的调控,为哈密瓜响应冷胁迫作用机制提供理论依据。目的:本实验研究了新疆哈密瓜早熟品种金皇后,通过研究3种贮藏温度(21℃、3℃和0.5℃)对哈密瓜果实采后品质及生理影响,并对不同条件的哈密瓜进行转录组测序,筛选出差异表达基因,对差异基因进行GO分析和Pathway分析等,从分子水平上研究哈密瓜在贮藏过程中可能存在的基因种类、功能及代谢途径等,提供哈密瓜响应冷胁迫作用机制的理论依据。方法:测定哈密瓜的生理指标,包括冷害指数、失重率、电导率、硬度和可溶性固形物,用试剂盒测定SOD、POD、CAT和CHT酶活性;利用BGISEQ-500测序平台对哈密瓜进行转录组测序。结果与结论:(1)0.5℃贮藏哈密瓜果实,能有效维持果实品质;延缓冷害指数、失重率和电导率的上升以及硬度、可溶性固形物含量下降;保持较高的SOD、POD、CAT、CHT的活性,延缓果实衰老、腐烂。(2)通过BGISEQ-500测序平台,平均得到24136070条原始reads,24105793条clean reads,clean reads与参考基因的平均比对率为64.22%,Clean reads与参考基因组平均比对率为80.67%。共鉴定到20823个基因,0.5℃的样品中鉴定到的基因数整体均少,而在21℃鉴定到的基因数整体均较多,说明低温抑制了哈密瓜在贮藏过程的代谢,抑制了基因表达,更有利于果实保鲜。(3)筛选出哈密瓜果实不同样品间的所有差异基因共15741个,进行GO功能注释,生物学过程显著富集的差异表达的基因在23条GO-term中,主要富集在代谢、细胞、单一生物三个过程中;细胞组分显著富集的差异表达的基因在16条GO-term中,主要富集在细胞、细胞部件和膜;分子功能显著富集的差异表达基因在13条GO-term中,主要富集在催化活性和结合。其中免疫调节、响应刺激、抗氧化活性和酶调节活性与冷胁迫相关。(4)哈密瓜果实中共有15741个差异表达基因,富集在134-131条通路中,显著富集的通路包括脂肪酸代谢、谷胱甘肽代谢、代谢途径、次生代谢产物生物合成、植物激素信号转导、植物病原菌的相互作用、淀粉蔗糖代谢、氨基酸生物合成、丙酮酸代谢、缬氨酸,亮氨酸和异亮氨酸降解等。
[Abstract]:Hami melon is a characteristic melon and fruit in Xinjiang. Cold damage is easy to occur during storage after harvest. The main cause of cold damage is low temperature in storage. Therefore, the key to solve this problem is the suitable storage temperature. At present, Hami melon response to cold stress mechanism is less, and the study of Hami melon transcriptional group is studied. Study on the regulation of Hami melon key genes by molecular means to provide a theoretical basis for Hami melon response to cold stress mechanism. Objective: this experiment studied the Xinjiang Hami melon early maturing variety gold queen, through the study of 3 storage temperatures (21, 3 and 0.5 C) on the fruit quality and physiological effects of Hami melon after harvest, and to different conditions of HA. The transcriptional group was sequenced, the differentially expressed genes were screened, the differentially genes were analyzed by GO analysis and Pathway analysis. The possible genetic types, functions and metabolic pathways of Hami Melon during storage were studied at the molecular level, and the theoretical basis of the mechanism of Hami melon in response to cold stress was provided. Indexes, including the cold damage index, weight loss rate, electrical conductivity, hardness and soluble solid, the activity of SOD, POD, CAT and CHT enzyme were measured with kits, and the transcriptional group of Hami melon was sequenced using BGISEQ-500 sequencing platform. Results and conclusions: (1) storage of Hami melon fruit at 0.5 degrees can effectively maintain fruit quality; delay the cold damage index, weight loss rate and electrical conductivity Rising and hardness, the content of soluble solids decreased; maintained high activity of SOD, POD, CAT, CHT, and delayed fruit senescence and decay. (2) the average ratio of 24136070 original reads, 24105793 clean reads, clean reads to reference basis was 64.22%, Clean reads and the average ratio of the reference genome. The total number of genes identified in the samples of the rate of 80.67%. was 20823. The number of genes identified in the samples at 0.5 C was less, and the number of genes identified at 21 C were all more, indicating that low temperature inhibited the metabolism of Hami melon in the storage process, inhibited the gene expression and was more conducive to the preservation of the fruit. (3) all the differences between the different fruits of Hami melon were screened. A total of 15741 different genes were annotated by the GO function. The differentially expressed genes in the biological processes were significantly enriched in 23 GO-term, mainly enriched in the three processes of metabolism, cells and single organisms; the differentially expressed genes in the cell components were significantly enriched in 16 GO-term, mainly enriched in cells, cell parts and membranes; the function of the molecules was significantly rich. The differentially expressed genes in the 13 GO-term were mainly concentrated in the catalytic activity and binding. The immunoregulation, response stimulation, antioxidant activity and enzyme regulation activity were related to cold stress. (4) there were 15741 differentially expressed genes in Hami melon fruits, enriched in 134-131 pathways, and the significant enrichment pathways included fatty acid metabolism and cereal caspine. Peptide metabolism, metabolic pathway, biosynthesis of secondary metabolites, plant hormone signal transduction, plant pathogen interaction, starch sucrose metabolism, amino acid biosynthesis, pyruvate metabolism, valine, leucine and isoleucine degradation, etc.

【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S652.1

【参考文献】