外生菌根真菌（EMF）耐铬的生理与分子机制研究
时间:2018-07-10 10:34 来源:毕业论文 作者:毕业论文 点击:次
| 摘要：选用具有Cr耐性差异的两株Pisolithus属外生菌根真菌（Ectomycorrhizal fungi , EMF），研究了Cr处理对EMF菌株生长、菌液pH、真菌分泌的有机酸种类及分泌量、有机酸分泌关键酶活性等生理指标的影响。此外，实验对Cr处理前后的Cr耐性与敏感菌株进行了转录组分析，通过转录组分析和基因差异表达情况来研究调控耐Cr性状、参与Cr(VI)还原的分子机制。结果表明，EMF对Cr具有外质体屏障作用及一定的吸附能力，同时菌体可将Cr(VI)还原为Cr(III)，且在高浓度Cr胁迫下菌体可通过分泌草酸与Cr离子螯合的方式缓解毒害。而在后续的转录组分析中，我们还发现敏感菌株中316个基因特异性上调，综合前期实验现象推断这部分上调基因是关于高价铬还原的部分基因；同时根据对比两菌株基因变化差异，发现了耐受菌株中提高异柠檬酸裂解酶活性有关的48个基因。本研究结果为探究外生菌根真菌（EMF）耐Cr生理与分子机制提供了理论依据。25528 毕业论文关键词：外生菌根真菌；Cr胁迫；耐铬基因 Study on the Physiological and Molecular Mechanisms of Ectomycorrhizal Fungi Resistant Chromium Student majoring in National Life Science and Technique Talent-training Base Abstract: The effects of Cr treatment on the growth of EMF strain, the pH of fungi, the amount of organic acids secreted by fungi, the secretion and the key enzymes of organic acid secretion were studied in two strains of Pisolithus, which were different from Cr tolerance. The In addition, the Cr tolerance and the susceptible strains were analyzed before and after Cr treatment. The molecular mechanism of Cr (VI) reduction was studied by transcriptome analysis and gene differential expression. The results showed that EMF had the ability of Exoplasmic barrier and some adsorption capacity to Cr, and Cr (VI) could be reduced to Cr (III). At high concentration of Cr, the cells could be decomposed by oxalic acid and Cr Chelate the way to ease the poison. In the subsequent transcript group analysis, we also found that the 316 strains of specific strains of specific upregulation, comprehensive pre-experimental phenomenon concluded that this part of the up-regulated gene is on the high-priced chromium reduction part of the gene; at the same time according to the comparison of two strains of genetic differences, Resistant strains to increase isocitrate lyase activity related to 48 genes. The results of this study provide a theoretical basis for studying the physiological and molecular mechanisms of Cr resistance of ectomycorrhizal fungi Key words: Ectomycorrhizal Fungi; anti-chromium traits; gene expression 目 录 摘要…1 关键词1 Abstract …1 Key words1 1 材料与方法…2 1.1 实验材料…2 1.1.1外生菌根真菌菌株2 1.1.2培养基…2 1.2耐铬菌株的筛选及耐铬能力的测定2 1.2.1耐铬菌株的筛选2 1.2.2 Cr胁迫对耐性与敏感菌株生长的影响…2 1.3 EMF对Cr的吸收与Cr(VI)还原能力的探究…2 1.3.1菌液与样品液的配制…2 1.3.2总Cr的测定…3 1.3.3 Cr(VI)含量的测定…3 1.4 Cr处理后菌液pH的变化…3 1.5 Cr对EMF分泌低分子量有机酸的影响…3 1.6 Cr处理前后有机酸分泌关键酶活性的检测分析…3 1.6.1苹果酸脱氢酶…3 1.6.2异柠檬酸裂解酶3 1.7转录组测序4 2 结果与分析….4 2.1 Cr耐性菌株和敏感菌株的筛选4 2.2原生质膜对Cr的屏障与吸收作用…5 2.3 EMF对Cr(VI)的还原作用6 2.4 Cr对外生菌根真菌分泌有机酸的影响…7 2.5 Cr处理前后调控有机酸（草酸）分泌的关键酶活性的变化…7 2.5.1苹果酸脱氢酶…7 (责任编辑：qin) |