三七根际土壤细菌的群落结构与功能研究

发布时间：2018-04-28 08:57

本文选题：三七 + 根际土壤　；参考：《昆明理工大学》2017年硕士论文

【摘要】：三七是一种重要的经济和药用植物,但连作障碍严重。土壤微生物群落的变化被认为是三七死亡的主要原因,但对其变化规律和作用机理仍不清楚,因此系统研究三七栽种期微生物群落的变化情况,无疑具有重要意义。本文以不同季节,健康和生病,种植年限分别为1年、2年和3年的三七根际土壤样本为研究对象,在DNA和RNA水平对细菌群落结构和功能进行了研究。首先,提取三七根际土壤中微生物的总DNA后进行扩增子测序,对三七根际土壤细菌总群落进行研究。结果表明,三七根际土壤细菌具有很高的丰度和多样性。旱季样品的多样性高于雨季,生病三七高于健康三七。三七根际土壤中优势菌群为变形菌门、拟杆菌门、酸杆菌门、绿弯菌门和放线菌门。生病三七根际土中富集了大量的假单胞菌,Rickettsiaceae和amurshkyense。在功能上,生病与健康三七在氨基酸代谢合成、tRNA合成过程以及次生产物代谢方面存在差异。其次,提取三七根际土壤总RNA,对三七根际活跃细菌群落进行研究。结果显示,细菌活跃群落是总体群落的一个子集,不同样本中活跃的细菌群落不同,而不同的群落可能由不同的环境因素塑造。与健康三七相比,生病三七根际土壤活跃的细菌群落中独有的四个门是蓝藻门、拟杆菌门、放线菌门和酸杆菌门,其中芽孢杆菌属和Anoxybacillus属对其他细菌种群具有抑制作用。影响根际活跃细菌群落的主要环境因素是有机质速效氮速效钾磷速效磷。最后,利用宏基因组的方法开展了三七根际土壤中微生物群落组成和功能研究。三七根际土壤微生物主要参与碳水化合物代谢、氨基酸代谢、能量代谢、核酸代谢、辅因子和维生素合成代谢、复制与重组、膜运输等生化过程。生病三七根际土壤微生物在氨基酸代谢,环境因子响应和信号转导等方面的基因丰度升高了,生病三七根际土壤微生物对环境的适应性更强。三七根际土壤细菌群落在土壤氮循环、甲烷代谢和硫代谢方面具有重要作用,是三七根际土壤中化学循环的重要驱动力。本文系统的开展了三七根际土壤细菌群落结构及其功能研究,首次对三七根际活跃细菌群落进行研究,初步揭示了三七根际土壤细菌群落在连作过程中的演替规律,阐明了三七根际土壤微生物的生态功能。从土壤微生态学的角度为三七的可连续种植及其疾病控制提供了重要信息。
[Abstract]:Panax notoginseng is an important economic and medicinal plant, but continuous cropping obstacles are serious. The change of soil microbial community is considered to be the main cause of death of Panax notoginseng, but it is still unclear about its changing law and mechanism. Therefore, it is of great significance to systematically study the variation of microbial community in panax notoginseng during planting period. The structure and function of bacterial community were studied at DNA and RNA levels in rhizosphere soil samples of Panax notoginseng with different seasons, health and illness, and planting years of 1 year, 2 years and 3 years, respectively. Firstly, the total DNA from rhizosphere soil of Panax notoginseng was extracted and sequenced, and the total bacterial community in rhizosphere soil of Panax notoginseng was studied. The results showed that the rhizosphere bacteria of Panax notoginseng had high abundance and diversity. The diversity of dry season samples was higher than that of rainy season, and that of sick panax notoginseng was higher than that of healthy ones. The dominant bacteria in rhizosphere soil of Panax notoginseng were Proteus, Bacteroides, Acidobacterium, Chlorophyta and Actinomycetes. A large number of rickettsiaceae and amurshkyense. were enriched in the rhizosphere soil of Panax notoginseng. In function, there were differences between sick and healthy Panax notoginseng in amino acid metabolism, synthesis of tRNA and metabolism of secondary production. Secondly, total RNAs were extracted from rhizosphere soil of Panax notoginseng and the active bacterial communities in rhizosphere of Panax notoginseng were studied. The results showed that the active bacterial community was a subset of the total community. The active bacterial communities in different samples were different, but different communities might be shaped by different environmental factors. Compared with the healthy Panax notoginseng, the four unique phylum in the active rhizosphere soil community of Panax notoginseng were cyanobacteria, Bacteroides, actinomycetes and acidobacterium, among which Bacillus and Anoxybacillus had inhibitory effects on other bacterial populations. The main environmental factors affecting rhizosphere active bacteria community were organic matter available nitrogen, available potassium, available phosphorus. Finally, the composition and function of microbial community in rhizosphere soil of Panax notoginseng were studied by macrogenome method. Rhizosphere soil microorganisms of Panax notoginseng are mainly involved in carbohydrate metabolism, amino acid metabolism, energy metabolism, nucleic acid metabolism, cofactor and vitamin synthesis metabolism, replication and recombination, membrane transport and other biochemical processes. The gene abundance of soil microbes in diseased rhizosphere of Panax notoginseng increased in amino acid metabolism, environmental response and signal transduction, and the adaptability of soil microbes to environment was stronger in diseased rhizosphere of Panax notoginseng. Bacterial community in rhizosphere of Panax notoginseng plays an important role in nitrogen cycle, methane metabolism and sulfur metabolism, and is an important driving force of chemical cycle in rhizosphere soil of Panax notoginseng. In this paper, the structure and function of rhizosphere soil bacterial community of Panax notoginseng were systematically studied, and the active bacterial community in rhizosphere of Panax notoginseng was studied for the first time, and the succession of rhizosphere soil bacterial community of Panax notoginseng during continuous cropping was preliminarily revealed. The ecological function of rhizosphere soil microorganisms of Panax notoginseng was expounded. Soil microecology provides important information for continuous planting and disease control of Panax notoginseng.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S154.3;S567.236

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