鄂尔多斯高原地区粘细菌的分离鉴定及其拮抗致病疫霉活性的初步分析

发布时间：2018-06-04 05:25

  本文选题：鄂尔多斯 + 乌海　； 参考：《内蒙古农业大学》2017年硕士论文

【摘要】：粘细菌(Myxobacteria)是一类比较特殊的革兰氏阴性真细菌,可以滑行运动,并且具有复杂多变的形态发生和种类多样的多细胞行为,能够通过营养细胞之间生物信号的相互感应与传递进行滑动、群体摄食以及形成特有的子实体和抗逆粘孢子,具有明显的社会性行为。由于粘细菌可产生丰富且结构新颖、种类多样、作用机制独特的次级代谢产物,所以其在抗病原真菌、细菌、抗病毒、抗肿瘤方面具有巨大的潜在应用价值,是一类有着极大的研究和实际开发价值的微生物类群。本论文的主要目的是开发新的粘细菌资源,从而获得抗马铃薯晚疫病活性较高的菌株和次级代谢产物。本研究按照土壤类型的不同设计采样计划,以采集自我国内蒙古自治区西部鄂尔多斯和乌海地区的46份土壤样品为研究对象,进行土壤微生物计数、土壤理化性质测定以及土壤粘细菌的分离纯化与鉴定,并对纯化菌株进行抗致病疫霉活性分析,对活性较高的菌株进行了发酵条件的优化。内蒙古西部鄂尔多斯和乌海地区微生物数量偏低,土壤pH呈中性偏碱性,绝大部分土壤存在旱情,土壤肥料含量也普遍较低。从46份土壤样品中富集分离出粘细菌191株,纯化出102株,分属5个属,11个种,其分别为:橙色粘球菌、黄色粘球菌、变绿粘球菌、叶柄粘球菌、珊瑚装珊瑚球菌、大孢珊瑚球菌、弱小珊瑚球菌、Pyxicoccus fallax、Cytobacter Violaceus、深褐孢囊杆菌、过度原囊菌。粘细菌的分布呈:林地草地耕地荒地。溶细菌类群、溶纤维素类群及粘细菌总数与土壤速效钾和有机质表现出显著的相关性,与有机质的相关系数分别达到0.690、0.543和0.732。72%的供试菌株对致病疫霉的生长产生不同程度的拮抗作用。拮抗效果最佳的为菌株E10、E11和E12,其抑菌直径分别达到:26、24、24 mm。菌株E10 为弱小珊瑚球菌(Corallococcws exigwows),菌株 E11 为匣状粘球菌(Pyxidicoccus fallax),菌株E12为珊瑚状珊瑚球菌(Corallococcus coralloiides)。菌株E10的最适发酵培养基为MX04(MD1),最适发酵条件为温度32 ℃,时间11 d,盐度0%;菌株E11的最适发酵培养基为MX01(VY/2),最适发酵条件为温度36℃,时间11 d,盐度0.5%;菌株E12的最适发酵培养基为MX04(MD1),最适发酵条件为温度32 ℃,时间111d,盐度0%;3株菌发酵液中拮抗致病疫霉生物活性物质均易溶于有机物,而难溶于水,大孔树脂可以在粘细菌的发酵过程中很好的吸附其产生的次级代谢产物。该工作的完成为抗马铃薯晚疫病生物农药的开发提供基础数据。
[Abstract]:Myxobacteria (Myxobacteria) is a special class of Gram-negative true bacteria that can glide and have complex morphogenesis and diverse multicellular behavior. It can glide through the mutual induction and transmission of biological signals between vegetative cells, feed on the population, and form special fruiting bodies and endospores, which has obvious social behavior. Because myxobacteria can produce abundant secondary metabolites with novel structure, various species and unique mechanism of action, they have great potential application value in resistant fungi, bacteria, anti-virus and anti-tumor. It is a kind of microorganism that has great research and practical development value. The main purpose of this paper is to develop new myxobacterium resources and to obtain high activity strains and secondary metabolites of potato late blight resistance. In this study, 46 soil samples from Ordos and Wuhai areas of Inner Mongolia Autonomous region were collected according to different soil type sampling plans, and soil microbial count was carried out. The physicochemical properties of soil and the isolation, purification and identification of soil myxobacteria were determined, and the anti-Phytophthora activity of the purified strains was analyzed. The fermentation conditions of the strains with higher activity were optimized. The amount of microbes in Ordos and Wuhai areas in western Inner Mongolia is low, the soil pH is neutral and alkaline, most of the soil exists drought, and the soil fertilizer content is generally low. 191 strains of myxobacteria were isolated from 46 soil samples, and 102 strains, belonging to 5 genera and 11 species, were isolated. Pyxicoccus fallaxa Cytobacter Violaceus, Bacillus fulminatum, Protosporium. The distribution of myxobacteria is as follows: woodland, grassland, cultivated land, wasteland. The number of soluble bacteria, cellulose and myxobacteria were significantly correlated with soil available potassium and organic matter. The correlation coefficient with organic matter reached 0.690%, 0.543% and 0.732.72%, respectively, which had different antagonistic effects on the growth of Phytophthora infestans. The antagonistic effects of E10 E11 and E12 were the best, and the inhibitory diameters of E10 E11 and E12 reached to 24 mm and 24 mm, respectively. Strain E10 was Corallococcws exigwowsm, strain E11 was Pyxidicoccus fallaxa and strain E12 was Corallococcus coralloiideschus. The optimum fermentation medium for strain E10 was MX04MMD1, and the optimum fermentation conditions were temperature 32 鈩，

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