【作者】 于新宁；

【导师】 吕成群；

【作者基本信息】 广西大学 ， 生态学， 2005， 硕士

【摘要】 本工作从广西林业科学研究院和广西大学校园内6处不同地点采集小叶罗汉松和竹柏的根瘤,从中分离纯化得到23个菌株,均为杆状菌,革兰氏染色阴性,有鞭毛。根据芽孢的有无可将23个菌株初步分为2大细菌类群,即:13株不产芽孢类杆菌和10株产芽孢杆菌。按照杰明细菌鉴定手册,将2大类群细菌分别进行种属鉴定:13株不产芽孢类杆菌经过系统鉴定,以及结合其侵染豆科植物刺槐的途径研究与回接原宿主植物结瘤的研究,初步确定其中有2个菌株C4和C4Y41属于根瘤菌属细菌;10株产芽孢类杆菌通过传统表型分类法及16SrDNA编码序列同源性比较分析,结果与Bacillus subtilis有高达99%的同源性,因此我们鉴定该10个菌株为枯草芽孢杆菌。同时我们也将10株枯草芽孢杆菌接种到刺槐幼苗和原宿主植物幼苗上,结果发现,供试的10个菌株都可以侵染豆科植物刺槐结瘤,有50%的菌株能使接种后的植株生物量比不接种植株生物量要高,增加幅度0.05%—37.97%,从而可知,有部分的菌株对苗木的生长有一定的促进作用;供试的10个菌株也都可以侵染原宿主植物结瘤。本研究中,利用PCR技术作为基因克隆的重要手段,根据Genbank中nifA基因序列设计特异引物,PCR扩增出一段与Klebsiella pneumoniae nif gene cluster有99%的同源性的片断,可以作为筛选菌株C421R基因组文库中的探针。更多还原

【Abstract】 23 bacterium endophyte were isolated from the root nodule of Podocarpus brevifolius (Stapf) Foxw. and Podocarpus nagi from six different places in the campus of Guangxi University and research institute of forestry of Guangxi. They are pole form fungus, gram-negative, and they have flagellums. According to spore, all strains can be divided into two bacterium type groups: 13 bacterium do not have spore and 10 have spore. Based on Bergey’s Manual of Determinative Bacteriology, one herd of bacteria to be appraised: 13 bacterium producing spore were identified through experiment of systemic identification, combining they made Locust nodulation after inoculating and made various changes of locust roots and made original host nodulation. Among them, two strains (C4 and C4Y41 ) belong to Rhizobium finally; Based on phenotypic identification and 16S rDNA sequence analysis, 10 bacterium with spore were identified as Bacillus subtilis. At the same time we found that 10 strains of Bacillus subtilis made Locust nodulation after inoculating and made original host nodulation. Finally, 50% strains can make Locust increased weight with degree of 0.05%-37.97%, thus we can know, some strains have certainfacilitation to the growth of plant. With specific primer designed, PCR product nifA gene fragment was amplified by PCR. The fragment was sequenced and closely related to Klebsiella pneumoniae nif gene cluster with 99% overall similarity.更多还原