【摘要】 【目的】为了探究非豆科植物泡桐与微生物共生固氮体系,对泡桐根瘤内生细菌的分离培养条件及其系统发育地位进行初步研究。【方法】对从广西钦州市采集的泡桐根瘤上分离纯化得到的根瘤内生细菌,进行传统生理生化研究和16S rDNA系统发育分析。【结果】经分离纯化得到9株根瘤内生细菌,大部分菌株能较好地利用8种碳源;78%的菌株能利用铵盐,89%的菌株能利用硝酸盐;所有的供试菌株在3-酮基乳糖和淀粉水解试验中呈阴性;89%的菌株能利用柠檬酸盐;B.T.B反应除菌株PG-7产碱外,其余都产酸;33%的菌株能使硝酸盐还原;有56%的菌株能在牛肉膏蛋白胨培养基上生长良好,多数菌株具备豆科植物根瘤菌的一般生理生化特征。通过16S rDNA全序列分析,确定9株供试菌株可分为4个菌属,其中菌株PG-1和PG-2共属于土壤杆菌属(Agrobacterium),PG-3、PG-5、PG-6、PG-8和PG-9等5株菌株共属于根瘤菌属(Rhizobium),PG-4隶属于草螺菌属(Herbaspirillum),PG-7隶属于伯克氏菌属(Burkholderia)。【结论】分离自同一寄主的根瘤内生细菌其生理生化特性方面存在较大的差异性,同时表现出了遗传的多样性。更多还原

【Abstract】 【Objective】In order to explore the symbiotic nitrogen fixation system of non-leguminous plants Paulownia and microorganism, a preliminary study was carried out on isolated culture conditions and the phylogenetic position of endophyic bacteria in Paulowia root nodules.【Method】The endophytic bacteria isolated and purified from the root nodules of Paulownia collected from Qinzhou of Guangxi Province were subjected to traditional physiological and biochemical studies and 16 S rDNA phylogenetic analysis.【Result】In the nine strains of endophytic bacteria isolated and purified, most of the bacterial strains could make good use of 8 carbon sources; 78% of the bacterial strains could use ammonium salt, and 89% of the bacterial strains could use nitrate. All tested bacterial strains were negative in the 3-ketolactose and starch hydrolysis test; 89% of the strains could use citrate. Except that the bacterial strains PG-7 produced alkali, the rest of bacterial strains produced acid in the B.T.B reaction; 33% of the strains could reduce nitrate; 56% of the strains grew well on beef extract peptone medium, and most strains have the general physiological and biochemical characteristics of leguminous rhizobium after identification. According to 16 S rDNA complete sequence analysis, nine bacterial strains can be divided into four bacteria genera, among which the bacterial stains PG-1 and PG-2 belong to Agrobacterium, PG-3, PG-5, PG-6, PG-8 and PG-9 belong to Rhizobium, PG-4 belongs to Herbaspirillum and PG-7 belongs to Burkholderia.【Conclusion】The endophytic bacteria isolated from the same root nodule have great differences in their physiological and biochemical characteristics of endogenous bacteria, and showed genetic diversity.更多还原