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【目的】了解对荒漠环境有良好适应性的白皮锦鸡儿种子可培养内生细菌的多样性。【方法】采用种子表面灭菌、种皮与种仁分离、可培养细菌分离纯化、对p H及盐的耐受性、16S r RNA基因序列扩增和系统发育分析进行系统研究。【结果】从白皮锦鸡儿成熟种子种皮和种仁分别分离纯化到6株和26株内生细菌,其中分离自种皮的菌株最适p H均在9.0以上,且有3株最高可耐受p H 14.0,有5株可耐受10%的Na Cl;分离自种仁的菌株p H耐受范围明显低于种皮,但有12株对Na Cl的耐受性可达10%。16S r RNA基因序列分析显示,30株与芽孢杆菌属(Bacillus sp.)接近,相似率95%-99%,其中13株与枯草芽孢杆菌(Bacillus subtilis)的相似率为96%-99%,11株与地衣芽孢杆菌(Bacillus licheniformis)相似率为95%-99%;1株与单孢菌属(Sphingomonas sp.)相似性为99%,1株与大肠杆菌属(Escherichia sp.)相似性为98%。【结论】白皮锦鸡儿种仁内生菌数量和种类均高于种皮,体现出其可培养内生菌在空间分布的分异性及种类的多样性,且推测其种皮内生菌对盐碱的高度耐受性应与其环境适应性相关。
【Objective】 To understand the diversity of endophytic bacteria cultivated in Caragana microphylla which has good adaptability to desert environment. 【Method】 Separation and purification of cultivated bacteria, tolerance to p H and salt, 16S rRNA gene sequence amplification and phylogenetic analysis were systematically studied on the surface of seeds by using the method of seed surface sterilization. 【Result】 Six strains and 26 strains of endophytic bacteria were isolated and purified from the seed coat and seed kernel of mature seed of Caragana korshinskii respectively. Among them, the optimum p H values of strains isolated from seed coat were above 9.0, and three strains were the highest Tolerate p H 14.0, 5 strains tolerated 10% NaCl; strains isolated from seed kernel p H tolerance was significantly lower than the seed coat, but 12 strains Na Cl tolerance up to 10% . The sequence analysis of 16S rRNA showed that 30 strains were close to Bacillus sp., The similarity rate was 95% -99%, of which 13 strains were similar to Bacillus subtilis 96% -99% The similarity between 11 strains and Bacillus licheniformis was 95% -99%. The similarity between 1 strain and Sphingomonas sp. Was 99%, and 1 strain was similar to Escherichia sp. 98%. 【Conclusion】 The numbers and types of endophytic bacteria in Caragana microphylla were higher than that in the seed coat, which showed the diversity and species diversity of the endophytic bacteria in their cultivars. The high tolerance of salinity should be related to its environmental adaptability.