山苍子（Litsea cubeba）可培养内生细菌的多样性

【目的】研究山苍子可培养内生细菌的多样性。【方法】利用添加植物组织浸提液的营养琼脂培养基分离山苍子根、茎、叶及果实中的可培养内生细菌，采用16S rDNA序列鉴定法对分离获得的山苍子可培养内生细菌进行鉴定。同一组织内，对16S rDNA序列及形态完全一样的菌株合并冗余，用Clustalx对分离得到的菌株16S rDNA进行排序，构建NeighborJoining系统进化树，并计算Jaccard指数和多样性指数。【结果】 共分离得到52株山苍子可培养内生细菌（根23株、茎8株、叶7株、果实14株），分属于芽孢杆菌属（Bacillus）、类芽孢杆菌属（Paenibacillus）、Paenochrobactrum、普罗威登斯菌属（Providencia）、假单胞菌属（Pseudomonas）、鞘氨醇单胞菌属（Sphingomonas）和Lysinibacillus共7个属的16个种，其中芽孢杆菌属细菌40株，与Bacillus tequilensis、解淀粉芽孢杆菌（Bacillus amyloliquefaciens）、苏云金芽孢杆菌（Bacillus thuringiensis）3个种最接近的内生细菌占分离细菌株数的69.2%；根及果实中的可培养内生细菌数量及种属均最丰富，其多样性指数高于茎、叶；叶与果实可培养内生细菌的Jaccard指数最高，达0.56，其余均较低。【结论】山苍子可培养内生细菌在植株内部的分布既有种属特异性，又有器官相似性。

Phylogenetic diversity of cultivable endophytic bacteria isolated from Litsea cubeba

【Objective】 The study was done in order to study the diversity of endophytic bacteria in Litsea cubeba.【Method】 We took nutrient agar medium amplified by the water extract of Litsea cubeba for isolation and cultivation,and the endophytic bacteria were identified by their 16S rDNA partial sequences.Redundant isolates were fused in a certain tissues through partial 16S rRNA gene sequences and colony morphology,then 16S rDNA sequences of these strains were clustered by Clustalx,phylogenetic tree was constructed by using Neighbor-Joining method,Jaccard index and biodiversity index were calculated respectively.【Result】 52 non-redundant endophytic bacterial isolates were ascertained,of which,23 isolates were from roots,8 from stems,7 from leaves and 14 from fruits.52 strains belonged to 16 species of the 7 genera containing Bacillus,Paenibacillus,Paenochrobactrum,Providencia,Pseudomonas,Sphingomonas,Lysinibacillus.40 strains belonged to Bacillus,and 16S rDNA partial sequences of 36 strains were nearest to Bacillus tequilensis,Bacillus amyloliquefaciens,Bacillus thuringiensis respectively,which accounted for 69.2% of all isolates;more strains and more species were isolated from roots and fruits,and the diversity were higher than stems and leaves;the Jaccard index of leaves and fruits was 0.56,much lower than others.【Conclusion】 The results showed that the distribution of cultivable endophytic bacteria in Litsea cubeba was allied to species of bacteria,and similar to some extent among different organs.