水葫芦内生细菌脂肪酸生物标记特性研究（Characteristics of PLFA Biomarkers for the Endophyte Bacteria inside Eichhornia crassipe（Mart.）Solms）

应用基于微生物细胞脂肪酸成分鉴定的全自动微生物鉴定系统,鉴定水葫芦内生细菌25株,分属15个属.共检测到27个脂肪酸生物标记(PLFAs),这些生物标记分为4种类型,即(1)高频次分布:在25株细菌中出现13～22次,属于细菌总体类群(general)的生物标记.(2)中频次分布:在25株细菌中出现5～7次,可以用于代表细菌属类群(genus)识别生物标记.(3)低频次分布:在细菌中的分布概率较小,可以用于指示特定细菌种间差异的生物标记.(4)微频次分布:仅在一种细菌种类出现,是细菌种(species)特征生物标记.利用脂肪酸生物标记分析同属细菌不同种的差异,可将微杆菌属分为2类,第1类包括菌株9Microbacterium barkeri和11Microbacterium imperiale,这两个菌株17:0ISO和14:0ISO的脂肪酸生物标记含量均为0.第2类包括10Microbacterium esteraromaticum、12Microbacterium lacticum和13Microbacterium liquefaciens,这3个菌株均含有17:0ISO脂肪酸生物标记而区别于第一类菌株.利用脂肪酸生物标记的差异对25株内生细菌进行聚类分析,可将水葫芦内生细菌类群分为4类.不同植物内生菌群落中存在着特异的生物标记,利用特征脂肪酸生物标记的分析方法,分析水葫芦内生细菌的群体特性,对于植物内生菌微生物群落的研究具有重要意义.

Characteristics of PLFA Biomarkers for the Endophyte Bacteria inside Eichhornia crassipe(Mart.)Solms

The present paper dealt with isolation and identification of the endophyte bacteria from Eichhornia crassipe(Mart.)Solms.as well as characteristics of their PLFA biomarkers.Results showed that 25 species of endophyte bacteria were identified by means of microbe identification system(MIDI system from USA).There were 27 PLFA biomarkers detected in 25 species of endophyte bacteria,in which based on the distribution frequency in the bacteria 4 types were clustered e.g.(1)high frequency related to characteristics of microbe in general,(2)middle frequency related to bacteria in general,(3)low frequency related bacterial genus,(4)tiny frequency related to species.According to PLFAs biomarkers,5species of genus Microbacterium were divided into 2 groups,the groups 1 included Microbacterium barkeri and Microbacterium imperiale,there were no biomarker of 17:0 ISO and 14:0 ISO.The groups 2 included Microbacterium esteraromaticum,Microbacterium lacticum and Microbacterium liquefaciens with 17:0 ISO biomarker higher than 1.85% .Using the cluster analysis method the 25 species were classified into 4 groups based on the PLFAs biomarkers.The characteristics of the groups were discussed.There were the specific biomarker represented the endiophyte bacterica which also isolated from other plants.The research provided the analysis pattern to treat the PLFA biomarkers and analyse group characteristics of endophyte bacteria to clear the community structure of endophyte bacteria in Eichhornia crassipe(Mart.) Solms.