Effect of Different Bacterial-Feeding Nematode Species on Soil Bacterial Numbers,Activity,and Community Composition  

作　　者：XIAO Hai-Feng LI Gen LI Da-Ming HU Feng LI Hui-Xin 

机构地区：[1]Key Laboratory of Tropical Forest Ecology,Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences [2]College of Resources and Environmental Sciences,Nanjing Agricultural University

出　　处：《Pedosphere》2014年第1期116-124,共9页土壤圈（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Nos.41271270 and 31200409)

摘　　要：The effects of bacterial-feeding nematodes on bacterial number, activity, and community composition were studied through a microcosm experiment using sterilized soil inoculated with soil bacteria （soil suspension） and with bacteria and three species of bacterial-feeding nematodes （ Cephalobus persegnis, Protorhabditis filiformis, and Caenorhabditis elegans）. Catalyzed reporter deposition-fluorescence in situ hybridization, CO2 evolution, and denaturing gradient gel electrophoresis （DGGE） of PCR ampli- fied 16S rRNA gene fragments were used to investigate bacterial numbers, antivity, and community composition, respectively. Our results showed that bacterial numbers and activity significantly increased in the presence of bacterial-feeding nematodes, which indicated that bacterial-feeding nematodes had a significant positive effect on soil bacteria. The different nematode species had different effects on bacterial numbers and activity. C. persegnis and P. filiformis, isolated from native soil, increased the bacterial number and activity more than C. elegans. The DGGE analysis results showed that dominant bacterial species significantly differed among the treatments, which suggested that bacterial-feeding nematode species modified the bacterial community composition in soil. Further gene sequence analysis results showed that the dominant bacterial species in this study were gram-negative bacteria. Given the completely same conditions except nematode species, the varied selective feeding behavior of different nematode species was the most likely reason for the altered bacterial community composition. Overall, the alteration of bacterial numbers, activity and community composition resulting from the bacterial-feeding nematodes may ult!mately affect soil ecological functioning and processes.The effects of bacterial-feeding nematodes on bacterial number,activity,and community composition were studied through a microcosm experiment using sterilized soil inoculated with soil bacteria(soil suspension)and with bacteria and three species of bacterial-feeding nematodes(Cephalobus persegnis,Protorhabditis filiformis,and Caenorhabditis elegans).Catalyzed reporter deposition-fluorescence in situ hybridization,CO_2 evolution,and denaturing gradient gel electrophoresis(DGGE)of PCR.amplified 16S rRNA gene fragments were used to investigate bacterial numbers,activity,and community composition,respectively.Our results showed that bacterial numbers and activity significantly increased in the presence of bacterial-feeding nematodes,which indicated that bacterial-feeding nematodes had a significant positive effect on soil bacteria.The different nematode species had different effects on bacterial numbers and activity.C.persegnis and P.filiformis,isolated from native soil,increased the bacterial number and activity more than C.elegans.The DGGE analysis results showed that dominant bacterial species significantly differed among the treatments,which suggested that bacterial-feeding nematode species modified the bacterial community composition in soil.Further gene sequence analysis results showed that the dominant bacterial species in this study were gram-negative bacteria.Given the completely same conditions except nematode species,the varied selective feeding behavior of different nematode species was the most likely reason for the altered bacterial community composition.Overall,the alteration of bacterial numbers,activity and community composition resulting from the bacterial-feeding nematodes may ultimately affect soil ecological functioning and processes.

关 键 词：CARD-FISH CO2 evolution DGGE gene sequence gram-negative bacteria 

分 类 号：S154.3[农业科学—土壤学]