不同绿肥对湘西烟田土壤细菌群落结构与多样性的影响

Effects of Different Green Manure on Bacterial Community Structure and Diversity in Tobacco-planting Field in Xiangxi

为了解施用不同绿肥烟田土壤细菌群落的物种多样性,从湖南省湘西州烟区采集4块烟田（不施绿肥,单施黑麦草绿肥,豌豆绿肥,油菜绿肥）的土壤样本,提取土壤总DNA,PCR扩增其16SrRNA的V4高变区,阳性样品测序,序列比对鉴定,并利用生物信息学软件分析测序数据。结果表明：1）施用绿肥对土壤细菌群落结构和组成具有显著影响。在细菌域有4个主要的细菌种群,占所有有效序列的55.79%~65.39%,分别为变形菌门（Proteobacteria）、酸杆菌门（Acidobacteria）、放线菌门（Actinobacteria）和绿弯菌门（Chloroflexi）,4个细菌种群相对丰度在各组均具有显著差异。2）经绿肥处理后的烟田土壤细菌群落多样性高于未施用绿肥的对照组。香农多样性指数和群落均一度指数对照组（6.637,0.833）和油菜组（6.658,0.833）均低于黑麦草组（6.923,0.854）和豌豆组（6.992,0.861）,且差异均达显著水平。3）施用绿肥尤其是黑麦草绿肥的烟田中,烟草青枯病的发病率下降与土壤细菌群落多样性增加有关。

In order to explore the species diversity of bacterial community in tobacco-planting field applied with different green manure,soil samples were collected in four tobacco-planting fields in Xiangxi,Hunan Province,which were treated with different green manure（control,ryegrass,pea and rape）,after extracting total DNA from soil,PCR amplification of V4 hypervariable region of 16 SrRNA,positive sample sequencing and alignment,and then sequence data were analyzed by using bioinformatics software.Results：Applying green manure had positive influence on soil bacteria community structure and composition.Within the bacterial domain,four major bacterial phyla accounted for 55.79%to 65.39% of all reads,and they were Proteobacteria,Acidobacteria,Actinobacteria and Chloroflexi.Soil community diversity was significantly higher in groups treated with green manure.Shannon diversity index and Pielou evenness index were significantly（P〈0.05）lower in Control（6.637,0.833）and Rape（6.658,0.833）,but higher in Ryegrass（6.923,0.854）and Pea（6.992,0.861）.Green manure especially ryegrass,decreased tobacco disease（bacterial wilt）rate dramatically,which correlated with the increasing of soil bacteria community diversity.