淹水时间对水稻土中地杆菌科群落结构及丰度的影响  

Effect of flooding time on community structure and abundance of Geobacteraceae in paddy soil

作　　者：由焦化[1] 夏淑红[1] 王保莉[1] 曲东[2] 

机构地区：[1]西北农林科技大学生命科学学院,杨凌712100 [2]西北农林科技大学资源环境学院,杨凌712100

出　　处：《微生物学报》2011年第6期796-804,共9页Acta Microbiologica Sinica

基　　金：国家自然科学基金(40971158)~~

摘　　要：【目的】通过模拟水稻土淹水过程,探讨地杆菌科(Geobacteraceae)群落结构和相对丰度随淹水时间的动态变化特征,揭示其群落结构和相对丰度变化与微生物Fe(Ⅲ)还原的内在联系。【方法】提取水稻土淹水培养1 h、1 d、5 d、10 d、20 d和30 d后的微生物总DNA,构建地杆菌科16S rDNA克隆文库,采用PCR-RFLP方法分析地杆菌科的群落结构和多样性变化特征,通过Real-time PCR技术测定地杆菌科相对丰度的动态变化。采用厌氧泥浆培养方法,测定水稻土中Fe(Ⅱ)产生量变化。【结果】供试水稻土中,微生物Fe(Ⅲ)还原过程在淹水培养初期变化明显,培养20 d后达到稳定期,最大铁还原潜势为10.16 mg/g,最大反应速率为1.064 mg/(g.d),最大反应速率对应的时间为4.84 d。α多样性指数显示,水稻土中地杆菌科的多样性随淹水时间延长呈现波动性变化,淹水5 d和20 d处理出现2个峰值,而淹水10 d和30 d处理的多样性明显减小。β多样性指数表明淹水过程中群落结构存在明显差异。不同淹水时间共产生了10种地杆菌科优势类型,分别属于Clade 1和Clade 2。Real-time PCR结果表明,地杆菌科与总细菌16S rDNA丰度的比值在淹水培养1 d时最小(1.20%),而20 d时达到最大值(4.54%)。【结论】淹水培养的水稻土中,地杆菌科微生物的多样性和相对丰度的动态变化与微生物Fe(Ⅲ)还原过程密切相关。[Objective] The dynamic characteristics of community structure and relative abundance of Geobacteraceae were investigated to understand their response to microbial iron（Ⅲ） reducing in flooded paddy soil.[Methods] The paddy soil was incubated anaerobically and the amount of Fe（II） was determined during the flooding incubation.We retrieved Geobacteraceae sequences from clone libraries constructed for different time points（1 h and day 1,5,10,20 and 30） after flooding of the paddy soil.The diversity and community structure were analyzed by using RFLP method,and the relative abundance of Geobacteraceae was detected by real-time PCR.[Results] Microbial reduction of iron（Ⅲ） changed greatly in early time and was stable after incubated for 20 d in paddy soil.The largest iron reduction potential was 10.16 mg/g with a Vmax of 1.064 mg/（g.d） at the time of 4.84 d whereas this process achieved plateau after 20 days flooding.Diversity of Geobacteraceae,given by alpha indices,fluctuated during the flooding incubation.Two peaks of diversity were observed in treatments of 5 d and 20 d respectively,while significant low diversity appeared in samples of 10 d and 30 d.Beta indices described the differences between community structures of Geobacteraceae and hence reflected the variation of the flooding situation over time.In all samples,10 RFLP-based preponderant types were found,which fell into clade 1 and clade 2 of Geobacteraceae.The relative abundance of Geobacteraceae was the lowest in 1 d（1.20%） and the highest in 20 d（4.54%）.[Conclusion] The dynamic variation of Geobacteraceae diversity,community structure and abundance are closely related to microbial iron（Ⅲ） reducing in flooding paddy soil.

关 键 词：水稻土 地杆菌科 群落结构 丰度 RFLP 

分 类 号：S154.3[农业科学—土壤学]