摘要:稻虾共作是水稻种植与克氏螯虾共作形成的互利共生的稻田种养复合生态模式。目前对稻虾共作模式稻田反硝化微生物多样性和群落结构的影响尚不清楚。本研究以江汉平原常规中稻模式（MR）为对照，设置连续3年（2014-2016年）稻虾共作模式（CR）为处理，通过特异引物提取中稻抽穗期稻田土壤nirK基因，采用Illumina Miseq高通量测序技术，探讨稻虾共作模式对稻田土壤nirK反硝化微生物多样性和群落结构的影响。结果表明：稻虾共作模式显著提升水稻抽穗期稻田土壤中硝态氮、全氮及全碳的含量，对土壤碳氮比、碱解氮和铵态氮含量没有显著影响。稻虾共作模式显著增加稻田土壤nirK基因微生物的丰富度指数，但对nirK基因微生物的多样性指数影响不显著。稻虾共作模式改变了nirK基因微生物在目、科、属、种水平的群落组成，较常规中稻模式，稻虾共作模式在各分类水平组成类群均减少；稻虾共作模式较常规中稻模式改变了目的种类，对共有目相对丰度没有显著性改变。RDA分析表明稻虾共作模式对土壤nirK基因菌群的群落结构有一定的改变，但稻虾共作模式与常规中稻模式在群落结构上仍保留着一定的相似性。硝态氮含量是影响nirK反硝化细菌群落结构的主效因子。可见，稻虾共作模式对微生物多样性指数没有显著影响，但显著增加了微生物丰富度指数，改变了稻田土壤nirK反硝化微生物在目、科、属、种的群落结构。
关键词:江汉平原/
稻虾共作/
克氏螯虾/
nirK基因/
反硝化微生物/
群落结构/
硝态氮/
高通量测序技术
Abstract:Integrated rice-crayfish farming system is a symbiotic ecological model applicable in paddy field cultivation that is based on the combination of rice planting and clawed crayfish breeding in waterlogged conditions. In spite of so many efforts, the effects of integrated rice-crayfish farming system on denitrifying micro-organism diversity and community structure have remained unclear. In this study, we analyzed soil samples from both consecutive treatment of integrated rice-crayfish farming system (CR) in 2014-2016 and traditional paddy field (MR) treatment in order to investigate the effects of integrated rice-crayfish farming system on microbial diversity and community structure of nirK denitrification in paddy soils.. This was done by extracting soil nirK gene from rice field at heading stage using specific primers and Illumina Miseq high-throughput sequencing technology. The results showed that CR significantly increased the contents of nitrate nitrogen, total nitrogen and total carbon in paddy soils at heading stage, but had no significant effect on the ratio of carbon to nitrogen, contents of available nitrogen and ammonium nitrogen in soil. Compared with MR, CR significantly increased nirK gene abundance in soil, but did not significantly change its diversity. CR treatment changed the composition of nirK gene micro-organisms in the levels of order, family, genus and species. Compared with MR, CR reduced all taxonomic groups. The analysis of relative abundance of order showed no significant difference between CR and MR treatments. CR treatment changed species order, but did not change the relative abundance of common orders. RDA analysis showed that CR significantly changed community structure of nirK gene in soil. Nitrate nitrogen content was the main factor affecting the community structure of nirK denitrifying bacteria. It was obvious that rice-crayfish farming system had no significant effect on microbial diversity, but significantly increased microbial abundance index. In addition, it changed nirK denitrifying microbial community structure in terms of order, family, genus and species.
Key words:Jianghan Plain/
Rice-crayfish farming system/
Clawed crayfish/
nirK gene/
Denitrification microbe/
Community structure/
Nitrate nitrogen/
High-through put sequencing technology
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