稻虾共作对稻田水体微生物多样性和群落结构的影响

Effects of rice-crayfish integrated system on microbial diversity and community structure in paddy water

为探究稻虾共作对稻田水体微生物多样性和群落结构的影响,基于16S rDNA扩增子高通量测序,结合生物信息分析,比较稻虾共作模式(RC)和水稻单作模式(RM)中水体微生物的多样性和群落结构。结果显示,RC中水体微生物的多样性极显著高于RM。水体微生物的群落结构在2种模式中差异显著,且水体理化性质,如总氮、亚硝酸盐氮等的含量与2种模式中水体微生物群落结构的差异显著关联。相比于RM,RC水体中放线菌门(Actinobacteria)和蓝细菌门(Cyanobacteria)的相对丰度更高,而变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)的相对丰度更低。放线菌目(Actinomycetales)、根瘤菌目(Rhizobiales)、聚球藻目(Synechococcales)等为RC主要的水体微生物标志物,而黄杆菌目(Flavobacteriales)、β-变形菌目(Betaproteobacteriales)、红环菌目(Rhodocyclales)等则为CM主要的水体微生物标志物。在稻田水体微生物群落中鉴定出6个基石种,主要属于伯克氏菌科(Burkholderiaceae)、腐螺旋菌科(Saprospiraceae)和多囊菌科(Polyangiaceae)等。通过功能预测及其相对丰度比较,发现RC中水体微生物的代谢通路的相对丰度高于RM,尤其是能量代谢通路的相对丰度极显著地高于RM。以上研究表明,相比于水稻单作,稻虾共作显著提高了稻田水体微生物的多样性,塑造了组成更健康、功能更强大的水体微生物群落,提高了稻田生态系统的物质循环能力和能量利用效率,有利于稻田水体净化,并维持稻田生态系统稳定。

Rice-crayfish integrated system(RC)is a high-efficiency ecological agricultural system which combines the rice planting and crayfish culturing.In order to explore the impact of RC on the microbiome of paddy water,the water microbial diversity and community structure of RC and rice monoculture system(RM)were determined by using 16S rDNA amplicon high-throughput sequencing.The results showed that RC significantly improved the microbial diversity.The microbial community structure of paddy water was significantly different between RC and RM,which could be attributed to water physi-chemical factors,such as total nitrogen and nitrite nitrogen.The relative abundance of Actinobacteria and Cyanobacteria in RC was significantly higher than that in RM,while the relative abundance of Proteobacteria and Bacteroidetes in RC was lower than that in RM.Actinomycetales,Rhizobiales,and Synechococcales are the main biomarkers of water microbiome in RC,while Flavobacteriales,Betaproteobacteriales,and Rhodocyclales are the main biomarkers in RM.Six keystone taxa were identified from the water microbiome in the paddy fields,which mainly belong to Burkholderiaceae,Saprospiraceae and Polyangiaceae.Furthermore,through functional prediction and relative abundance comparison,we found that the metabolic capacity of water microbiome in RC was significantly higher than that in RM,especially the relative abundance of energy metabolism pathway was significantly higher than that in RM.In conclusion,RC formed a better water microbiome with high diversity,stable structure,and strong function and improved the material circulation and energy utilization rate of paddy ecosystem.Those results provide a basis for the utilization of microbial resource in rice-crayfish integrated system.