典型农田土壤中丛枝菌根真菌-根际细菌互作及与氮磷利用的关系

Effect of interaction between arbuscular mycorrhizal fungi and rhizosphere bacteria in farmland soils on nutrients utilization

在农业生态系统中,土壤微生物是土壤-作物系统养分循环的重要驱动力,其中丛枝菌根真菌(Arbuscularmycorrhizalfungi,AMF)能够促进作物对养分的吸收,适应逆境胁迫。【目的】进一步揭示AMF和根际细菌群落的跨界网络互作,挖掘与作物氮磷利用显著相关的关键微生物类群,揭示关键类群的生态网络特征。【方法】利用Illumina测序技术对3种典型农田旱地土壤(黑土、潮土和红壤)中AMF和根际细菌群落结构进行分析;构建互作网络并利用偏冗余分析、相关性分析探究了与氮磷利用相关的潜在关键类群。【结果】3种土壤中AMF与根际细菌均以正相互作用为主。不同土壤中AMF与根际细菌互作关系差异明显,在红壤中跨界互作最为密切,其中球囊霉属真菌(Glomus)与根际细菌中的放线菌(Actinobacteria)和变形菌(Proteobacteria)之间的交互作用最多。而在黑土中主要体现为根际细菌的界内互作。与氮磷利用率显著相关的关键微生物类群主要属于球囊霉属真菌、放线菌和α变形菌。【结论】典型旱地土壤中AMF与根际细菌的正相互关系对作物氮磷利用有潜在促进作用,关键类群在有机质和养分贫乏的红壤中可能起到更重要的作用。

Soil microbes are important drivers of nutrient cycling in soil-crop system.Arbuscular mycorrhizalfungal(AMF)communities are reported to promote plant nitrogen and phosphorus utilization,especially under adversity stress.[Objective]The aim of this study is to explore the cross-kingdom microbial network between AMF and rhizosphere bacterial communities,and disentangle the potential keystones related to nutrient utilization.[Methods]Illumina sequencing and CoNet were used to construct the microbial network,and partial redundancy analysis and correlation analysis was used to explore potential keystones.[Results]Positive associations were dominant between AMF and rhizosphere bacteria in the three soil types.The interactions between AMF and bacterial communities varied in the three soils types.Cross-kingdom interactions were highest in Acrisol,mainly between Glomus and Actinobacteria and Proteobacteria.And in Phaeozem the interactions were mainly intra-kingdom interactions among rhizosphere bacteria.The microbial taxa that significantly correlated with nutrient utilization were species from Glomus,Actinobacteria and Alphaproteobacteria.[Conclusion]The positive interrelationship between AMF and rhizosphere bacteria in typical dryland soil has a potential promotion effect on the utilization of nitrogen and phosphorus.The role of keystones in Acrisol with relatively low organic matters and nutrient may be more important.