A highly conserved core bacterial microbiota with nitrogen-fixation capacity inhabits the xylem sap in maize plants

作者：Liyu Zhang, Meiling Zhang, Shuyu Huang, Lu‐Jun Li, Qiang Gao, Yin Wang, Shuiqing Zhang, Shaomin Huang, Liang Yuan, Yanchen Wen, Kailou Liu, Xichu Yu, Dongchu Li, Lu Zhang, Xinpeng Xu, Hai‐Lei Wei, Ping He, Wei Zhou, Laurent Philippot, Chao Ai · 发表于：Nature Communications · 年份：2022 · DOI：10.1038/s41467-022-31113-w · 被引用次数：248 · 研究领域：Legume Nitrogen Fixing Symbiosis、Plant-Microbe Interactions and Immunity、Microbial Community Ecology and Physiology

Abstract Microbiomes are important for crop performance. However, a deeper knowledge of crop-associated microbial communities is needed to harness beneficial host-microbe interactions. Here, by assessing the assembly and functions of maize microbiomes across soil types, climate zones, and genotypes, we found that the stem xylem selectively recruits highly conserved microbes dominated by Gammaproteobacteria. We showed that the proportion of bacterial taxa carrying the nitrogenase gene ( nifH ) was larger in stem xylem than in other organs such as root and leaf endosphere. Of the 25 core bacterial taxa identified in xylem sap, several isolated strains were confirmed to be active nitrogen-fixers or to assist with biological nitrogen fixation. On this basis, we established synthetic communities (SynComs) consisting of two core diazotrophs and two helpers. GFP-tagged strains and 15 N isotopic dilution method demonstrated that these SynComs do thrive and contribute, through biological nitrogen fixation, 11.8% of the total N accumulated in maize stems. These core taxa in xylem sap represent an untapped resource that can be exploited to increase crop productivity.