Soil salinization, regarded as a “hidden killer of agriculture”, is a globally agricultural problem threatening crop growth and productivity. Chinese farmlands, responsible for feeding 1.4 billion people, have to provide agriculture products as much as possible via applying fertilizers. Consequently, the excessive application of inorganic fertilizer leads to soil salinization, and low precipitation and poor agricultural management intensifies salinization. Therefore, it is necessary to evaluate tillage potential of salinized agricultural soils via estimating soil ecosystem multifunctionality regarded asan important index for assessing soil nutrient turnover and retention as well as flora diversity. However, relationships between soilecosystem multifunctionality and rare and abundant bacterial diversity are poorly understood.   

Associate professor WAN Wenjie of the Environmental Genomics Group inWuhan Botanical Garden, collaborated with professorCHENWenli andprofessor HUANGQiaoyunof theHuazhong Agricultural University.   

The researchersselected a salinized area in Yingcheng City (Hubei Province, China) as the research object, anddetermined community composition and diversity of soil bacteria and measured soil physicochemical properties and enzymatic activities. Furthermore, theresearchers employedmultiple statistical analysis approaches to calculate ecosystem multifunctionality, community functional redundancy, environmental breadths, phylogenetic signals, phylogenetic clustering, and community assembly processes.   

Abundant bacteria possess higher functional redundancies and stronger phylogenetic signals for environmental preferences than rare bacteria, while rare bacteria present closer phylogenetic clustering and broader response thresholds to almost all environmental varibales than abundant ones.    

Variable selectioncontributes most to rare bacterial community assembly,whiledispersal limitation and variable selectioncontributes largely to abundant bacterial community assembly. Salinityis the crucial factor adjusting thebalance between stochastic and deterministic processesof both rare and abundant bacteria subcommunities in salinized agricultural soils.  

Taxonomica-diversity of rare bacteria and phylogenetica-diversity of abundant bacteria show significant effects onecosystem multifunctionality in salinized agricultural soils. Meanwhile, taxonomica-diversity of abundant bacteria and phylogenetica-diversity of rare bacteria have little influence on soilecosystem multifunctionality. Besides, abundant bacterial community functions contribute significantly to soil ecosystem multifunctionality, while rare bacterial do not.    

Deciphering the diversity of rare and abundant bacteria and their contributions to ecosystem multifunctionality in salinized soils is critical for guiding soil restoration. 

The research was funded by the National Natural Science Foundation of China,National Key Research and Development Program of China, and Technical Innovation Major Projects of Hubei Province.  

The findings of this research have been published in the SCI Journal ofmSystems, with the title of “Bridging Rare and Abundant Bacteria with Ecosystem Multifunctionality in Salinized Agricultural Soils: from Community Diversity to Environmental Adaptation”.   

Associate professor WAN Wenjie is the first author of this paper, professorCHENWenli and HUANG Qiaoyunare the corresponding authors, and theKey Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden of the Chinese Academy of Sciences is thethird institute. 

   

Abundant bacteria possess higher functional redundancies and stronger phylogenetic signals of ecological preferences than rare ones, while rare bacteria show closer phylogenetic clustering and broader environmental breadths than abundant ones. Soil salinity is the crucial factor in determining community assembly of rare and abundant bacteria, showing distinct changes in stochasticity with higher salinity (Image by WAN Wenjie)