植物根圈微生物群落与功能特异性机制研究

Plant-specificity of Microbial Community and Function in Rhizosphere Soil

植物-土壤微生物交互作用在土壤养分循环、碳固存和温室气体排放等生态过程中发挥着重要作用,而植物源有机物输入被认为是植物-微生物交互作用的纽带。根圈土壤微生物在群落结构和功能上与根圈外土壤差异显著,并存在一定的植物群落特异性。植物源有机物的高度可利用性对土壤微生物具有复杂的影响,改变着土壤生态过程。因此,揭示植物源有机物的输入对土壤微生物的影响有助于深化对植物-土壤微生物反馈作用的认识,同时为养分循环调控、肥料施用时效、作物增产和温室气体排放及生态平衡维持提供理论支持。基于国内外最新相关研究进展,综述了两大类植物源有机物(根际沉积和凋落物)的组成和输入时间对土壤微生物群落结构和特定功能(以氮循环为例)的影响机制;探讨了稳定性同位素示踪技术、分子探针技术和宏基因组学等研究方法在植物-土壤微生物交互作用中的综合应用;总结了植物生命周期内植物源有机物化学组成和输入时空差异对植物特异性土壤微生物群落的诱导机制。植物源有机物输入对微生物群落结构和功能具有重要影响,不但显著提高优势微生物群落生物量、改变微生物群落结构及相关功能、调控特定土壤微生物活性,并且其化学性质多样性决定了土壤微生物群落植物特异性。因此,植物源有机物输入是驱动植物根圈特异微生物群落结构演替与功能演变的重要因子。

Plant-soil microbe interactions play an important role in driving vital ecosystem processes,including nutrient cycling,carbon sequestration,and greenhouse gas emissions.Input of plant-derived organic material is considered an important link betweenplants and soil microorganisms.The microbial community in rhizosphere soil differs significantly in structure and function from thatof non-rhizosphere soil.The input of readily available plant-derived organic material has complicated impacts on the soil microbiotaand the soil ecological processes that they mediate.Revealing the effects of plant-derived organic material on soil microbiota willcontribute to a comprehensive understanding of interactive plant-soil microbe feedbacks with benefits to nutrient cycling regulations,timing effects of fertilization,crop yield increment,and greenhouse gas reduction.The paper reviews the latest achievements in thefield,and summarizes changes of the soil microbial community structure and specific functions(nitrogen cycling)in response toinputs of two types of plant-derived materials(rhizodeposit and litters)with various chemical characteristics and littering seasonality(growing and dormant seasons)over annual plant life.Functional microbial communities in relation to soil nitrogen cycling,including ammonium oxidizers(bacteria and archaea),nitrifiers,and denitrifiers,are discussed with respect to their relationships tothe inputs of plant-derived organic material.The paper also discusses applications of stable isotope tracing,molecular probing,andmetagenomic sequencing technologies for understanding plant-soil microbial interactions and latest achievements with thesestate-of-the-art technologies in the plant-soil microbial interaction studies.Possible induction mechanisms of plant-specific soilmicrobial community by inputs of plant-derived organic material in plant life cycles are summarized upon chemical characteristicsand littering seasonality of the organic materials.The inputs of plant-derived organic material has important influences on the soilmicrobial community structure and function,significantly increasing abundance of dominant microbial populations,changing soilmicrobial community structure and related functions,and regulating specific soil microbial activities.On the other hand,the chemicaldiversity of plant-derived organic material also determines plant specificity of soil microbial community in rhizosphere.The input ofplant-derived organic material is,therefore,a driving factor for successions of plant-specific soil microbial community structure andchanges of their functions in rhizosphere.