Depth-dependent effects of leguminous crops on soil nitrogen-fixing microbial communities  

豆科作物对土壤固氮微生物群落影响的土层深度依赖性

作　　者：Yi-Heng Tao Yi Fan Shuang Pang Shu-Han Zhang Jing-Kuan Wang Hong-Tao Zou Jiu-Bo Pei Xi-Mei Zhang 

机构地区：[1]College of Land and Environment,Shenyang Agricultural University,Shenyang 110161,China [2]Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081,China [3]State Key Laboratory of Efficient Utilization of Agricultural Water Resources,China Agricultural University/Chinese Academy of Agricultural Sciences,Beijing 100193/100081,China

出　　处：《Journal of Plant Ecology》2024年第6期291-306,共16页植物生态学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(U21A20188,32071547);the Top‐Notch Young Talents Program(to Ximei Zhang)of China,and the Agricultural Science and Technology Innovation Program(to Ximei Zhang).

摘　　要：Legumes play critical roles in agroecosystems by modulating nitrogen-fixing microorganisms to enhance soil fertility and promote crop productivity.Current research on the effects of legumes predominantly focuses on surface soil,lacking a comprehensive analysis of their overall impact across multiple soil layers and an in-depth understanding of associated microbial mechanisms.Here,the community structure of soil nitrogen-fixing microorganisms in three soil layers(0-20 cm,20-50 cm and 50-100 cm)under legume and non-legume cultivation was investigated through metagenomic sequencing.We found that only in topsoil(0-20 cm)legume treatment exhibited a significantly higher relative abundance of nitrogen-fixing genes than non-legume treatment.Under legume cultivation,the relative abundance of nitrogen-fixing genes was significantly higher in the topsoil layer than in deeper layers,whereas non-legume treatment displayed an inverse depth-dependent pattern.Combining soil physicochemical properties,the relative abundance of nitrogen-fixing genes correlated significantly with soil moisture,total carbon(TC),and dissolved organic carbon(DOC)content.Both TC and DOC were identified as key drivers of these genes.Subsequently,a similar depth-dependent pattern within the relative abundance of soil carbon degradation genes was found in response to the cultivation of both crops.The relative abundances of soil carbon degradation genes were negatively correlated with nitrogen-fixing genes under legume treatment individually,distinct from non-legume treatment.Our findings highlight the depth-dependent impact of legumes on nitrogen fixation and the critical interaction between soil carbon degradation and nitrogen fixation,providing insights into carbon management in legume cultivation practices to enhance nitrogen fixation in future agriculture.豆科作物能通过刺激固氮微生物提高土壤养分含量和作物生产力。然而,目前对豆科植物影响固氮微生物的研究多集中在表土,而对深层土壤的整体影响及对相关微生物的作用机制仍缺乏深入分析。本研究通过宏基因组测序技术,探究了种植豆科和非豆科作物对0-20,20-50和50-100 cm土层中土壤固氮微生物群落结构的影响。研究发现,种植豆科作物处理的固氮基因(nifH,nifD和nifK)相对丰度仅在表层土(0-20 cm)中显著高于种植非豆科作物处理。在种植豆科作物处理下,表层土固氮基因的相对丰度显著高于深层土,而种植非豆科作物处理下固氮基因的相对丰度表现出与之相反的深度依赖性模式。结合土壤理化性质,我们发现固氮基因的相对丰度与土壤水分、总碳(TC)和可溶性有机碳(DOC)含量显著相关。随机森林模型分析的结果也表明,土壤TC和DOC是影响固氮基因的关键因素。进一步分析发现,两种作物种植下不同土层的碳分解基因的相对丰度也呈现出与固氮基因类似的土层深度依赖性模式。在豆科作物种植下,土壤中碳分解基因的相对丰度与固氮基因的相对丰度呈负相关,这与非豆科作物的结果不同。这些研究结果强调了豆科植物对固氮微生物群落影响的土层深度依赖性,以及土壤碳分解与固氮过程之间的相互作用,为未来农业通过碳管理来增强豆科作物的固氮作用提供了重要启示。

关 键 词：nif gene family METAGENOMICS SUBSOIL Glycine max carbon-nitrogen interaction 

分 类 号：S15[农业科学—土壤学]