酸性红壤上玉米不同部位固氮微生物群落丰度和组成特征  

Diazotroph abundance and community composition in different parts of maize(Zea mays L.)cultivated in acid red soil

作　　者：王超[1,2] 陈娟 沈仁芳[1,2] WANG Chao;CHEN Juan;SHEN Ren-fang(State Key Laboratory of Soil and Sustainable Agriculture/Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education/Hohai University,Nanjing 210098,China)

机构地区：[1]土壤与农业可持续发展国家重点实验室/中国科学院南京土壤研究所,南京210008 [2]中国科学院大学,北京100049 [3]浅水湖泊综合治理与资源开发教育部重点实验室/河海大学,南京210098

出　　处：《植物营养与肥料学报》2021年第5期741-750,共10页Journal of Plant Nutrition and Fertilizers

基　　金：国家重点研发计划(2018YFC0407604);国家自然科学基金项目(42020104004)。

摘　　要：【目的】发挥微生物固氮功能可降低农田化学氮肥的投入,对于缓解土壤酸化具有重要意义。固氮微生物广泛存在于植物体的各个部位,了解酸性土壤上作物不同部位固氮微生物群落特征,为挖掘其功能潜力提供数据支撑和理论基础。【方法】选择性状差异较大的耐铝玉米品种先玉335和铝敏感品种Mo17为试验材料,在酸性红壤上种植1个月后,收集玉米地上部、根部和根际土壤样品,分析玉米生物量、养分含量和根际土壤基本理化性质;采用实时荧光定量PCR和高通量测序技术,以nifH基因为标靶,分析不同玉米品种、不同取样部位(叶部、根部和根际土壤)固氮微生物群落的丰度、多样性和结构组成。【结果】先玉335地上和地下生物量显著高于Mo17,但是植株氮、磷浓度和根际土壤pH、铵态氮和速效钾含量却低于Mo17。实时荧光定量PCR结果显示,nifH基因丰度在玉米不同部位间的差异程度明显大于玉米品种间的差异,其中根部丰度显著高于根际土壤和叶部,而且先玉335根部nifH基因丰度要高于Mo17。高通量测序分析显示,变形菌门(Proteobacteria)和蓝藻门(Cyanobacteria)是固氮微生物的优势门,根际土壤和根部的优势菌属是慢生根瘤菌属(Bradyrhizobium),而叶部优势菌属是细鞘丝藻属(Leptolyngbya),多数优势菌属相对丰度在玉米不同部位间呈现显著差异。取样部位显著影响固氮微生物群落多样性指数(Shannon指数和OTU数量),但同一部位品种间没有明显差异,其中根际多样性指数显著高于根部,两者均高于叶部。非度量多维尺度(NMDS)和PERMANOVA分析显示,取样部位对固氮微生物群落结构组成的影响程度显著高于品种的影响,根际土壤、根部和叶部三者之间的群落组成差异达到显著水平,而品种间仅仅根际土壤样品差异显著。【结论】酸性红壤上,玉米不同部位间的固氮微生物群落丰度、多样性和�【Objectives】Biological nitrogen fixation(BNF)plays an important role in reducing the input of chemical N fertilizer,which is of great significance to alleviate soil acidification.N-fixing microorganism(diazotroph)widely exists in all sites of plants.Understanding of the abundance,diversity and composition of diazotrophic communities in different parts of maize will provide data support and theoretical basis for the potentials of BNF.【Methods】Two maize cultivars with different Al-tolerance levels,Xianyu 335(relatively Al-tolerant cultivar)and Mo17(Al-sensitive cultivar),were grown in an acidic soil.After 30 days,maize shoot,root,and biomass data were collected.At the same time,nutrient content in the plants and rhizosphere soils as well as the physicochemical properties of rhizosphere soils were determined.Based on nifH gene,diazotroph abundance was determined by quantitative RT-PCR and community composition was assayed using high-throughput sequencing.【Results】Compared with Mo17,Xianyu 335 had higher biomass of shoot and roots,but lower plant N and P concentration,rhizosphere soil pH,NH_(4)^(+)-N and readily available K contents.The results of quantitative RT-PCR showed that the difference of nifH gene abundance among different parts of maize was greater than that between maize cultivars.The nifH gene abundance in roots was significantly higher than those in rhizosphere soils and leaves,and the abundance in the roots of Xianyu 335 was higher than that in Mo17.High throughput sequencing analysis showed that Proteobacteria and Cyanobacteria were the dominant phyla,Bradyrhizobium was the dominant genus in both rhizosphere and root samples,and Leptolyngbya was the dominant genus in leaves.The relative abundance of most of the dominant genera showed significant differences among different parts of maize.Sampling sites significantly affected the diversity index of diazotrophic community(Shannon index and OTU number),but there was no significant difference among cultivars in the same site.The diversity index

关 键 词：酸性土壤 固氮微生物 微生物群落结构 玉米 植物耐铝性 

分 类 号：S154.3[农业科学—土壤学] S513[农业科学—农业基础科学]