干旱胁迫下2个扁蓿豆品种根际细菌多样性及土壤灭菌对其生长的影响  

Rhizosphere bacterial diversity and the effects of soil sterilization on the growth of two varieties of Medicago ruthenica under drought stress

作　　者：邢静 范文强 王佳妮 石凤翎 XING Jing;FAN Wen-qiang;WANG Jia-ni;SHI Feng-ling(College of Grassland Resources and Environment,Inner Mongolia Agricultural University,Hohhot 010011,China)

机构地区：[1]内蒙古农业大学草原与资源环境学院,内蒙古呼和浩特010011

出　　处：《草业学报》2024年第12期147-159,共13页Acta Prataculturae Sinica

基　　金：内蒙古自治区科技重大专项(2021ZD0031);内蒙古种业科技创新“公开赛”重大示范项目(2022JBGS0016)资助。

摘　　要：干旱作为一种严重影响植物生长发育和作物生产的环境因素之一,需要一种高效但不会对环境造成影响的方法来缓解其对植物带来的危害。通常土壤微生物被认为可以与植物进行互作从而改善环境带来的不良影响,但仍需验证在植物受到干旱胁迫时土壤微生物是否可以发挥关键性作用?通过对蒙农2号、蒙农1号扁蓿豆进行灭菌和未灭菌处理,测定其生长表型与生理特性的变化,以揭示土壤微生物在扁蓿豆应对胁迫时所发挥的作用,同时对正常浇水及干旱胁迫后的根际土壤进行16S rRNA高通量测序分析,以期明晰品种介导的扁蓿豆根际微生物对干旱胁迫的响应变化规律,并探究发挥关键作用的菌群。结果表明,干旱胁迫下未灭菌处理显著提高了蒙农2号和蒙农1号扁蓿豆的株高增量、地上干重、地下干重,同时显著降低了脯氨酸(Pro)与丙二醛(MDA)含量,增强了过氧化氢酶(CAT)活性。正常浇水条件下,蒙农2号与蒙农1号扁蓿豆其根际细菌中变形菌门占比分别为72.83%、67.65%,根瘤菌占比分别为5.28%、3.65%;干旱胁迫后蒙农2号与蒙农1号扁蓿豆根际细菌中变形菌门相对丰度下降了8.42%、4.76%,而根瘤菌相对丰度增加了1.69%和2.35%。同时推测根瘤菌为扁蓿豆抗旱相关的核心微生物,并且蒙农2号扁蓿豆在水分充足的情况下根际富集了比蒙农1号更多的根瘤菌,这使得其在受到干旱胁迫时能够更加快速地做出反应。总而言之,研究证明土壤微生物在植物抵抗干旱胁迫中发挥了积极作用,根际微生物可以提高扁蓿豆对干旱胁迫的耐受能力,微生物组成和丰度受干旱胁迫和植物宿主的调节,且各自效果差异较大,进一步说明微生物的富集过程与植物基因型密切相关。Drought,as one of the environmental factors that severely affects plant development and crop production,requires an efficient but environmentally neutral approach to mitigate its harmful effects on plants.Soil microorganisms are known to interact with plants to ameliorate the adverse effects of environmental factors,but there is still a need to verify whether soil microorganisms play a critical role in protecting plants under drought stress.In this study,to reveal the roles of soil microorganisms in the response of Medicago ruthenica to drought stress,we compared the growth phenotypes and physiological characteristics of two cultivars of M.ruthenica(Mengnong No.2 and Mengnong No.1)growing in sterilized and unsterilized soil under drought stress.In addition,we performed high-throughput sequencing analyses of 16S rRNA extracted from the rhizosphere soils of plants under drought stress or well-watered conditions to detect differences in microbial communities in the rhizosphere of M.ruthenica under drought stress,and to determine which bacterial taxa play a key role in the drought response.The results show that,compared with plants of Mengnong No.1 and Mengnong No.2 growing in sterilized soil,those growing in unsterilized soil showed higher values for plant height,dry weight of aboveground and belowground parts,and catalase activity,and lower values for proline and malondialdehyde contents.Meanhile,in the rhizosphere soils of well-watered plants of Mengnong No.2 and Mengnong No.1,Proteobacteria accounted for 72.83%and 67.65%of rhizosphere bacteria,respectively,and Rhizobium accounted for 5.28%and 3.65%,respectively.In Mengnong No.2 and Mengnong No.1 under drought stress,the relative abundance of Proteobacteria in the rhizosphere bacterial community was decreased by 8.42%and 4.76%,respectively,and the relative abundance of Rhizobium was increased by 1.69%and 2.35%,respectively.On the basis of these results,we identified Rhizobium as the core taxon related to drought resistance in M.ruthenica.Under well-watered conditi

关 键 词：扁蓿豆 干旱胁迫 根际细菌 植物-微生物相互作用 16S rRNA测序 

分 类 号：S541.9[农业科学—作物学]