Rhizospheres can promote self-transmissible plasmid transfer,however,the corresponding mechanism has not received much attention.Plant-microbe remediation is an effective way to promote pollutant biodegradation;however,some pollutants,such as naphthalene,are harmful to plants and result in inefficient plant-microbe remediation.In this study,trans-fer of a TOL-like plasmid,a self-transmissible plasmid loaded with genetic determinants for pollutant degradation,among different bacteria was examined in bulk and rhizosphere soils as well as addition of maize root exudate and its artificial root exudate(ARE).The results showed that the numbers of transconjugants and recipients as well as bacterial metabolic activities,such as xylE mRNA expression levels and catechol 2,3-dioxygenase(C23O)activ-ities of bacteria,remained high in rhizosphere soils,when compared with bulk soils.The number of transconjugants and bacterial metabolic activities increased with the increasing exudate and ARE concentrations,whereas the populations of donor and recipient bacteria were substantially unaltered at all concentrations.All the experiments consistently showed that a certain number of bacteria is required for self-transmissible plasmid transfer,and that the increased plasmid transfer might predominantly be owing to bacterial metabolic activ-ity stimulated by root exudates and ARE.Furthermore,ARE addition increased naphthalene degradation by transconjugants in both culture medium and soil.Thus,the combined action of a wide variety of components in ARE might contribute to the increased plasmid transfer and naphthalene degradation.These findings suggest that ARE could be an effectively al-ternative for plant-microbe remediation of pollutants in environments where plants cannot survive.

Qiuyan Jiang;Wenwei Lu;Lei Zhang;Yeqing Jin;Yujing Wang;Jun Chen;Ziyi Ye;Ming Xiao

Development Center of Plant Germplasm,College of Life Sciences,Shanghai Normal University,Shanghai 200234,China;Key Laboratory of Urban Agriculture,Ministry of Agriculture,Shanghai 200240,China;Department of Food Science,Shanghai Business School,Shanghai 200235,China;Shanghai Landscape Architecture Construction Co.,Ltd.,Shanghai 200235,China

环境科学学报（英文版）

[1]Qiuyan Jiang;Wenwei Lu;Lei Zhang;Yeqing Jin;Yujing Wang;Jun Chen;Ziyi Ye;Ming Xiao-.Promotion mechanism of self-transmissible degradative plasmid transfer in maize rhizosphere and its application in naphthalene degradation in soil)[J].环境科学学报（英文版）,2022(05):240-252

Rhizospheres,exudate,transconjugants,xylE,C23O,exudates

Promotion,mechanism,self,transmissible,degradative,plasmid,transfer,maize,rhizosphere,its,application,naphthalene,promote,however,corresponding,has,received,much,attention,Plant,microbe,remediation,way,biodegradation,some,pollutants,such,harmful,plants,inefficient,In,this,study,TOL,like,loaded,genetic,determinants,among,different,was,examined,bulk,soils,well,addition,root,artificial,ARE,results,showed,that,numbers,recipients,bacterial,metabolic,activities,expression,levels,catechol,dioxygenase,remained,high,when,compared,increased,increasing,concentrations,whereas,populations,donor,were,substantially,unaltered,All,experiments,consistently,certain,required,might,predominantly,owing,ity,stimulated,by,Furthermore,both,culture,medium,Thus,combined,action,wide,variety,components,contribute,These,findings,suggest,could,effectively,ternative,environments,cannot,survive

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