dnaE2expression promotes genetic diversity and bacterial persistence in mycobacterial biofilms

Abstract

AbstractThe complex cellular architecture and the microenvironments within the biofilm give rise to a population that is both physiologically and genetically heterogeneous. Transcriptome analysis ofMycobacterium smegmatisin biofilm culture and its transition phase into planktonic growth was performed to identify the genetic basis of heterogeneity in the biofilm. While there was an increase in the expression of mycobacterial mutasome consisting ofdnaE2, imuA, andimuBin the biofilm, the mutation burden was less compared to the planktonic culture. Deletion ofdnaE2causes lower mutation frequency and bacterial fitness in comparison to the parental strain in biofilm culture. The expression ofdnaE2contributes to a slower bacterial growth rate, potentially promoting persister formation. Our study uncovers the multiple benefits ofdnaE2expression in biofilm such as increasing genetic diversity and reducing growth rate; both of which are necessary for mycobacterial survival and adaptation.