Genetically engineered rpsL merodiploidy impacts secondary metabolism and antibiotic resistance in Streptomyces

AbstractCertain point mutations within gene for ribosomal protein S12,rpsL, are known to dramatically change physiological traits of bacteria, most prominently antibiotic resistance and production of various metabolites. TherpsL mutants are usually searched among spontaneous mutants resistant to aminoglycoside antibiotics, such as streptomycin or paromomycin. The shortcomings of traditional selection are as follows: randomrpsL mutants may carry undesired genome alterations; manyrpsL mutations cannot be isolated because they are either not associated with increased antibiotic resistance or non-viable in the absence of intactrpsLWT gene. Introduction of mutantrpsL alleles in therpsLWT background can be used to circumvent these obstacles. Here we take the latter approach and report the generation and properties of a set of stablerpsL merodiploids forStreptomyces albus J1074. We identified severalrpsL alleles that enhance endogenous and heterologous antibiotic production by this strain and show thatrpsLWTrpsLK88E merodiploid displays increased streptomycin resistance. We further tested several promisingrpsL alleles in two more strains,Streptomyces cyanogenus S136 andStreptomyces ghanaensis ATCC14672. In S136, plasmid-bornerpsLK88E+P91S andrpsLK88R led to elevated landomycin production; no changes were detected for ATCC14672 merodiploids. Our data outline the prospects for and limitations torpsL merodiploids as a tool for rapid enhancement of secondary metabolism inStreptomyces.
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research