Mutations in rpsL that confer streptomycin resistance show pleiotropic effects on virulence and the production of a carbapenem antibiotic in Erwinia carotovora

Abstract

Spontaneous streptomycin-resistant derivatives of Erwinia carotovora subsp. carotovora strain ATTn10 were isolated. Sequencing of the rpsL locus (encoding the ribosomal protein S12) showed that each mutant was missense, with a single base change, resulting in the substitution of the wild-type lysine by arginine, threonine or asparagine at codon 43. Phenotypic analyses showed that the rpsL mutants could be segregated into two groups: K43R mutants showed reduced production of the b-lactam secondary metabolite 1-carbapen-2-em-3 carboxylic acid (Car), but little effect on exoenzyme production or virulence in potato tuber tests. By contrast, the K43N and K43T mutations were pleiotropic, resulting in reduced exoenzyme production and virulence, as well as diminished Car production. The effect on Car production was due to reduced transcription of the quorum-sensing-dependent car biosynthetic genes. The effects of K43N and K43T mutations on Car production were partially alleviated by provision of an excess of the quorum-sensing signalling molecule N-(3-oxohexanoyl)-L-homoserine lactone. Finally, a proteomic analysis of the K43T mutant indicated that the abundance of a subset of intracellular proteins was affected by this rpsL mutation.

Streptomycin resistance in Clavibacter michiganensis subsp. michiganensis strains from Chile is related to an rpsL gene mutation

“…These effects are influenced by the type of mutation and the resulting synthetized amino acid. Reduced fitness was reported in asparagine and threonine mutants of E. carotovora and E. amylovora , whereas arginine mutants seem to be nonrestrictive (Chiou & Jones, ; Barnard et al ., ). According to the present analyses, Chilean Cmm resistant strains are arginine mutants.…”

“…Nevertheless, the repeated use of streptomycin for control of pathogenic bacteria has led to an increased antibiotic resistance, due to gene mutations and selection of resistant bacteria (Moller et al ., ). A number of streptomycin‐resistant plant pathogenic bacteria have been reported in different countries, including E. amylovora (Loper et al ., ; McManus & Jones, ; Chiou & Jones, ; Manulis et al ., ; Russo et al ., ), Erwinia carotovora (Barnard et al ., ), P. syringae pv. papulans (Burr et al ., ; Jones et al ., ), P. syringae pv.…”

“…Plant Pathology (2019) 68, 426-433 streptomycin-resistant plant pathogenic bacteria have been reported in different countries, including E. amylovora (Loper et al, 1991;McManus & Jones, 1994;Chiou & Jones, 1995;Manulis et al, 2003;Russo et al, 2008), Erwinia carotovora (Barnard et al, 2010), P. syringae pv. papulans (Burr et al, 1988;Jones et al, 1991), P. syringae pv.…”

Bacteriophage Resistance Mechanisms in the Fish Pathogen Flavobacterium psychrophilum: Linking Genomic Mutations to Changes in Bacterial Virulence Factors

“…For example, studies using insertional mutagenesis conferred phage resistance in Listeria monocytogenes, locating a transposon insertion upstream of coding regions (62). Besides, we cannot rule out the pleiotropic effect of other mutations on phenotypic diversity (phage resistance and virulence) in F. psychrophilum, as has been observed in Pseudomonas aeruginosa (63) and Erwinia carotovora (64). Finally, it is important to note that although the mutational changes in the resistant strains point in the same direction and can be linked to potentially phage-related genes and phenotypic properties of the strains, we do not have sequenced isolates from the control cultures without phages and therefore cannot completely rule out that similar mutations may have taken place even in the absence of phages.…”

Genetic transformation of Veillonella parvula

“…It has been reported in other bacteria that spontaneous mutations in the rpsL gene can confer streptomycin resistance (Shima et al, 1996;Bjorkman et al, 1998;Barnard et al, 2010). To generate a selective marker for testing the transformability of V. parvula PK1910, we isolated spontaneous streptomycin-resistant mutants and sequenced the rpsL gene of these mutants.…”