Journal of Plant Pathology (2021) 103, 99-108

Mireia Marcé Escursell, Alexia Roschi, Theo H.M. Smits and Fabio Rezzonico (2021)
Characterization and direct molecular discrimination of rpsL mutations leading to high streptomycin resistance in Erwinia amylovora
Journal of Plant Pathology 103 (1 suppl.), 99-108
Abstract: Erwinia amylovora can rapidly become highly resistant to applications of the antibiotic streptomycin through a single nucleotide mutation in the rpsL gene, which causes an amino acid substitution that prevents inhibitory binding of streptomycin while preserving the functionality of the ribosome. Several viable mutations are described in the literature, but screenings in the orchards consistently revealed that the one leading to the substitution of lysin by arginine at position 43 (K43R) is by far the most abundant. In this work, we tested the rate of emergence of the various spontaneous mutants, their tolerance to different antibiotic concentrations and their general fitness in competition experiments. Furthermore, we developed a molecular assay based on the SNaPshot™ Multiplex Kit from Thermo Fisher Scientific that allows swift determination of rpsL mutations using a single-base primer extension approach directly from colonies on plate. Or results indicate that the prevalence of variant K43R is largely due to fact that it retains the highest environmental fitness even in absence of antibiotic pressure. Sequence analysis of two resistant colonies that did not respond as expected in the SNaPshot™ assay revealed the existence of two yet undescribed rpsL mutations resulting in conditional-lethal streptomycin-dependent (Sm^D) phenotypes, which are unable to grow in absence of the antibiotic.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Fabio Rezzonico

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Erwinia amylovora		Switzerland