Premium
Spontaneous mutations in a regulatory gene induce phenotypic heterogeneity and adaptation of Ralstonia solanacearum to changing environments
Author(s) -
Perrier Anthony,
Barlet Xavier,
Rengel David,
Prior Philippe,
Poussier Stéphane,
Genin Stéphane,
Guidot Alice
Publication year - 2019
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14717
Subject(s) - biology , ralstonia solanacearum , phenotype , mutant , gene , genetics , virulence , adaptation (eye) , pathogen , genetic heterogeneity , genetic fitness , wild type , regulator , neuroscience
Summary An evolution experiment with the bacterial plant pathogen Ralstonia solanacearum revealed that several adaptive mutations conferring enhanced fitness in plants arose in the efpR gene encoding a regulator of virulence and metabolic functions. In this study, we found that an efpR mutant systematically displays colonies with two morphotypes: the type S (‘smooth’, similar to the wild type) and the type EV (‘ efpR variant’). We demonstrated that the efpH gene, a homologue of efpR , plays a key role in the control of phenotypic heterogeneity, the Δ efpR ‐Δ efpH double mutant being stably locked into the EV type. Using mixed infection assays, we demonstrated that the type EV is metabolically more proficient than the type S and displays fitness gain in specific environments, whereas the type S has a better fitness into the plant environment. We provide evidence that this efpR ‐dependent phenotypic heterogeneity is a general feature of strains of the R. solanacearum species complex and could occur in natural conditions. This study highlights the potential role of phenotypic heterogeneity in this plant pathogen as an adaptive trait to changing environments.