Recruitment of a Lineage-Specific Virulence Regulatory Pathway Promotes Intracellular Infection by a Plant Pathogen Experimentally Evolved into a Legume Symbiont.

摘要: Ecological transitions between different lifestyles, such as pathogenicity, mutualism and saprophytism, have been very frequent in the course of microbial evolution, often driven by horizontal gene transfer. Yet, how genomes achieve ecological transition initiated transfer complex biological traits remains poorly known. Here, we used experimental genomics, transcriptomics high-resolution phenotyping to analyze evolution plant pathogen Ralstonia solanacearum into legume symbionts, following a natural plasmid encoding essential mutualistic genes. We show that regulatory pathway recipient R. genome involved extracellular infection hosts was reused improve intracellular symbiosis with Mimosa pudica legume. Optimization capacity gained through mutations affecting two components new pathway, transcriptional regulator efpR region upstream from RSc0965-0967 genes unknown functions. Adaptive caused downregulation over-expression downstream module, three RSc3146-3148, which proteins likely associated membrane. This led important metabolic transcriptomic changes drastic qualitative quantitative improvement nodule infection. In addition, these adaptive decreased virulence original pathogen. The complete efpR/RSc3146-3148 could only be identified pathogenic species complex. Our findings illustrate rewiring genetic network regulating allows radically type symbiotic interaction contributes trade-offs.