摘要：SummaryBacillus subtilisis known to promote plant growth and protect plants against disease.B. subtilisrapidly adapts toArabidopsis thalianaroot colonization, as evidenced by improved root colonizers already after 12 consecutive transfers between seedlings in a hydroponic setup. Re-sequencing of single evolved isolates and endpoint populations revealed mutations in genes related to different bacterial traits, in accordance with evolved isolates displaying increased root colonization associated with robust biofilm formation in response to the plant polysaccharide xylan and impaired motility. Interestingly, evolved isolates suffered a fitness disadvantage in a non-selective environment, demonstrating an evolutionary cost of adaptation to the plant root. Finally, increased root colonization by an evolved isolate was also demonstrated in the presence of resident soil microbes. Our findings highlight how a plant growth-promoting rhizobacterium rapidly adapts to an ecologically relevant environment and reveal evolutionary consequences that are fundamental to consider when evolving strains for biocontrol purposes.Graphical abstractDisplay OmittedHighlights•Bacillus subtilisshows fast adaptation toArabidopsis thalianaroots in a hydroponic setup•Evolved isolates exhibit robust biofilms in response to xylan and impaired motility•Adaptation toA. thalianaroots is accompanied by an evolutionary cost•An evolved isolate shows higher root colonization in the presence of soil bacteriaEcology; Microbiology; Plant biology.
