RT Journal Article
SR Electronic
T1 Host-selected mutations converging on a global regulator drive an adaptive leap by bacteria to symbiosis
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 067025
DO 10.1101/067025
A1 M. Sabrina Pankey
A1 Randi L. Foxall
A1 Ian M. Ster
A1 Lauren A. Perry
A1 Brian M. Schuster
A1 Rachel A. Donner
A1 Matthew Coyle
A1 Vaughn S. Cooper
A1 Cheryl A. Whistler
YR 2016
UL http://biorxiv.org/content/early/2016/07/31/067025.abstract
AB Even though eukaryote health relies on beneficial symbionts, host defenses targeting pathogens create substantial obstacles for the establishment of these essential partnerships. To reveal mechanisms of symbiotic adaptation, we experimentally evolved ecologically distinct bioluminescent Vibrio fischeri through Euprymna scolopes squid light organs. Serial passaging of V. fischeri populations through squid hosts produced eight distinct mutations in the binK sensor kinase gene that conferred an exceptional selective advantage demonstrated through both empirical and theoretical analysis. Squid-adaptive binK alleles promoted colonization and immune evasion behavior which was mediated by symbiotic polysaccharide (Syp). binK variation also produced metabolic convergence with native symbionts, and altered quorum sensing and luminescence. Preexisting coordination of symbiosis traits facilitated an efficient solution where altered function of a regulator was the key to unlock multiple colonization barriers. These results identify a genetic basis for microbial adaptability and underscore the importance of hosts as selective agents that shape emergent symbiont populations.Impact statement Squid selection on non-native Vibrio fischeri drove rapid adaptation through convergent mutations of large effect, unmasking preexisting coordinate regulation of symbiosis.Major subject areas, keywords, and research organism(s)Major subject area: Genomics and evolutionary biology