Evolutionary Timeline and Genomic Plasticity Underlying the Lifestyle Diversity in <i>Rhizobiales</i>
Sishuo Wang, Andrew Meade, Hon‐Ming Lam, Haiwei Luo
Abstract
Bacteria form diverse interactions with eukaryotic hosts. This is well represented by the Rhizobiales , a clade of Alphaproteobacteria strategically important for their large diversity of lifestyles with implications for agricultural and medical research. To investigate their lifestyle evolution, we compiled a comprehensive data set of genomes and lifestyle information for over 1,000 Rhizobiales genomes. We show that the origins of major host-associated lineages in Rhizobiales broadly coincided with the emergences of their host plants/animals, suggesting bacterium-host interactions as a driving force in the evolution of Rhizobiales . We further found that, in addition to gene gains, preexisting traits and recurrent losses of specific genomic traits may have played underrecognized roles in the origin of host-associated lineages, providing clues to genetic engineering of microbial agricultural inoculants and prevention of the emergence of potential plant/animal pathogens.