Diversification of the Type VI Secretion System in Agrobacteria
Chih‐Feng Wu, Alexandra J. Weisberg, Edward W. Davis, Lin Chou, Surtaz Khan, Erh‐Min Lai, Chih‐Horng Kuo, Jeff H. Chang
Abstract
The T6SS is used by several taxa of Gram-negative bacteria to secrete toxic effector proteins to attack others. Diversification of effector collections shapes bacterial interactions and impacts the health of hosts and ecosystems in which bacteria reside. We uncovered the diversity of T6SS loci across a genus of plant-associated bacteria and show that diversification is driven by the acquisition of new loci and reshuffling among species. However, linkages between specific subtypes of genes need to be maintained to ensure that proteins whose interactions are necessary to activate the T6SS remain together. Results reveal how organization of gene loci and domain structure of genes provides flexibility to diversify under the constraints imposed by the system. Findings inform on the evolution of a mechanism that influences bacterial communities.