In through the Out Door: A Functional Virulence Factor Secretion System Is Necessary for Phage Infection in Ralstonia solanacearum
André da Silva Xavier, Alessandra Gonçalves de Melo, Connor G. Hendrich, Denise M. Tremblay, Geneviève M. Rousseau, Pier-Luc Plante, Katrina T. Forest, Poliane Alfenas‐Zerbini, Caitilyn Allen, Sylvain Moineau
Abstract
Ralstonia solanacearum is a destructive plant pathogen that causes lethal bacterial wilt disease in hundreds of diverse plant hosts, including many economically important crops. Phages that kill R. solanacearum could offer effective and environmentally friendly wilt disease control, but only if the bacterium cannot easily evolve resistance. Encouragingly, most R. solanacearum mutants resistant to the virulent lytic phage phiAP1 no longer secreted multiple virulence factors and had much reduced fitness and virulence on tomato plants. Further analysis revealed that phage phiAP1 needs a functional type II secretion system to infect R. solanacearum, suggesting this podophage uses a novel infection mechanism.