Filamentous phages of Ralstonia solanacearum: double-edged swords for pathogenic bacteria

Abstract

Some phages from genus Inovirus use host or bacteriophage-encoded site-specific integrases or recombinases establish a prophage state. During integration or excision, a superinfective form can be produced. The three states (free, prophage, and superinfective) of such phages exert different effects on host bacterial phenotypes. In Ralstonia solanacearum, the causative agent of bacterial wilt disease of crops, the bacterial virulence can be positively or negatively affected by filamentous phages, depending on their state. The presence or absence of a repressor gene in the phage genome may be responsible for the host phenotypic differences (virulent or avirulent) caused by phage infection. This strategy of virulence control may be widespread among filamentous phages that infect pathogenic bacteria of plants.

Evolution of mutualism from parasitism in experimental virus populations

“…). Natural isolates of filamentous phages can also vary in their effects on their bacterial hosts (Yamada ), and our results highlight the need for a better understanding of how phage ecology affects the evolution of these interactions in nature.…”

Bacteriophages and Bacterial Plant Diseases

“…Here, phages form a non-lethal chronic infection with continuous production of progeny phages. However, suitability of these phages for biocontrol is questionable as their infection can have varying effects on host virulence, as shown with phytopathogen Ralstonia solanacearum with its phage ϕRSS1 causing increased virulence (Yamada, 2013), although it has been shown possible to isolate virulent filamentous phage (Kuo et al, 1994). Another undesirable property in a phage intended for biocontrol is the ability to bring about superinfection exclusion to its host during infection.…”

Application of filamentous phages in environment: A tectonic shift in the science and practice of ecorestoration

“…Filamentous phages control the emergence of bacterial pathogens through their effects on the physiology of their bacterial hosts (Table ; Figure ). Recombinant filamentous phages have been developed to target such bacterial phytopathogens as Pseudomonas ( P. putida , P. aeruginosa ), E. coli (Hagens & Bläsi, ), and Ralstonia solanacearum (Yamada, ) and filamentous phages have been genetically modified to be antagonistic toward bacterial pathogens through (a) expression of restriction endonucleases, (b) initiation of programmed cell death, (c) development of sensitivity to antimicrobial substances, and (d) development of oxidative burst in host cells (Table ).…”

“…Mostly, a phage infection enhances the host's ability to combat abiotic and biotic stress, to invade a new habitat, and to partake in the development of microbial communities (Askora & Yamada, ; Bille et al, ; Derbise & Carniel, ; Jian, Xiao, & Wang, ; Mai‐Prochnow et al, ; Rice et al, ; Shapiro et al, ; Waldor & Mekalanos, ; Webb, Lau, & Kjelleberg, ; Yu et al, ). However, at times a phage infection lowers the fitness of the host bacterium, which is also beneficial if the bacterial host happens to be a plant pathogen (Ahmad, Askora, Kawasaki, Fujie, & Yamada, ; Yamada, ). Filamentous phages are useful for manipulating bacteria for environmental applications because the phages are stably produced in their bacterial hosts and are easy to manipulate using genetic and chemical methods—however, they remain underexploited in current practice.…”