Role of Vfr in the regulation of antifungal compound production by Pseudomonas fluorescens FD6.
Pseudomonas fluorescens FD6 has been shown to possess many beneficial traits involved in the biocontrol of fungal plant pathogens, such as Botrytis cinerea and Monilinia fructicola. Vfr (virulence factor regulator) a highly conserved global regulator of gram-negative bacteria, such as the human pathogen Pseudomonas aeruginosa, is required for the expression of many important virulence traits. The role of Vfr in the regulation of biocontrol traits, such as the production of antibiotics to control fungal pathogens by antagonistic bacteria, has not been elucidated. This study investigated the effect of a vfr mutant derived from P. fluorescens FD6 to better understand the regulation of some important biocontrol traits associated with the bacterium. Biochemical studies indicated that the production of the antibiotics 2,4-diacetylphloroglucinol, pyrrolnitrin and pyoluteorin, was markedly enhanced in the vfr mutant. The vfr mutation also increased biofilm production, swimming motility and the expression of exopolysaccharide-associated gene (pelA, pslA and pslB) transcripts, but reduced protease production. Wheat rhizosphere and root tip colonization by the vfr mutant was higher than that by the wild type at 7 and 21days after inoculation. These findings demonstrate that Vfr modulates the expression of several key traits and the production of important antibiotics involved in the biocontrol potential of P. fluorescens FD6.
College of Plant Protection and Horticulture, Yangzhou University, Yangzhou 225009, PR China. Electronic address: zqx817@sohu.com.
Qingxia
Q
Zhang
College of Plant Protection and Horticulture, Yangzhou University, Yangzhou 225009, PR China.
Yanyan
Y
Ji
College of Plant Protection and Horticulture, Yangzhou University, Yangzhou 225009, PR China.
Qi
Q
Xiao
Plant and Food Research Private Bag 4704, Christchurch 8140, New Zealand.
Soonie
S
Chng
College of Plant Protection and Horticulture, Yangzhou University, Yangzhou 225009, PR China.
Yunhui
Y
Tong
College of Plant Protection and Horticulture, Yangzhou University, Yangzhou 225009, PR China.
Xijun
X
Chen
Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, PR China.
Fengquan
F
Liu
D000898:Antibiosis; D000935:Antifungal Agents / Q000378:metabolism*; D002373:Cyclic AMP Receptor Protein / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D006801:Humans; D010572:Pest Control, Biological; D010636:Phenols / Q000378:metabolism*; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D011758:Pyrroles / Q000378:metabolism*; D011764:Pyrrolnitrin / Q000378:metabolism*; D012988:Soil Microbiology; D014908:Triticum / Q000382:microbiology
D000935:Antifungal Agents; D002373:Cyclic AMP Receptor Protein; D010636:Phenols; D011758:Pyrroles; C095503:pyoluteorin; C059817:2,4-diacetylphloroglucinol; D010696:Phloroglucinol; D011764:Pyrrolnitrin
Antifungal compound; Biocontrol; Pseudomonas; Vfr