Lon Protease Influences Antibiotic Production and UV Tolerance of Pseudomonas fluorescens Pf-5

AUTOR(ES)

Whistler, Cheryl A.

FONTE

American Society for Microbiology

RESUMO

Pseudomonas fluorescens Pf-5 is a soil bacterium that suppresses plant pathogens due in part to its production of the antibiotic pyoluteorin. Previous characterization of Pf-5 revealed three global regulators, including the stationary-phase sigma factor ςS and the two-component regulators GacA and GacS, that influence both antibiotic production and stress response. In this report, we describe the serine protease Lon as a fourth global regulator influencing these phenotypes in Pf-5. lon mutants overproduced pyoluteorin, transcribed pyoluteorin biosynthesis genes at enhanced levels, and were more sensitive to UV exposure than Pf-5. The lon gene was preceded by sequences that resembled promoters recognized by the heat shock sigma factor ς32 (ςH) of Escherichia coli, and Lon accumulation by Pf-5 increased after heat shock. Therefore, ςH represents the third sigma factor (with ςS and ς70) implicated in the regulation of antibiotic production by P. fluorescens. Lon protein levels were similar in stationary-phase and exponentially growing cultures of Pf-5 and were not positively affected by the global regulator ςS or GacS. The association of antibiotic production and stress response has practical implications for the success of disease suppression in the soil environment, where biological control organisms such as Pf-5 are likely to encounter environmental stresses.

Documentos Relacionados

• Characterization of the Pyoluteorin Biosynthetic Gene Cluster of Pseudomonas fluorescens Pf-5
• Positive Autoregulation and Signaling Properties of Pyoluteorin, an Antibiotic Produced by the Biological Control Organism Pseudomonas fluorescens Pf-5
• The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5.
• A global regulator of secondary metabolite production in Pseudomonas fluorescens Pf-5.
• The Two-Component Regulators GacS and GacA Influence Accumulation of the Stationary-Phase Sigma Factor ςS and the Stress Response in Pseudomonas fluorescens Pf-5