The ability of Pseudomonas sp. LBUM 223 to produce phenazine-1-carboxylic acid affects the growth of Streptomyces scabies, the expression of thaxtomin biosynthesis genes and the biological control potential against common scab of potato

Abstract

Streptomyces scabies causes common scab, an economical disease affecting potato crops world-wide, for which no effective control measure exists. This pathogen produces the plant toxin thaxtomin A, which is involved in symptom development on potato tubers. A biological control approach that can limit S. scabies growth and repress thaxtomin production represents an attractive alternative to classical control strategies. Pseudomonas sp. LBUM 223 produces phenazine-1-carboxylic acid (PCA), an antibiotic that inhibits the growth of plant pathogens and contributes to the biological control of plant diseases. In this study, the involvement of LBUM 223's PCA-producing ability in the growth inhibition of S. scabies, repression of thaxtomin biosynthesis genes (txtA and txtC) and the biological control of common scab of potato was investigated using a mutant defective in PCA production (LBUM 223phzC(-) ). Streptomyces scabies growth was inhibited to a significantly lesser degree by LBUM 223phzC(-) than by the wild type. LBUM 223 also significantly repressed txtA and txtC expression in S. scabies and protected potato against disease, whereas LBUM 223phzC(-) did not. These results suggest that PCA production is central to the ability of LBUM 223 to limit pathogen growth, repress the expression of key pathogenicity genes and control common scab of potato.

Long-Term Induction of Defense Gene Expression in Potato by Pseudomonas sp. LBUM223 and Streptomyces scabies

“…LBUM223 was previously isolated from the rhizosphere of strawberry plants in Bouctouche, NB, Canada (28). An isogenic mutant of LBUM223, LBUM223 phzC-, incapable of producing PCA, was generated and validated as previously described (36). All strains were routinely grown in tryptic soy broth (BD, Franklin Lakes, NJ) with shaking at 25°C.…”

Adsorption/desorption characteristics, separation and purification of phenazine‐1‐carboxylic acid from fermentation extract by macroporous adsorbing resins

“…Among the PCA‐producing bacterial genera, Pseudomonas and Streptomyces have been extensively studied as biological control agents . PCA exerts a curative effect on many crop fungal diseases, including cucumber anthracnose, ginger rhizome rot, potato scab, pepper Phytophthora blight and wheat take‐all disease . PCA and PCA‐producing strains are substantially employed as biocontrol agents because of their potential fungicidal efficiency, minimum toxicity status, and biodegradability.…”

Improved High-Quality Draft Genome Sequence of Pseudomonas fluorescens KENGFT3

“…KENGFT3 had genome comparison metrics that placed it below the identified cutoff for inclusion in the same species as P. fluorescens SBW25. However, P. fluorescens strain LBUM223 (5), which shares certain phenotypic attributes with KENGFT3 (6, 7), had genome comparison metrics that placed these two strains within the same species (average nucleotide identity [ANI], 99.39%). Calculation of a phylogenetic distance tree using 60 strains of P. fluorescens annotated at the Integrated Microbial Genomes portal (https://img.jgi.doe.gov/cgi-bin/mer/main.cgi) revealed that P. fluorescens KENGFT3 and LBUM223 clustered with P. fluorescens strains GcM5-1A and UK4.…”