Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two ge...Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato （Pst） DC3000 and Xanthomonas oryzae pv. oryzae （Xoo） PXO99A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-l-carboxylic acid （PCA） of Pst DC3000 accumulated to 13.4 IJg L-1, while that of Xoo PXO99A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL-1 PCA, while Xoo PXO99A was sensitive to 50 IJg mL ~ PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.展开更多
[ Objective ] The paper was to construct bait vector pGBKTT-Lescpth5, and detect its self-activated transcription activity and the toxicity on yeast cells. [ Method] Lescpth5 was amplified by PCR technique, and connec...[ Objective ] The paper was to construct bait vector pGBKTT-Lescpth5, and detect its self-activated transcription activity and the toxicity on yeast cells. [ Method] Lescpth5 was amplified by PCR technique, and connected into bait vector pGBKTT. The recombined vector was transformed into yeast competent ceils AH109 and carried out self-activated detection and toxicity detection in the au.xotrephic medium. [ Result] Digestion and sequencing results showed that bait vector pGBKT7-Lescpth5 was suecessfully constructed with correct reading frame. Self-activated activity and toxicity detection results showed that bait vector had no self- activated activity on yeast strain AH109, which also had no toxicity on yeast. [Condusion] Bait vector successfully constructed could be used in yeast two-hybrid system, which laid the foundation for screening of cDNA library in the next step.展开更多
基金supported by the grants from the Genetically Modified Organisms Breeding Major Projects, China (2014ZX0800905B)the Fundamental Research Funds for the Central Universities, Chinathe Program for New Century 151 Talents of Zhejiang Province, China
文摘Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato （Pst） DC3000 and Xanthomonas oryzae pv. oryzae （Xoo） PXO99A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-l-carboxylic acid （PCA） of Pst DC3000 accumulated to 13.4 IJg L-1, while that of Xoo PXO99A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL-1 PCA, while Xoo PXO99A was sensitive to 50 IJg mL ~ PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.
基金Supported by Natural Science Foundation of Beijing (6012017)Dr. Funding of Xinjiang Production and Construction Corps~~
文摘[ Objective ] The paper was to construct bait vector pGBKTT-Lescpth5, and detect its self-activated transcription activity and the toxicity on yeast cells. [ Method] Lescpth5 was amplified by PCR technique, and connected into bait vector pGBKTT. The recombined vector was transformed into yeast competent ceils AH109 and carried out self-activated detection and toxicity detection in the au.xotrephic medium. [ Result] Digestion and sequencing results showed that bait vector pGBKT7-Lescpth5 was suecessfully constructed with correct reading frame. Self-activated activity and toxicity detection results showed that bait vector had no self- activated activity on yeast strain AH109, which also had no toxicity on yeast. [Condusion] Bait vector successfully constructed could be used in yeast two-hybrid system, which laid the foundation for screening of cDNA library in the next step.
