African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12275

Full Length Research Paper

Enhancing the production of syringomycin E in Pseudomonas syringae pv syringae by random mutagenesis and molecular characterization of the SyrB1 gene

Nguyen Hai Trieu
  • Nguyen Hai Trieu
  • Molecular Microbiology Laboratory, Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Rd,Cau Giay, Hanoi, Vietnam
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Nguyen Ngoc Huyen
  • Nguyen Ngoc Huyen
  • Post Harvested Biotechnology Laboratory, Vietnam Institute of Agricultural Engineering and Post-Harvest Technology, Vietnam
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Nguyen Huong Tra
  • Nguyen Huong Tra
  • Post Harvested Biotechnology Laboratory, Vietnam Institute of Agricultural Engineering and Post-Harvest Technology, Vietnam
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Nguyen Thi Hong Ha
  • Nguyen Thi Hong Ha
  • Food Technology and Nutrition Discipline, School of Science, RMIT University, GPO Box 2476 Melbourne VIC 3001, Australia
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Harsharnjit S Gill
  • Harsharnjit S Gill
  • Post Harvested Biotechnology Laboratory, Vietnam Institute of Agricultural Engineering and Post-Harvest Technology, Vietnam
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Nguyen Minh Huong
  • Nguyen Minh Huong
  • Molecular Microbiology Laboratory, Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Rd,Cau Giay, Hanoi, Vietnam
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Dong Van Quyen
  • Dong Van Quyen
  • University of Science and Technology of Ha Noi, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Rd,Cau Giay, Hanoi, Vietnam
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  •  Received: 19 October 2016
  •  Accepted: 21 March 2017
  •  Published: 12 April 2017

Abstract

Syringomycin E (SRE) is a phytotoxin produced by Pseudomonas syringae pv syringae with high potential as a safe and effective therapy for the control of human fungal infections and as a preservative for the food industry. In this study, 27 strains of P. syringae pv syringae were isolated from plums, potatoes, apricots and peaches, of which P. syringae pv syringae 120 (PS120) showed the highest SRE production levels. Furthermore, random mutagenesis induced by ultraviolet (UV) radiation resulted in the generation of a P. syringae pv syringae mutant that produced 30% more SRE than the parental strain PS120. To elucidate molecular mechanism underlying the higher SRE production ability of the mutant strain, syrB1 and syrB2 genes, which are known to be involved in SRE production, were cloned and sequenced. The nucleotide and amino acid sequences analysis showed that UV radiation induced numerous mutations at the AMP binding site on adenylation domain of syrB1, while no mutation was detected in syrB2 gene. Real-time polymerase chain reaction (PCR) results showed that expression of syrB1 gene in mutant strain was six-fold higher than that of PS120 strain. Taken together, these results suggest that the mutations at AMP binding site and overexpression of syrB1 were responsible for increased biosynthesis of SRE in P. syringae pv syringae.

 

Key words: Antifungal protein, syringomycin E, UV mutagenesis, Pseudomonas syringae pv syringae, syrB1.