Enhancement of antifungal activity of Burkholderia pyrrocinia JK‐SH007 genetically modified with Bacillus subtilis Chi113 gene

Previous studies showed that Burkholderia pyrrocinia JK‐SH007 is a potential biocontrol agent of poplar canker disease. In this report, B. pyrrocinia JK‐SH007 was genetically modified by introducing the Bacillus subtilis Chi113 gene to enhance its antifungal activity. The green fluorescence of B. pyrrocinia JK‐SH007E1 can be detected because of its transformation with plasmid pHKT2‐Chi113 containing a gfp reporter gene. Real‐time quantitative PCR (qPCR) showed that the B. subtilis Chi113 gene was highly expressed in B. pyrrocinia JK‐SH007E1 at mRNA level. The chitinase activity and the antifungal activity of B. pyrrocinia JK‐SH007E1 were significantly increased, and the clear halo was visible on the colloidal chitin agar plate. In addition, the constructed recombinant plasmid pHKT2‐Chi113 was stably maintained for at least 100 generations in the absence of antibiotic selection in B. pyrrocinia JK‐SH007E1. In western blot analysis, the Chi113‐GFP fusion protein was detected in B. pyrrocinia JK‐SH007E1 using the GFP polyclonal antibody. In conclusion, the B. subtilis Chi113 gene was successfully transformed into B. pyrrocinia JK‐SH007 and was expressed both at mRNA level and protein level. Moreover, the antifungal activity of B. pyrrocinia JK‐SH007 was improved through this genetic modification.