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.