Evaluation of fluorescence-activated cell sorting technology in agrobacterium biocontrol

Fluorescence-activated cell sorting (FACS) as a novel and sensitive technology was used to evaluate the biocontrol efficiency of Bacillus subtilis against Agrobacterium tumefaciens, a very destructive plant pathogen. The combination of two methods of culturing and cell sorting by FACS technology was used to distinguish a rapid and accurate method in monitoring the biocontrol effect of Bacillus (ATCC21332) on Agrobacterium (IBRC-M10701 and AGL1),. The culture method indicated that the B. subtilis could suppress A. tumefaciens in vitro and in vivo. We used a green fluorescent protein (GFP), reporter, to flow cytometric analysis using FACS. The mean of GFP expression levels was significantly reduced to 17.98, 16.48, and 11.27% in treatments 24, 48, and 72 h post-treatment; however, it was 31.57, 26.06, and 23.98% in the nontreated ones. The experiments demonstrated a positive biocontrol effect of Bacillus against Agrobacterium. Overall, our findings may provide a basis for improving the new rapid biocontrol agent detection method based on FACS.