Characterization of a novel Serratia fonticola EBS19 bacteria and investigation of its potential for biological control agent for botrytis cinerea

Botrytis cinerea is a plant pathogenic fungus that causes gray mold disease, which can cause economic loss of $100 billion worldwide. It has the ability to change its genetic structure and rapidly develop fungicide resistance used in agriculture. In addition to the desired inhibitory effect on the pathogen, biological control reduces the negative effects of chemicals that have harmful effects on the environment and human health used in control applications. In this study, it was determined that a Serratia fonticola bacterium, which can be used for biocontrol purposes against the pathogen, was isolated from the soil flora and had an antibiosis effect on the spore suspension of Botrytis cinerea. It was observed that the growth of the fungus spore was inhibited by the cell-free antibiosis effect of the metabolites released into the environment by treatment with phenol. The inhibition results on pathogen growth were confirmed by the results of the single layer agar and double layer agar experiments. By spectrophotometric analysis, optimum concentration (cell/ml), minimal inhibition concentration (MIC) and percent inhibition were determined. Compared to control group, in vitro tests showed an inhibition effect of 85% on day 3 and 65% on day 10 after inoculation. The bacterial strain was also identified as Serratia fonticola (EBS19) by whole-genome shotgun sequence analysis and the sequence data was submitted to NCBI (Acc. Nr: PRJNA788871). Comparative analyzes using the KEGG database classified genes encoding enzymes that play a suppressive role on pathogen growth, and their locations in the genome were determined for future gene-specific cloning studies. In in vitro experiments, the endoglucanase/cellulase enzymes are actively produced by the bacterial strain has also been verified. Additionally, Biolog analyses showed the specific carbon sources of the bacteria which will provide new insight for the preparation of effective biopreparate composition and its further application in vivo assays, which will direct us for applications expected in practice as promising candidate to be biological control agent.