Evaluation of the symbiotic performance of tomato plants inoculated with Bacillus velezensis NKG-2 and challenged with Fusarium wilt pathogen

There has been an increased interest in investigating how plants interact with microbes by inoculation of bacteria that promote plant growth. In this study, the effect of co-inoculation of tomato seedlings with B. velezensis NKG-2 and induction of plant defense response against F. oxysporum f. sp. lycopersici was assessed in greenhouse assay. This antagonistic strain protected tomato plants from the detrimental effect of Fusarium oxysporum f. sp. lycopersici, reducing the Fusarium wilt incidence. The plant fitness parameters (total chlorophyll and shoot nitrogen contents) from the plants inoculated with NKG-2 and fungal-pathogen-challenged plants were significantly higher than those in un-inoculated challenged plants. NKG-2-inoculated plants improved its root surface colonisation by forming biofilm-like structures and protected the plants against infectious pathogens. The results showed in this work will help to expand our understanding of the mode of action of NKG-2 as a biological control agent and consequently, its application in agriculture.