Bacillus amyloliquefaciens MBI600 differentially induces tomato defense signaling pathways depending on plant part and dose of application
A study published in Scientific Reports by researchers from the University of Crete, the Institute of Molecular Biology and Biotechnology, and BASF SE explored how the beneficial bacterium Bacillus amyloliquefaciens MBI600 activates natural defense pathways in tomato plants depending on how and where it is applied .
B. amyloliquefaciens is widely used in biological control because it can suppress plant pathogens and promote crop resilience. In this study, scientists examined how its commercial formulation, Serifel, triggers systemic resistance in tomatoes. They found that the plant’s response varied based on the dose and application method – whether sprayed on leaves or drenched through the roots.
At lower doses, Serifel primarily activated salicylic acid (SA)-related defense genes, while higher doses stimulated a synergistic interaction between the jasmonic acid (JA) and ethylene (ET) signaling pathways alongside SA. This cross-talk enhanced the expression of multiple defense-related genes, including erf1, loxD, npr1, and pr1b1.
The research also showed that beneficial microbes like MBI600 can trigger mild but effective immune responses without harming the plant’s metabolism. When plant tissues were saturated with bacterial elicitors, over 24 defense-associated genes were activated, including those linked to antioxidant production, stress tolerance, and hormonal signaling.
These findings highlight the dual benefits of B. amyloliquefaciens – directly controlling pathogens while priming plants for stronger immunity – making it a valuable tool for sustainable greenhouse and open-field crop production.