Understanding the molecular basis on the biological suppression of bacterial leaf blight of anthurium exerted by Bacillus subtilis (BIO3) through proteomic approach.

We attempted to study the antibacterial activity of rhizospheric Bacillus spp., to curb the bacterial blight of anthurium caused by Xanthomonas axonopodis pv. dieffenbachiae (Xad). Twenty-eight bacterial isolates from rhizospheric regions were identified as different Bacillus spp. and Ochrobactrum sp. using 16S rRNA gene sequencing. B. subtilis BIO3 effectively inhibited the growth of Xad up to 1450.7 mm2, and extracted volatile organic metabolites from the isolate BIO3 inhibited the growth of Xad up to 1024 mm2. Tritrophic interaction of anthurium leaves bacterized with B. subtilis BIO3 and challenged with Xad resulted in the expression of 12 unique proteins compared to untreated control. Mascot Peptide Mass Fingerprint-based identification indicated that one was glutathione peroxidase, involved in defence mechanism, other six proteins were identified as leghemoglobin II, CTP synthase-like, predicted protein (Physcomitrella patens), centromere-associated protein E, grain size protein, and five proteins were hypothetical proteins. Foliar application with 1% liquid formulations (108 CFU/ml) of B. subtilis BIO3 significantly suppressed the bacterial leaf blight of anthurium up to 78% over untreated control and also increased the stem length and flower yield.