ABA analogue produced by Bacillus marisflavi modulates the physiological response of Brassica juncea L. under drought stress

The present study aims to understand the molecular mechanism involved in beneficial rhizobacteria mediated alleviation of drought stress host plant. Bacillus marisflavi CRDT-EB-1 isolated from rhizosphere soil was found effective inducing resistance against mustard seedlings. Among different bacterial derivatives tested, culture filtrate contain bioactive molecules. Solvent extract yielded seven distinct bands/fractions on thin layer chromatography (TLC). fraction four (F4) with Rf value 0.35–0.40 significant reducing adverse effect plants. Application F4 resulted delayed drooping point and higher tolerance index (3.34), induced stomatal closure (9.648 μ), seed germination inhibition (12%), reduced GA3 α-amylase activity germinating barley seeds. On TLC, turned colorless orange color upon spray 2,4-dinitrophenylhydrazine reagent indicated presence aldehyde group. Supporting this, peaks between 9.8 10.0 ppm 1H NMR chromatogram confirmed Upon LC-MS/MS analysis a crude revealed compounds mass 250.33 266.33. By analyzing these data, identity predicted as xanthoxin xanthoxic acid, which are well-known precursor Abscisic acid (ABA) concludes capability ABA analogue (xanthoxin like compounds) production by B. its involvement