Global metabolic changes by Bacillus cyclic lipopeptide extracts on stress responses of para rubber leaf

Abstract

Abstract The changing environmental conditions generate the abiotic stress like exposing of chemicals and biotic stress like Phytophthora palmivora infection which is causes leaf fall disease affecting the growth rate of para rubber seedlings resulting in economic loss. To prevent abiotic and biotic stresses, biocontrol agents like cyclic lipopeptides (CLPs) from Bacillus spp. have been introduced to reduce the usage of chemically synthesized fungicides and fertilizers. This study aimed to use Bacillus CLP extracts as a biological agent to stimulate the plant growth system in para rubber seedlings comparing with an exogenous plant hormone (salicylic acid; SA) using untargeted metabolomics. CLP extracts were obtained from B. subtilis PTKU12 and exogenous SA that were each applied on the leaves of para rubber seedlings. The expressed metabolic network responding to stress induced by exposing of different agents was analyzed using liquid chromatography-tandem mass spectrometry. There were 1,702 and 979 metabolites which were detected in positive and negative ion modes of electrospray ionization, respectively. The application of CLP extracts showed the greatest accumulation of up-regulated metabolite changes in the leaves belonging to 56 metabolic pathways. The analysis of metabolic pathways indicated that CLP extracts played an important role in alanine, aspartate and glutamate metabolism to stress response leading to plant growth promotion. These findings revealed the effect of Bacillus CLP extracts on plant growth promotion considering as a protective option for para rubber plantation.