Steroidal Plant Growth Promoters vs. Phytopathogens, via Enzymatic Regulation; An in Silico Approach

Steroidal plant growth promoters (SPGP) have been continuously studied due to their high activity increasing biomass and resistance to diverse stress fac-tors. In our hands, a new SPGP family of 22-oxocholestanic compounds stands out at a comparative level to brassinosteroids (BSs). The potential activity of new SPGP against phytopathogens was studied through in silico molecular docking, these assays were performed with relevant ensymes of phytopato-gens Chitinase B and 1,3-β-Glucanase. Nine Chitinase B inhibitors and two 1,3-β-Glucanase inhibitors were proposed. The launched study analyzed the interactional and spatial level, determining the presence of interactions with key amino acids in receptors in comparison to reference inhibitors. Even more, the AVR4 and ECP6 effectors were also examined. No compound that blocks ECP6 was found; due to, probably, the influence of its highly hydrophilic environment. In the case of AVR4, two SPGP showed a better docking score (DS) than a chitin fragment (endogenous ligand); this fact demonstrates the latent potential of the 22-oxocholestanic derivatives against phytopathogens, with a specific regulation via proliferation inhibition. Moreover, this SPGP does not affect the symbiotic fungi that are beneficial for the natural plant system.