Computational Biology Approaches Revealing Novel Target in Vascular Wilt Pathogen Fusarium oxysporum f. sp. lycopersici for the Ligands of Marine Actinobacterial Origin

Abstract

In an in vitro study of antagonistic mangrove actinobacteria for its antifungal compounds to eliminate Fusarium oxysporum f. sp. lycopersici, the extracellular metabolites from the actinobacterium Kutzneria sp. strain TSII was documented. A total of 24 useful ligands were identified when profiled with Gas Chromatography-Mass Spectrometry after purification through silica gel column chromatography. Molecular modeling of Short-chain Dehydrogenases / Reductases (SDRs) was performed in the prime module of Schrodinger 2018-4 software using SDR of Bacillus anthracis as a template (PDB: 3I3OA). In silico studies utilizing the molecular docking of the 24 ligands with SDR responsible for pathogenicity, distributed on the membrane of the Fusarium oxysporum were carried out in Schrodinger 2018-4. Results were indicated as 1,4-Benzenedicarboxylic acid, Bis(2-ethylhexyl) ester, Spiro[Cyclopentane1,2’(1’H)-quinoxaline], Decanedioic acid, Didecyl ester with docking scores (Kcal/mol) of – 8.151, -7.231, - 6.031 and low binding free energy (ΔGb ) values (Kcal/mol) of – 68.11, -42.23, -79.41 respectively, relating to their potential use as antifungal agents in Fusarium wilt infections. As SDRs are involved in melanin biosynthesis, binding of these ligands may interfere with melanin biosynthetic pathways conferring pathogenicity to Fusarium oxysporum f. sp. lycopersici. Hence, the present research study uncovers in vitro antagonistic potential of marine actinobacterial metabolites towards the most devastating vascular wilt pathogen Fusarium oxysporum in tomatoes and identifies the probable involvement of SDR as the potential target in an in silico molecular docking approach.

Keywords

• short-chain dehydrogenase/reductases
• antifungals
• marine actinobacteria
• melanin biosynthesis
• fusarium oxysporum