Colchicine-induced Jasminum sambac Polyploids Secured Altered Metabolic Profile with Unique Antifungal Compounds

Abstract Cercospora leaf spot is one of the critical foliar fungal diseases of jasmine, which causes considerable yield losses. There are no cultivars or germplasm accessions that are resistant to this infection and hence fungicide usage is the mainstay of management of this disease, which poses a hazard to the environment. Polyploidization is one of the key breeding methods in jasmine as newly obtained polyploids may have increased resistance/tolerance to diseases owing to altered metabolite production. In the present study, seventeen putative polyploids were obtained from Jasminum sambac Cv. Ramanathapuram Gundumalli by treating with the polyploidizing agent, colchicine. Among them, two mutant plants (generated from the wild parent following treatment with 0.25% colchicine) exhibited no symptoms for Cercospora leaf spot, whereas the control had the highest mean PDI (63.65%). Non-targeted metabolite profiling experiment indicated that couple of antifungal compounds (such as 1H-1,2,4-Triazole-1-ethanol, α-butyl-α-(2,4-dichlorophenyl) and Dasycarpidan-1-methanol, acetate (ester)) were present only in the two newly evolved mutants of J. sambac and absent in wild parent. Molecular docking results have shown that the compound Dasycarpidan-1-methanol, acetate (ester) binds effectively with two fungal proteins 7EUS and 7EUT, which are actively involved in biosynthesis of cercosporin (which is a photoactivated toxin that uses reactive oxygen species (ROS) in host cells and damage cell components such as membranes, proteins and lipids). Thus, this study enabled the development of a natural and eco-friendly method of evolving and characterizing novel lines in jasmine, which would have potential applications in flower industry.