Co-Authors:
Sathiyabama, M., Department of Plant Science, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
Bernstein, N., Institute of Soil Water and Environmental Sci, Volcani Center, POB 6, Bet-Dagan, Israel
Anusuya, S., Department of Plant Science, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
Abstract:
Curcumin, the major secondary metabolite of turmeric plants is used for centuries as a dye, medicine and flavoring agent. Its production in the plant varies between genotypes and environmental conditions, and for improved industrial commercialization, there is a need to increase and standardize its production in the plant. Biosynthesis of secondary metabolites are affected by biotic and abiotic elicitors. Chitosan is a nontoxic, natural and biodegradable polymer that is known to elicit defense responses in plants and to stimulate plant development, processes that involve changes to the metabolite profile of plants. Little is known about the potential of chitosan to alter the chemical profile of the plant and especially to stimulate secondary metabolite production. The present study identified its potential as an exogenous elicitor for stimulated bioaccumulation of curcumin, in turmeric. Tumeric plants, cultivated in a greenhouse, were sprayed every 30 days with water (control) or 0.1% chitosan solution. The chitosan treatment increased the production of curcumin in the rhizomes, by 100%, by stimulation of curcumin bioaccumulation in the rhizome tissue, by 56%, as well as rhizome development, by 38%. This dual stimulation response was accompanied by increased activity of the defense enzymes peroxidase, polyphenol oxidase, and β-1,3glucanases. Furthermore, the chitosan-elicited increase in activity of protease inhibitor in the leaves and the rhizomes correlated developmentally with the appearance of new isoforms of the protein. These results demonstrate that this eco-friendly compound can be used to stimulate curcumin production in turmeric for industrial endeavours, and points at its potential as a defence elicitor. © 2016 Elsevier B.V.