Elicitation effects on biosynthesis of indole alkaloids by Catharanthus roseus leaves

Abstract

Two elicitors, chitosan and methyl jasmonate, were used for the study of elicitation effects on Catharanthus roseus leaves. Chitosan (DP 7190, MW 1200 kDa, and %DA 14) concentrations 0-30 ppm were daily sprayed over the aerial parts of the plants twice a day for 7 days in the first experiment set. Methyl jasmonate at concentrations 0 - 1000 ppm were daily fumed under the closed system over the aerial parts of each plant for 2 hours every day for 7 and 14 days in the second experiment set. Methyl jasmonate fuming resulted in significant induction of the biosynthesis of vindoline in C. roseus leaves, while little, if any, induction of vindoline formation occurred when exposured to chitosan. The optimal concentration of methyl jasmonate for elicitation of vindoline production was 100 ppm. The vindoline concentration was 2 mg/g leaf DW and 4 mg/g leaf DW after elicitation with 100-ppm methyl jasmonate for 7 and 14 days respectively (2 - 4 fold over concentration for unelicited condition). With the treatments of 0 - 100 ppm methyl jasmonate fuming for 14 days, vindoline accumulation in leaves increased linearly with methyl jasmonate concentration. The direct binding model of elicitor to receptor was well fitted with the data of vindoline accumulation in C. roseus responded to methyl jasmonate concentration