Research report: Elicitation of chitinases and anthraquinones inMorinda citrifoliacell cultures

The induction of stress metabolites by endogenous and exogenous elicitors found in plant‐microorganism interactions has been studied in Morinda citrifolia suspension cultures. Chitin 50, a water soluble chitin derivative, and chitosans as constituents of microbial cell walls were used as models for an exogenous elicitor. Addition of commercial pectic acid or pectins derived from Morinda citrifolia plant cell walls to plant cell culture media simulated the presence of endogenous elicitors. Chitin 50 was found to induce chitinase and anthraquinone synthesis, and Morinda citrifolia derived pectins were highly active in stimulating plant stress response. The elicitor effect of the polysaccharides applied was also found to be time dependent. The initial defense mechanism was induced by pectins and resulted in increasing chitinase and lysozyme activities. The next step of defense mechanism was predominantly induced by pectins causing enhanced production of anthraquinones initiated by pectins, chitosans and especially by Chitin 50.