Chitosan or yeast extract enhance the accumulation of eight phenolic acids in cell suspension cultures ofMalus×domesticaBorkh.

SummaryThe effects of chitosan or a yeast extract on the production of secondary metabolites and on the induction of plant defence responses in cell suspension cultures of Malus × domestica Borkh. were investigated. Chitosan or yeast extract enhanced the production of phenolic acids by 1.5-fold and by 2.0-fold after 3 d of culture following elicitor treatment, respectively, compared to untreated control cell suspension cultures. The production of specific phenolic acids responded differently to chitosan and to yeast extract. Among the dominant phenolic acids, the production of p-coumaric acid was stimulated by chitosan and by yeast extract up to 10.3-fold and 5.1-fold within 3 d, respectively, compared with the concentration in control cultures within 3 d. Chlorogenic acid concentrations were increased 2.7-fold within 3 d of culture by yeast extract treatment compared to the controls. There was no difference in the amount of phenolic acids released into the culture medium between control and elicitor-treated cultures, indicating that these elicitors had no effect on the release or transport of phenolic acids. In addition, phenylalanine ammonia-lyase (PAL) activity was reduced up to 33% by elicitation. While yeast extract maintained control levels of cell growth in culture, chitosan inhibited cell growth in culture by 72%.