Role of Chitinase and Chitin Oligosaccharides in Lignification Response of Cultured Carrot Cells Treated with Mycelial Walls

Abstract

Chitinase activity was induced in cultured carrot cells by incubation with mycelial walls of a fungus, Chaetomium globosum. Both intra- and extracellular chitinases were resolved into four components by gel filtration chromatography. The extracellular enzymes liberated soluble oligosaccharides of different sizes from insoluble chitin, suggesting that these carrot chitinases are endo-hydrolases. The solubilized chitinase digests obtained from insoluble mycelial walls of C. globosum and chitin were fractionated by gel filtration chromatography, and the elicitor activity of each fraction for the accumulation of phenolic acids in cultured carrot cells was determined. In both solubilized fragments of fungal walls and of chitin, elicitor-active oligosaccharides were distributed in many fractions, however, potent activity for inducing phenolic acid synthesis was observed in the high molecular weight fractions.