Purification and partial amino acid sequencing of a mycorrhiza-related chitinase isoform from Glomas mosseae-inoculated roots of Pisum sativum L.

Colonization of Pisum sativum L. cv. Frisson roots with the arbuscular myco rrhizal fungus Glomus mosseae leads to the induction of four acidic symbios is-related chitinase (SR-chi) isoforms (EC 3.2.1.14). These isoforms were c haracterized as 30-kDa proteins with isoelectric points ranging between 5.2 and 5.85. One of these SR-chis was purified by affinity and anion-exchange chromatographics, and isoelectric focusing electrophoresis. The sequences of four internal peptides were obtained. They showed high homology to a cla ss-1 chitinase isoform from pea shoots. Parts of the conserved regions of c lass-1 chitinases were found in this SR-chi. This result strongly supports the argument that this SR-chi isoform is of plant origin. The functional ro le of the SR-chis in arbuscular mycorrhizal symbiosis is discussed.