PECTINASE ACTIVITY IN VESICULAR-ARBUSCULAR MYCORRHIZA DURING COLONIZATION OF LETTUCE

The production of pectinases in lettuce (Lactuca sativa var. Romana) was examined during the root colonization by vesicular-arbuscular mycorrhizal (VAM fungi Glomus mosseae and G. fasciculatum. Pectin esterase activity was higher in VAM inoculated plants. Endo-polymethylgalacturonase activity peaked 60 days after inoculation, whereas polymethylgalacturonase activity peaked at 30 days. Pectin lyase activity in lettuce and maize (Zea mays var. Calderon) peaked at 30 days when inoculated with G. mosseae, but did not appear until 60 days in plants inoculated with G. fasciculatum. No significant differences in endopolygalacturonase, polygalacturonase and pectate lyase activities were observed between VAM and control plants. The possible role of the different pectinases in colonization of plant root by VAM fungi is discussed.