CHITINASE AND BETA-1,3-GLUCANASE ACTIVITIES IN CHICKPEA (CICER-ARIETINUM) - INDUCTION OF DIFFERENT ISOENZYMES IN RESPONSE TO WOUNDING AND ETHEPHON

Chitinase and beta-1,3-glucanase activities were assayed in roots, ste ms and leaves of 12-day-old chickpea (Cicer arietinum L.) plants. Whil e glucanase activity was higher in roots than in the aerial parts of t he plant, leaves had higher chitinase activity. Both glucanase and chi tinase activities were induced in roots and stems in response to wound ing (excision into 1-cm pieces), with activity increasing 6 h after tr eatment, reaching a maximum between 24 and 48 h, and thereafter remain ing nearly constant up to 72 h. Ethephon treatment also induced beta-1 ,3-glucanase and chitinase activities in stems but not in roots. Both enzymes occurred in root and stem tissues as a complex mixture of isoe nzymes. At least four different peaks with glucanase and chitinase act ivities could be resolved by gel filtration chromatography on Sephacry l S-200 and chromatofocusing on PBE 94 (pH 4-7). Following ammonium su lfate precipitation and ion exchange on CM- and DEAE-Trisacryl, three beta-1,3-glucanase and chitinase fractions, referred to as basic, neut ral and acidic, were separated on the basis of their chromatographic b ehaviour. Most of the total protein (75%) of stem extracts was found i n the acidic fraction, whereas the major glucanase (53%) and chitinase (62%) activities were in the basic and neutral fractions, respectivel y. While wounding resulted in an increase in the neutral glucanase and chitinase activities, the activities of the acidic fractions were pro moted by ethephon.