Chitinase and fl-l,3-glucanase activities were assayed in roots, hypocotyls and cotyledons of downy mildewsusceptible and -resistant sunflower (Helianthus annuus L.) cultivars. While the highest fl-1,3-glucanase activity was in roots, that of chitinase activity was in hypocotyls. Inoculation of both sunflower cultivars with Plasmopara halstedii resulted in a marked increase of chitinase and /3-1,3-glucanase activities. The increase was observed earlier in incompatible than in compatible reactions. Both enzymes occurred in root tissue as a complex mixture of isoenzymes. At least three different peaks with chitinase activity and three with glucanase activity could be resolved by gel filtration chromatography on Sephacryl S-100 and chromatofocusing on PBE 94 (pH 7-4). Following ammonium sulfate precipitation and ion-exchange on CM-and DEAE-Trisacryl, three glucanase and chitinase fractions, referred to as basic, neutral and acidic, were separated on the basis of their chromatographic behaviour. A different pattern of distribution of chitinase and fl-1,3-glucanase fractions was observed between inoculated and non-inoculated plants in both resistant (cv. RS-105) and susceptible (cv. Peredovik) cultivars. In healthy plants fl-l,3-glucanase was mainly found in the basic (cv. Peredovik) and neutral (cv. RS-105) fractions, whereas chitinase was in the basic fraction for both cultivars. The neutral and acidic fractions of chitinases were induced in the compatible and incompatible reactions. Inoculation of the plants induced the neutral/3-1,3-glucanase fraction in resistant and susceptible cultivars and the acidic only in the susceptible one. Induction of the basic fraction of both activities was not observed in any case.
Chitinase and β‐1,3‐glucanase activities were assayed in roots, stems and leaves of 12‐day‐old chickpea (Cicer arietinum L.) plants. While glucanase activity was higher in roots than in the aerial parts of the plant, leaves had higher Chitinase activity. Both glucanase and chitinase activities were induced in roots and stems in response to wounding (excision into 1‐cm pieces), with activity increasing 6 h after treatment, reaching a maximum between 24 and 48 h, and thereafter remaining nearly constant up to 72 h. Ethephon treatment also induced β‐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 isoenzymes. At least four different peaks with glucanase and chitinase activities could be resolved by gel filtration chromatography on Sephacryl S‐200 and chromatofocusing on PBE 94 (pH 4–7). Following ammonium sulfate precipitation and ion exchange on CM‐ and DEAE‐Trisacryl, three β‐1,3‐glucanase and chitinase fractions, referred to as basic, neutral and acidic, were separated on the basis of their chromatographic behaviour. Most of the total protein (75%) of stem extracts was found in the acidic fraction, whereas the major glucanase (53%) and chitinase (62%) activities were in the basic and neutral fractions, respectively. While wounding resulted in an increase in the neutral glucanase and chitinase activities, the activities of the acidic fractions were promoted by ethephon.
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