Antifungal Hydrolases in Pea Tissue

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Abstract
Chitinase and .beta.-1,-3-glucanase activities increased coordinately in peak (Pisum sativum L. cv "Dot") pods during development and maturation and when immature pea pods were inoculated with compatible or incompatible strains of Fusarium solani or wounded or treated with chitosan or ethylene. Up to five major soluble, basic proteins accumulated in stressed immature pods and in naturing untreated pods. After separation of these proteins by chromatofocusing, an enzymic function could be assigned to four of them: two were chitinases and two were .beta.-1,3-glucanases. The different molecular forms of chitinase and .beta.-1,2-glucanase were differentially regulated. Chitinase Ch1 (mol wt 33,100) and .beta.-1,3 glucanase G2 (mol wt 34,300) were strongly induced in immature tissue in response to the various stresses, while chitinase Ch2 (mol wt 36,200) and .beta.-1,3-glucanase G1 (mol wt 33,500) accumulated during the course of maturation. With a simple, three-step procedure, both chitinases and both .beta.-1,3-glucanases were purified to homogeneity from the same extract. The two chitinases were endochitinases. They differed in their pH optimum, in specific activity, in the pattern of products formed from [3H]chitin, as well as in their relative lysozyme activity. Similarly, the two .beta.-1,3-glucanases were endoglucanases that showed differences in their pH optimum, specific activity, and pattern of products released from laminarin.