Immunological evidence that .BETA.-1,3-endoglucanase is the major elicitor-releasing factor in soybean.

Abstract

β-1, 3-Endoglucanase highly purified from soybean cotyledon tissue possessed the activity to release soluble elicitors from insoluble cell walls of Phytophthora megasperma f. sp. glycinea. Antiserum raised against the purified enzyme appeared to be specific for soybean β-1, 3-endoglucanase, since it formed a single precipitation band with soybean tissue homogenates in Ouchterlony double diffusion plates but did not react with homogenates of other plant species. The antiserum almost completely inhibited both β-1, 3-glucanase and elicitor-releasing activity by the purified enzyme as well as crude extracts from soybean tissues. Furthermore, these two activities shown by cut soybean cotyledon tissue were also inhibited by the antiserum. The antiserum, however, did not inhibit either β-1, 3-glucanase or elicitor-releasing activity shown by extracts from other plant species. Zymolyase 100T, a partially purified β-1, 3-endoglucanase preparation of bacterial origin, also possessed elicitor-releasing activity. These results confirm the previous observation that elicitor-releasing activity is due to β-1, 3-endoglucanase activity and that β-1, 3-endoglucanase is the major elicitor-releasing factor present in soybean tissues.