PRODUCTION OF A POLYGALACTURONASE COMPLEX BY BOTRYODIPLODIA-THEOBROMAE AND ITS INVOLVEMENT IN THE ROT OF SWEET-POTATO

Botryodiplodia theobromae (sweet potato isolate) produced four polygalacturonase isoenzymes, PG 1, 2, 3 and 4, in liquid culture. PG2, 3 and 4 macerated and killed tissue discs of sweet potato and potato tubers, but PGl did not. PG3 was recovered from extracts of sweet potato rotted by B. theobromae. PG activity was highest at the advancing edge of the lesion, less at the unrotted periphery and still less at the centre (oldest part) on the lesion. Total phenol content was highest at the periphery of the lesion and progressively decreased towards the centre of the lesion. Both phenol oxidase and peroxidase were distributed in the same pattern as the total phenols. Activity of rot extract PG was increased six-fold when extraction was done in the presence of an anti-oxidant. © 1979.