Evaluation of polyphenoloxidase and peroxidase activities and accumulation of phenolic compounds in the resistance of stimulated cassava to Benzo (1,2,3) thiadiazol-7-carbothionic acid-s-methyl ester against Colletotrichum gloeosporioides Penz.

Abstract

Cassava (Manihot esculenta Crantz) is a perennia plant cultivated in the tropical regions of most countries in Africa, Asia and Latin America. It contributes strongly to food security. The aim of this study was to analyze the behavior of polyphenoloxidases (PPO), peroxidase (POX) and phenolic compounds in three cassava varieties during their induction to Benzo (1,2,3) thiadiazol-7-carbothionic acid-s-methyl ester (BTH) against C. gloeosporioides. Resistance induction was evaluated by PPO, POX and total soluble phenolic compounds content accumulated before and after inoculation (I) with C. gloeosporioides, stimulation (St) with BTH and stimulation followed by inoculation (St+I). With the different treatments, there was a progressive and significant (p<0.05) increase in the activity of these enzymes and in the phenol contents in the leaves and stems of the three varieties. These results show that BTH stimulates the defense mechanisms of cassava plants, although these mechanisms differ according to the varieties.