Induction of systemic acquired resistance associated with the enzyme activity of phenylalanine ammonia-lyase, peroxidase, and polyphenoloxidase and its effect on the severity of anthracnose on nursery mango plants

Abstract

This study evaluated the effect of the consecutive application of chemical resistance inducers on mango anthracnose disease. The study was carried out on mango plants, and we evaluated resistance-inducing treatments: benzothiadiazole (BTH), salicylic acid (SA), and phosphite. Previously characterised C. gloeosporioides and C. asianum strains were used to inoculate the mango plants. We recorded the incubation period, incidence, and severity of the disease and evaluated the enzyme activity of PAL, POD, and PPO. Compared to the inoculated fungal control, the incidence in the units treated with SA and BTH was 50% lower. With phosphite, the number of experimental units with anthracnose decreased by 40%. In units treated with BTH, severity decreased 50%. SA and phosphite decreased severity by 33% and 22%, respectively. The enzyme activity of PAL, POD and PPO significantly increased after treatments. Our results suggest that the increase in enzyme activity contributes to increased resistance to infection by Colletotrichum.