EFFECT OF SYSTEMIC RESISTANCE INDUCTORS ON PR´S ENZYMATIC ACTIVITIES AND SEVERITY OF MANGO ANTHRACNOSE

Abstract

Background: anthracnose (Colletotrichum gloeosporioides) is an important disease in mango (Mangifera indica) due to its worldwide distribution and inducting of severe epidemics in vegetative and reproductive states, causing significant losses. In nature, plants produce defense mechanisms to protect themselves from biotic and abiotic factors by increasing the synthesis of secondary metabolites and enzymes involving processes such as the accumulation of phenolic compounds, β-1, 3-glucanases and chitinases. Objective: in the present work, the increase in the accumulation of phenolic compounds and enzymes related to pathogenesis β-1, 3-glucanases and chitinases was evaluated as a function of inducers of systemic resistance acquired: acibenzolar-S-methyl, salicylic acid and sodium phosphonate (phosphite). Methodology: the applications of treatments were initiated when the plants were approximately 2 years old (6 months of acclimation), the treatments were applied via foliage, the foliage sampling for the enzymatic analysis was performed taken at 0, 5, 10, 20, and 30 days after inoculations (dai) and the variables evaluated were: phenolic compounds concentration, enzymatic activity of β-1,3-glucanasess (GLU) and chitinases (CHI) by chromatographic methods, also the incubation period, incidence, severity were evaluated. Results: analysis of variance, growth dynamics and correlation showed that those treatments where a resistance inducer was applied had significantly lower incidence and severity levels than the control, as well longer incubation periods. The dynamics of phenolic compound concentration and enzymatic activity were similar in all treatments except for control, observing peaks at 5 and 20 days after application. In addition, a significant correlation between the variables: area under the progress curve of the accumulation of phenolic compounds and activity of β-1, 3-glucanases and chitinases with the anthracnose incidence, severity and incubation period could be observed. Implications: in future studies it is recommended to analyze the behavior of treatments in multiple cultivars. Conclusion: these results contribute to the mango agronomic management in the region as precedent in the search to low environmental impact alternatives for diseases management, also contributing to the determination of disease’s etiology.