Potencial indutor de resistência de compostos semissintéticos à antracnose do feijoeiro: mecanismos bioquímicos e de ação

Abstract

Among the most important diseases that affect the bean crop is Colletotrichum lindemuthianum (Sacc. & Magn.) Scrib., the causal agent of anthracnose, which causes significant economic damage to producers worldwide. Among the most important factors that contribute to the spread of the pathogen is the use of contaminated seeds. Thus, this study aimed to evaluate biochemical defense responses in seedlings, when seeds were treated with molecules that have antimicrobial potential: Phenyl Se Citronelal and Phenyl S Citral, in three concentrations (g 100 mL-1): 0.25%, 0.50% and 1%, after artificially inoculated with C lindemuthianum in osmotically modified medium. Disease transmission index, total chlorophyll and carotenoid contents, phenolic compounds, lignin derivatives (LATG), antioxidant metabolism, superoxide dismutase (SOD), Catalase, (CAT), ascorbate peroxidase (APX) activity were evaluated. Promising results were obtained, demonstrated by biochemical analysis, mainly in treatments with the Phenyl Se Citronelal molecule, a higher activity compared to the Phenyl S Citral molecule and the respective controls. In the same way, the enzyme activity linked to pathogenicity in vitro was evaluated, using specific solid means, to quantify the production index of amylase, lipase, protease, pectinase, cellulase, low effect of the products Phenyl Se Citronellal and Phenyl S citral in three different concentrations (g 100 ml-1): 0.25%, 0.0625% and 0.125% that do not completely inhibit the growth of the fungus in order to analyze its enzymatic production. Evaluating the presence of degradation halos, which when positive were measured to calculate the Enzyme Index (IE). As for the enzyme production, the isolate C. lindemuthianum, presented performances in four of the five enzymes in study, being the highest activity in the enzymes lipase and protease. It was concluded that the molecules are promising in inducing resistance in bean seedlings when the seeds are treated and in reducing the production of enzymes linked to pathogenicity by the fungus.