Abstract

LUJAN-HIDALGO, M. C. et al. Biochemical changes in response to rust attack in coffee plantations. Polibotánica [online]. 2020, n.49, pp.149-160.  Epub June 20, 2020. ISSN 1405-2768.  https://doi.org/10.18387/polibotanica.49.10.

Plants use various mechanisms to defend against pathogenic fungi attack. Some of these mechanisms include the increase of secondary metabolites, antioxidant and hydrolytic enzymes and polysaccharides that cause death or reduce the progression of pathogenic fungi. Hemileia vastatrix (coffee rust) is a biotrofo fungus that causes severe damage to coffee plantations. Occasionally, plants with rust absence of symptoms may be observed in coffee plantations. The study of these asymptomatic plants is of paramount importance for conservation and breeding of resistant germplasm to H. vastatrix. For the study, plants that did not have symptoms during the incidence of the disease were called uninfected (Ni) and those that had them infected (i). Two periods were evaluated: before and during rust infection, in Ni and i plants grown in the field under an organic production system. In this study enzymatic activity of quitinase, β-1-3 glucanase and peroxidase were determined. Additionally, total phenols, chlorogenic (3-CQA), criptochlorogenic (4-CQA), neochlorogenic (5-CQA), pherulic (AF), cafeico (AC), gallic acids and cafeine (Caf) were quantified in infected or non-infected C. arabica plants. No differences (p<0.05) were found in the concentration of 3-CQA and caffeic acid in the i and Ni plants in the two periods evaluated. The concentration of 5-CQA was 5.3 times lower in Ni plants compared to i during rust infection, however, this metabolite was not detected prior to the incidence of rust infection. The concentration of ferulic acid was higher in the Ni before infection, while the content of gallic acid in the i. Chitinase activity was higher in Ni and this activity increased during infection, glucanases was higher in i and peroxidase was higher in Ni in both periods. The results suggest that the resistance of coffee plants to rust disease is related to the presence of phenolic compounds and pathogenesis-related proteins (PR) such as chitinases, glucanases and peroxidase activities.

Keywords : Caffeine; chitinase activity; glucanase activity; peroxidase.

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