Elucidating bioactive compounds and antioxidant enzymes in Coffea arabica for enhanced defense against Meloidogyne paranaensis

Meloidogyne paranaensis (Mpar) is highly aggressive to the coffee tree, causing damage to the root system and, consequently, coffee production. Genetic resistance is the primary environmentally safe measure to manage Mpar. However, there are few studies on the resistance mechanisms in the interaction between coffee and Mpar. This study aimed to identify the bioactive compounds and the enzymatic antioxidant system involved in the resistance of genotypes Guaiçara and 28–4-1 Coffea arabica to Mpar. The bioactive compounds were identified by high-performance liquid chromatography (HPLC Shimadzu®) and the enzymatic antioxidant system by the colorimetric method in a spectrophotometer. 28–4-I was evaluated as rootstock and graft of susceptible cultivar Catuai. The chlorogenic acid (CGA) content was higher in resistant genotypes inoculated with Mpar. The leaves of inoculated plants of the Catuai and Guaiçara cultivars presented an increase in caffeine content and in trigonelline content. Ascorbate peroxidase (APX) activity was higher in the roots of inoculated Guaiçara plants compared to cv Catuai and genotype 28 as the rootstock of Catuai. Superoxide dismutase (SOD) activity increased in the roots of the inoculated plants of the Guaiçara genotype at 14 and 32 DAI and 190 DAI in the leaves of the various graft combinations of genotype 28. The resistance of Guaiçara to Mpar involves the production of the bioactive compounds CGA, caffeine, and trigonelline and increased activity of APX and SOD in the roots. Genotype 28–4-1 indicates that the higher content of CGA and increased APX and SOD activity are involved in the defense response to Mpar. Thus, the exogenous application of CGA should be investigated as a biocompound for protecting Arabica coffee trees against Mpar.