Enhanced oxidative enzymes activity and lipid peroxidation are associated with hypersensitive response and atypical lesions in resistant bean plants infected with Colletotrichum lindemuthianum

Abstract

This study aimed to investigate the role of oxidative metabolism in resistant (UFSC-01) and susceptible (Uirapuru) bean genotypes against Colletotrichum lindemuthianum (Cl) and its association with phenotypic resistance. Anthracnose severity levels were higher and more varied in susceptible compared to resistant plants. Only UFSC-01 inoculated with Cl exhibited atypical lesions. Cl was detected in symptomatic and asymptomatic tissues of cultivar (cv.) Uirapuru, as well as atypical lesions and asymptomatic tissues of UFSC-01, suggesting that the pathogen can survive and grow without causing any visible symptoms. The activities of guaiacol peroxidase, superoxide dismutase, and ascorbate peroxidase enzymes was significantly higher in Cl-inoculated UFSC-01 compared to the susceptible genotype. There was no change in catalase activity observed in either genotype. After inoculation with Cl, the content of hydrogen peroxide decreased only in cv. Uirapuru, while the amount of malondialdehyde, an indicator of lipidic peroxidation in cells, was found to be higher exclusively in UFSC-01 compared to the other treatments. Our findings suggest that increased enzymes activity and accumulation of molecules involved in oxidative metabolism play a significant role in the defense mechanisms leading to resistance of beans against Cl. These mechanisms can result in cell damage, hypersensitivity response, and atypical lesions in the resistant genotype.