Histological and cytological responses of genotypes from Capsicum spp. to Meloidogyne enterolobii

Abstract

Sweet and chilli peppers (Capsicum spp.) are widely cultivated horticultural crops, but they are highly susceptible to root-knot nematodes (Meloidogyne spp.). Among them, Meloidogyne enterolobii stands out for its aggressive parasitism and the severe damage it causes to economically important crops. This study aimed to describe and compare the anatomical and cytological alterations induced by M. enterolobii in the root system of susceptible (Cambuci, UFGCBA 3) and resistant (Bode Roxa A, UFGCCH 24) Capsicum genotypes, either inoculated (I) or non-inoculated (NI), and evaluated at five developmental stages. A completely randomised 2 × 2 × 5 factorial design was used, with assessments at 7, 14, 21, 28, and 35 days after inoculation (DAI). Nematode population density and reproduction factor were quantified, and histological analyses were performed on infected and healthy roots. M. enterolobii successfully penetrated and established in the roots of both genotypes, inducing giant cell formation and pronounced hypertrophy around feeding sites. However, the resistant genotype Bode Roxa A exhibited smaller giant cells accompanied by localised necrosis at 14 and 28 DAI, suggesting a delayed hypersensitive-like reaction. In contrast, enhanced cell proliferation and thickening of parenchymatic tissues were observed at 21 DAI in resistant plants, indicating active cellular reorganisation. These findings underscore the relevance of histopathological and cytometric analyses in understanding plant-nematode interactions and highlight Bode Roxa A as a valuable genetic resource for breeding resistant and sustainable Capsicum cultivars, contributing to crop resilience and food security.