Nematropica (2000) 30, 201-210
A.C.F. de O. Rodrigues, I.M. de O. Abrantes, M.T. Melillo and T. Bleve-Zacheo (2000)
Ultrastructural response of coffee roots to root-knot nematodes, Meloidogyne exigua and M. megadora
Nematropica 30 (2), 201-210
Abstract: Histological and ultrastructural changes induced in Coffea arabica cv. Catuaí amarelo and Catimor (Coffea arabica cv. Caturra x Timor Hybrid) by two populations of Meloidogyne exigua and one of M. megadora are reported. All second-stage juveniles of both species penetrated through the rhizodermis of the root directly behind the root cap and reached the stele near the vascular elements. In Catuaí amarelo roots, cells acting as feeding sites increased their synthetic activity and became multinucleate cells. Nuclear activity and dense cytoplasm observed in cells of roots inoculated with M. exigua indicated a susceptible response of the coffee plants. Seedling cells fed upon by M. megadora showed retraction and roughening of the inner wall surface, great presence of paramural bodies and processes of autophagy within the vacuoles, all suggesting an intermediate response between susceptibility and resistance. In Catimor coffee, all Meloidogyne populations tested induced necrosis of injured root cells. Following minor cytoplasmatic changes, the nurse cells showed condensation of chromatin, altered carbohydrate metabolism, development of lysosomes and autophagic vacuoles. This response seems to be a hypersensitive-like response that leads to cell death six days after nematode infection.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Maria Teresa Melillo, Isabel M. de O. Abrantes, Teresa Bleve-Zacheo
Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
Pest and/or beneficial records:
Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
---|---|---|---|---|
Meloidogyne exigua | Coffee (Coffea) | Nicaragua | ||
Meloidogyne megadora | Coffee (Coffea) | São Tomé and Príncipe |