Histochemical Root Pathology of Brassica oleracea capitata L. Infected by Pratylenchus penetrans (Cobb) Filipjev and Schuurmans Stekhoyen (Nematoda: Tylenchidae)

J. R. Acedo, R. A. Rohde


Histochemical study of cabbage roots axenically parasitized by Pratylenchus penetrans revealed a five-fold increase in peroxidase activity (localized near lesions), pectic xylem plugs (resembling those caused by Fusarium), and accumulation of oxidase-mediated polyphenols in the region of mechanical injury. Fusarium-resistant cabbage was more susceptible to Pratylenchus than the Fusariunt-susceptible varieties, particularly in the formation of oxidized phenolic compounds. Of 13 fluorescent compounds detected by paper chromatography, one major spot was found to be ferulic acid and a minor one, catechin. Key Words: Pratylenchus penetrans, Lesion nematode, Cabbage, Histochemistry, Pathogenesis, Pectin, Phenolics, Host-parasite relationships.

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