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Preinoculation with Tobacco Necrosis Virus Enhances Peroxidase Activity and Lignification in Cucumber, as a Resistance Response to Sphaerotheca fuliginea
Author(s) -
Conti G. G.,
Bassi M.,
Carminucci D.,
Gatti L.,
Bocci A. M.
Publication year - 1990
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1990.tb04265.x
Subject(s) - sphaerotheca , biology , inoculation , cotyledon , cucurbitaceae , botany , peroxidase , germination , horticulture , powdery mildew , enzyme , biochemistry
Cucumber plants were mechanically inoculated with TNV and challenge‐inoculated after 7 days with Sphaerotheca fuliginea. The development of the fungus was followed by light microscopy and the modifications of the host leaf cells were studied by histochemical and cytochemical reactions. Conidial germination was similar in control and TNV‐infected plants, and in the following 2 or 3 days S. fuliginea development was also similar. Thereafter in control plants S. fuliginea development progressed steadily and no modifications appeared in the leaf host cells, while in TNV‐infected plants strongly autofluorescing papillae were formed, and peroxidase activity was detected in the walls of many epidermal cells of the challenge‐inoculated, leaf. Lignification ensued, and fungal growth was strongly inhibited. Protection was obtained provided the number of necrotic lesions was at least 12 per cotyledon, and was elicited even if the TNV‐infected leaf was removed 7 days after infection, before challenge inoculation. No protection was induced when the TNV‐infected leaf was removed 3 days after infection.