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Obtenção in vitro do teleomorfo de Cylindrocarpon destructans, Neonectria Radicicola
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Orientador(es)
Resumo(s)
Black-foot is an important grapevine disease, caused by the fungus Cylindrocarpon destructans, which causes a
darkening of the basal-end of the plant, leading to early decline and death of young grapevines. Both, C.
destructans and C. obtusisporum are considered responsible for this disease, although only the former was
isolated in Portugal. Neonectria radicicola (teleomorph of C. destructans) is an Ascomycota forming perithecia on
host tissue, but such structures haven’t been observed yet in the country in grapevine. There is some
uncertainty concerning the sexual behaviour of the fungus, some authors considering this as a homothallic
species while other considered it as heterothallic. Attempting to obtain the teleomorph of C. destructans, a
collection of 15 isolates was used, originated from different regions of the country. Crosses between isolates
(120 pairs) were done in Petri dishes containing Carnation Leaf Agar (CLA), under Near-UV light (NUV) at
6ºC. For some crosses, perithecia formation began after three months of incubation. After five months of
incubation, morphological and biometrical traits of perithecia, asci and ascospores were evaluated. The
teleomorph was only obtained when crossing distinct isolates, suggesting a tendency for an heterothallic
behaviour of the species. Four isolates can be pointed out as more fertile (Cy68, Cy36, Cy76, Cy111), with Cy68
forming perithecia in 60% of crossings involving it, while the remaining produced perithecia in 33% of crosses.
The identification of these isolates will allow enlarging the scope of the study to all C. destructans isolates
under collection, aiming to confirm the sexual behaviour of this species.
Descrição
Palavras-chave
cylindrocarpon destructans neonectria radicicola pé-negro da videira black-foot of grapevine
Contexto Educativo
Citação
Encontro Nacional de Protecção Integrada, 6º, Castelo Branco, 2003