RESUMO
Phytophthora austrocedrae is a new species isolated from necrotic lesions of stem and roots of Austrocedrus chilensis. It is a homothallic species characterized by semipapillate sporangia, oogonia with amphigynous antheridia, and very slow growth (1-2 mm d(-1) on V-8 agar at 17.5 degrees C optimum temperature). Phylogenetic analysis of ITS rDNA sequence indicates that its closest relative is Phytophthora syringae, another species frequently isolated from soil and streams in A. chilensis forests.
Assuntos
Phytophthora/classificação , Argentina , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Filogenia , Phytophthora/genética , Phytophthora/isolamento & purificação , Casca de Planta/microbiologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Especificidade da EspécieRESUMO
A survey of Phytophthora spp. in declining and healthy Austrocedrus chilensis forest was conducted to obtain an overview of the species that inhabit these forests. Seventeen declining and three healthy stands plus 11 associated streams were surveyed. Five Phytophthora species were recovered. P. syringae was the most common species isolated from soil and/or streams at nine declining sites and one healthy site. P. gonapodyides was isolated from streams only, at five declining sites. P. cambivora was isolated from soil and the undescribed taxa 'P. taxon Pgchlamydo' and 22 'P taxon Raspberry' were isolated from streams at one declining site each. The species were identified by ITS rDNA sequences and morphological features. Brief descriptions of each species and a discussion of their possible relationship with "mal del ciprés" are presented.