Phylogenetic data for the description of Phytophthora heterospora sp. nov.

Since 1999, an unusual Phytophthora species has repeatedly been found associated with stem lesions, root and collar rot on young olive trees in Southern Italy. In all cases, this species was obtained from new commercial plantations or from nursery seedlings. Morphologically the Phytophthora isolates were characterized by the abundant production of caducous conidia and sporangia, resembling P. palmivora var. heterocystica. Additional isolates with similar features were obtained from nursery plants of Ziziphus spina-christi in Iran, Juniperus oxycedrus and Capparis spinosa in Italy, and mature trees in commercial farms of Durio zibethinus in Vietnam. In this study, morphology, breeding system and growth characteristics of these unusual Phytophthora isolates were examined, and a combined mitochondrial and nuclear multigene phylogenetic analysis was performed. The proportion between conidia and sporangia varied amongst isolates and depending on the availability of free water. Oogonia with a...