Phylogeny and Pathogenicity of Phytophthora Species Associated with Artichoke Crown and Root Rot and Description of Phytophthora marrasii sp. nov.

Field surveys conducted on nine farms over a 2-year period showed the widespread presence of Phytophthora-related diseases globe artichoke plants in main growing area Sardinia (Italy). Characteristic symptoms included wilting and necrosis outermost leaves dark brown discoloration stem tissues, as well root rot. A total 18 Phytophthora colonies belonging to three species were isolated characterized. Based morphological features ITS sequence data, isolates identified P. crassamura (eight isolates) cactorum (four isolates). Six could not be assigned any formally described are therefore here marrasii sp. nov. The phylogeny places terminal clade basal sister taxa (P. foliorum, hibernalis, lateralis, ramorum) 8c. In particular, is phylogenetically related from which it differs 62 nucleotides region. At same time, can easily distinguished morphologically foliorum mainly because low minimum temperature for growth, bigger persistent non-papillate sporangia, smaller oogonia. Pathogenicity tests confirmed that all pathogenic artichokes, represent new host these pathogens.