01979nas a2200181   4500008004100000022001400041245011000055210006900165300001600234490000800250520136300258653002501621100002201646700001701668700002001685700002101705856007101726       2006                        eng d  a0953-756200aStromata, sporangiomata and chlamydosori of Phytophthora ramorum on inoculated Mediterranean woody plants0 aStromata sporangiomata and chlamydosori of Phytophthora ramorum   a1323 - 13320 v1103 a<p>Three types of multihyphal structures, stromata, sporangiomata and chlamydosori, are described for the plant pathogen <em>Phytophthora ramorum</em>. Their morphology, morphogenesis and position on the host organ were observed by dissecting, compound and scanning electron microscopy. Stromata were consistently formed one to two weeks after zoospore inoculation of detached leaves and fruits of an assortment of Mediterranean sclerophyll shrubs. Stroma initials appeared subcuticularly or subepidermally and developed as small hyphal aggregates by repeated branching, budding, swelling and interweaving, eventually forming a prosenchyma. They always emerged through the adaxial side of the leaf by rupture of the overlying host tissue. Occasionally sporangia and chlamydosori (packed clusters of chlamydospores) were formed on the stromata. Sporangiomata bore short sporangiophores and clusters of 20-100 sporangia and resembled sporodochia of the mitosporic fungi. The biological significance of these multihyphal structures is discussed. Some epidemiological aspects were also studied: several understorey species of the holm oak (<em>Quercus ilex</em>) woodland were susceptible to in vitro infection with three isolates of <em>P. ramorum</em> originally collected from different ornamental hosts. The risk of spread to this ecosystem is evaluated.</p>10aSporangial dispersal1 aMoralejo, Eduardo1 aPuig, Miquel1 aGarcia, Jose, A1 aDescals, Enrique  uhttp://www.sciencedirect.com/science/article/pii/S0953756206002656