First Report of Phaeoacremonium inflatipes and Phaeoacremonium mortoniae Associated with Grapevine Petri Disease in Iran.

Petri disease is responsible for grapevine decline and occurs wherever grapevines (Vitis vinifera) are cultivated. Phaeoacremonium species are among the principal hyphomycetes associated with Petri disease. During 2009, a field survey was conducted throughout different vineyards in the Fars province of Iran in order to determine the fungal pathogens associated with the vine decline observed in the region. Samples were taken from grapevines showing yellowing, interveinal chlorosis, leaf necrosis, reduced growth, wilting, wood necrosis and streaking, and xylem discoloration symptoms in cross section. Isolations were made from symptomatic wood tissues from cordons and trunks on malt extract agar supplemented with 1 mg ml-1 streptomycin sulphate (MEAS) and potato dextrose agar (PDA) media. Based on morphological and molecular characteristics two species of Phaeoacremonium, Phaeocremonium mortoniae and Pm. inflatipes, were isolated and identified from grapevines showing yellowing, slow dieback, stunted growth, and reduced foliage in Bavanat (Fars province, south-western Iran). Pathogenicity tests were conducted on rooted grapevine cuttings (cv. Askari) under greenhouse conditions. Based on the results of pathogenicity tests, both tested Phaeoacremonium species were pathogenic and caused significant vascular discoloration in inoculated cuttings four months after inoculation. The fungi were reisolated from the margins of the lesion and healthy tissue, completing Koch's postulates. Based on our knowledge, this is the first report of Pm. mortoniae and Pm. inflatipes causing grapevine Petri disease in Iran. [ABSTRACT FROM AUTHOR]