Identification of Acremonium isolates from grapevines and evaluation of their antagonism towards Plasmopara viticola

Some endophytic fungal genera in Vitis vinifera,including Acremonium, have been reported as antagonists ofPlasmopara viticola. Endophytic Acremonium isolates froman asymptomatic grapevine cultivar Inzolia from Italy wereidentified by morphological features and multigene phylogeniesof ITS, 18S and 28S genes, and their intra-specific genomicdiversity was analyzed by RAPD analysis. Culture filtrates(CFs) obtained from Acremonium isolates were testedin vitro for their inhibitory activity against the P. viticolasporangia germination. Among 94 isolates, 68 belonged tothe Acremonium persicinum and 26 to the Acremoniumsclerotigenum. RAPD analysis grouped the A. persicinum isolatesinto 15 clusters and defined 31 different strains. TheA. sclerotigenum isolates, instead, were clustered into 22groups and represented 25 strains. All A. persicinum CFsinhibited sporangia germination of P. viticola, while not allthose of A. sclerotigenum had inhibitory effect. A differentdegree of inhibition was observed between strains of the samespecies, while some strains of different species showed identicalinhibitory effect. No correlation was found betweenRAPD groups and inhibitory activity in both Acremonium