Archivio Journal of Plant Pathology

Abstract:

In June 2013, a survey was conducted for grapevine decline in Abadeh (Fars province, south-western Iran). Branch and trunk samples were collected from grapevines showing Petri disease symptoms, i.e. stunted growth, chlorotic leaves, and necrosis in cross-sectioned wood. Isolations were made from symptomatic wood tissue on malt extract agar (MEA). Six isolates of a Phaeoacremonium sp., were recovered from a 10-year-old grapevine stock (Vitis vinifera cv. Askari). Colonies were flat, pink to beige on MEA, conidiophores were mostly short and unbranched, 16-45 (average 27.5) μm long and type III phialides were predominant. Conidia were hyaline, obovoid or ellipsoidal, 2.5-4.5 (3.4) μm x 1.2-1.4 (1.3) μm. Based on cultural and morphological characters, the isolates were identified as Phaeoacremonium alvesii (Mostert et al., 2006). The identity of two isolates (IRNHM-ALV103 and IRNHM- ALV104) was confirmed by partial sequencing of the β-tubulin gene, using primers T1 and Bt2b. The sequence of these isolates (GenBank accession No. KP322595 and KP322596). showed 99% identity with the compable ones of Phaeoacremonium alvesii available in GenBank (accession No. EU883990). A pathogenicity test under greenhouse conditions was performed on detached shoots of grapevine and the lesion length was measured. All tested isolates were pathogenic and caused wood discolorations (ranging from 26 to 37 mm) four weeks after inoculation. Fungal isolates identical to those used for pathogenicity trials were consistently recovered from inoculated branches, while re-isolations from mock-inoculated branches were negative. This is the first report of the presence of P. alvesii on grapevine in Iran.