Authors : Gülten Nisan Ozan, Deniz Çaplık, Harun Bayraktar
DOI : 10.1007/s42161-024-01717-w
Volume : 106
Issue : 4
Year : 2024
Page No : 1875-1876
Türkiye is one of the world’s largest cherry (Prunus avium L.) producers. In August 2022, dieback and canker diseases of cherry trees were detected in an orchard in Çınar district of Diyarbakır (37°41’17.0"N 40°21’19.0"E), Türkiye, with an incidence of 5%. Symptoms included blight and branch canker, dark bark and wood discoloration, and dieback. Wood tissue samples from three trees were superficially disinfected for 1 min in 1% NaOCl and transferred to Petri dishes containing potato dextrose agar (PDA). Colonies were initially white but later became yellow to brown. Verticillate branched conidiophores with phialides arranged in divergent whorls were observed. Conidia formed as chains on phialides were one-cell, ellipsoidal to cylindrical in shape with truncate ends, measuring 2.85–5.11×2.10– 3.00 μm. Chlamydospores were globose, smooth-walled, and 3.20 μm in diameter. These characteristics are consistent with those reported previously for Paecilomyces maximus (syn. Paecilomyces formosus) (Houbraken et al. 2020). To confirm identifications, the internal transcribed spacer region of rDNA (ITS) and the β-tubulin gene for a representative isolate were sequenced (White et al. 1990; Glass and Donaldson 1995) and deposited in GenBank (Accession Nos. ITS: OR744819 and β-tubulin: OR757268). The sequences exhibited 99.6% similarity for ITS (FJ389927) and 100% similarity for β-tubulin (FJ389983) sequences of strain CBS 628.66 of P. maximus. Phylogenetic analysis confirmed the identification. Koch’s postulates were completed by inoculating six 35 cm branch segments, wounding them with a 5 mm cork borer, and inserting a 5 mm mycelial agar plug from a 15-day-old culture. Sterile agar plugs were used as controls. Inoculated branches were incubated in moist chamber at 24 °C for five weeks. Brown necrotic lesions were observed on inoculated branches, but no symptoms were observed on control branches. The same fungus was re-isolated from inoculated tissues to confirm Koch’s postulates. To our knowledge, this is the first report of P. maximus causing dieback and canker disease of cherry in Türkiye.