Identification of Colletotrichum acutatum from nectarine fruit

Abstract

Isolates of Colletotrichum spp. obtained from nectarine fruits with typical anthracnose symptoms in 2010 were identified using morphological and molecular methods. Pathogenicity test was conducted on symptomless, detached nectarine fruits. All tested isolates caused anthracnose lesions on nectarine fruits after 7 days of incubation. On PDA medium nectarine isolates forming dark green to dark gray mycelia. Growth rates of all isolates and reference strain of C.acutatum were lower at 25°C compared with reference strain of C.gloeosporioides. The conidia were hyaline, aseptate, and fusiform. Appressoria were dark brown, smooth, simple, and clavate to ovate. Using the primer set CaInt2/ITS4, the 490 bp DNA fragment was amplified from all nectarine isolates and reference strain of C. acutatum - CBS 294.67. Based on these results, the causal agent of anthracnose on nectarine fruits in Serbia was identified as C.acutatum.

Izolati Colletotrichum spp. dobijeni 2010. godine, sa antraknoznih plodova nektarine identifikovani su pomoću morfoloških i molekularnih metoda. Test patogenosti je obavljen sa reprezentativnim izolatima, na odabranim, zdravim plodovima. Svi ispitivani izolati prouzrokuju antraknozne lezije na plodu nektarine, 7 dana nakon inokulacije. Na PDA podlozi izolati formiraju tamno zelenu do tamno sivu miceliju. Stopa rasta izolata sa nektarine i referentnog soja C.acutatum je bila niža u odnosu na referentni soj C.gloeosporioides. Konidije su hialinske, neseptirane i fusiformne. Apresorije su tamno braon boje, glatke, jednostavne, okruglastog ili oblika izdužene palice. Korišćenjem para prajmera CaInt2/ITS4 iz genoma DNA izolata sa ploda nektarine i referentnog soja C. acutatum - CBS 294.67, amplifikovan je fragment veličine 490 bp. Na osnovu ovih rezultata, u Srbiji je kao prouzrokovač antrakoze plodova nektarine identifikovana vrsta C.acutatum.