Characterization PLUM POX VIRUS isolates from different peach varieties in Montenegro

Although Plum pox virus (PPV) is considered the most devastating viral pathogen in stone fruits in Montenegro, data about occurrence of its strains in the most important peach-growing area is scarce. In September and October 2011, chlorotic ringspots, veinal chlorosis, netting, blotches and deformations, were observed at peach trees in the vicinity of Podgorica. In this study, 58 symptomatic leaves samples originated from 8 different varieties (Rita Star, Morsiani, Caldesi, Adriana, Gloria, Spring Belle, May Crest, Spring Crest, Maria Marta) were collected. Presence of PPV was ascertained in 35 samples (60.3%) using Real-Time PCR. The highest PPV infection rate was detected in Maria Marta and Spring Belle (83.3%), followed by Spring Crest (75%), Adriana and May Crest (66.7%), Gloria and Morsiani (62.5%) and Rita Star (55.5%). PPV was not detected in Kaldesi variety. In order to determine molecular variability of PPV isolates, four highly infected samples were selected from four varieties (Maria Marta, Gloria, Morsiani and Rita Star). RT-PCR method with primers targeting CP region, was followed by cloning and sequencing of 1276 bp DNA fragment. Sequence analyses revealed that all peach isolates from Montenegro shared 92.2 – 99.1% nucleotide identity with corresponding PPV-M strain sequences deposited in GenBank. The Montenegrin isolates 374/11 from Rita Star and 399/11 from Gloria were most closely related (99.1 and 97.1%) with isolate SK68 (M92280.1), while isolates 377/11 from Morsiani and 424/11 from Maria Marta shared most identity (97.6 and 98.1%) with previously reported Montenegrin isolate Godinje 1 (HQ452396) from region of Bar. Considering the high percentage of infected trees in the most important peach-growing area, a severe control related to importation and production of virus-free propagation material, as well as an eradication of infected trees is of the great importance in Montenegro.