Molecular detection and diversity of Apple chlorotic leaf spot virus (ACLSV) isolates originating from wild, ornamental and cultivated hosts species of the family Rosaceae

Apple chlorotic leaf spot virus (ACLSV) is a typical member of genus Trichovirus, (Flexiviridae) and infects Rosaceae species. In this study 232 samples of ornamental, wild and cultivated plants were collected from several geographical regions of Greece and tested for the presence of ACLSV. Virus detection was based on nested RT-PCR, using primers targeting the coat protein (CP) gene and amplifying a 380 bp product. ACLSV was detected in 77 samples. The highest virus incidence was found in almond (88.9%), followed by peach (63.6%), ornamental plum (57.14%), apple (50%), blackthorn (50%), ornamental quince (42.10%), plum (36%), cherry (32.4%), pear (28.6%), wild cherry (27.3%), almond-leafed pear (21.4%), hawthorn (25%), wild plum (11.1%) and roses (6.2%). The virus was not detected in any of the Sorbus sp. samples tested. Molecular variability was also studied by determining the nucleotide sequence of several ACLSV isolates with primers that amplify part of the CP gene and the 3' untranslated region (UTR). Comparative analysis of the sequences obtained in this study with already published ones showed high molecular variability (76%), which was mainly located in the 3' UTR.