OCCURENCE OF APPLE CHLOROTIC LEAF SPOT VIRUS IN APPLE AND QUINCE IN SOUTHERN IRAN
E. Alemzadeh, A.T. Katsiani, K. Efthimiou, N.I. Katis
Apple chlorotic leaf spot virus (ACLSV, genus Trichovirus, family Betaflexiviridae) is a widespread virus that naturally affects pome and stone fruit as well as other Rosaceae species. Recently, the virus has been reported in apple trees in Northern Iran whereas quince and pear were found to be ACLSV-free (Keshavarz and Shams-Bakhsh, 2015). During a survey, conducted from April to September of 2013 in Shiraz area (Southern Iran), leaf samples from two quince trees exhibiting chlorotic leaf spots and fruit deformation and from fifteen symptomless apple trees, were collected. ACLSV presence was ascertained serologically by DAS-ELISA using specific polyclonal antibodies (Dr. T. Candresse, INRA, Bordeaux) and by an ACLSV-specific nested RT-PCR (Katsiani et al., 2014) using the primer pair CLSup and CLSdo (Mathioudakis et al., 2010) targeting close to the 3 ́ end of the coat protein (CP) gene sequence. All 17 tested samples were positive with both methods and direct sequencing of two amplified products (374 bps), one from quince and one from apple, confirmed the identification of ACLSV (accession Nos KP172503 and KP172502, respectively). As no Iranian ACLSV sequences were available in the database, BLAST comparison with ACLSV sequences from other countries retrieved from GenBank disclosed that the herein obtained sequences from apple and quince isolates share the highest identity at the nucleotide level with isolates FN386786 from Greece (94.4%) and AB326228 from Japan (94%), respectively. Nucleotide sequence comparison among the Iranian isolates revealed a 99.4% similarity. ACLSV association with the observed symptoms in quince trees remains to be determined, as the diseased trees were not tested for the presence of other common viruses such as Apple stem pitting virus (ASPV). To our knowledge this is the first report of ACLSV in quince in Iran.