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First Report of Apple chlorotic leafspot virus in Motherstock Nurseries of Stone Fruits in Afghanistan

    Authors and Affiliations
    • S. Rehman
    • J. Ahmad
    • H. Sediqi
    • H. Zahir , Plant Biotechnology Laboratory, Seed and Planting Material Certification Directorate, Ministry of Agriculture, Irrigation and Livestock, Kabul, Afghanistan
    • C. Lanzoni
    • C. Rubies Autonell
    • C. Ratti , DipSA – Plant Pathology, University of Bologna, 40127 Bologna, Italy.

      The services of the Plant Biotechnology Laboratory-Badam Bagh in disease control and management are an essential support to the horticulture sector in Afghanistan. This laboratory started screening the health status of Afghan Germplasm National Collections and mother stock nurseries in order to ensure the production and distribution of virus-free fruit trees. With this purpose, a survey for the detection of Apple chlorotic leafspot virus (ACLSV) was conducted on mother stock nurseries of stone fruits (apricot, peach, plum, and almond) during spring seasons of 2013 to 2015 in Afghanistan. Samples (fresh leaves from a single tree) were collected from 20% of the National Collections’ mother plants, distributed in 22 provinces in six agro-ecological zones of the country. A total of 4,239 samples were analyzed by DAS-ELISA using reagent kits from BIOREBA AG and 23 were found positive for ACLSV. These were two plants of European plum (Clone 364/local name Alu Bokhara Shalili), one plant of Myrobalan and Japanese plum cross (4031/Grangej Zard), 17 plants of peach (five from 804/Turki Sorkh, five from 812/Dir Ras and seven from 811/Turki Zard), one plant of almond (159/Sattarbai Bakhmali), and two plants of apricot (373/Shakarpara and 4037/Aqa Banu). A 677-bp long nucleotide fragment, corresponding to partial coat protein gene, has been amplified from all ELISA-positive samples by RT-PCR using ACLSV sense and antisense primers (Menzel et al. 2002). Sequence analysis revealed similarity ranging from 83.6 to 100% within 11 selected ACLSV Afghan isolates. The similarity varied within the three isolates of each peach accession 812/Dir Ras (89.9 to 99.6%), 811/Turki Zard (88.9 to 99.0%), and 804/Turki Sorkh (83.7 to 89.0%) and the two isolates from the European plum accession 364/Alu Bokhara Shalili (99.6%). BLAST analysis showed that the sequences of two peach isolates 812/Dir Ras (KU749441 and KU749443) shared the highest nucleotide similarity (95.0 and 96.2%) with the GenBank ACLSV isolates Apr 3 from Jordan (AJ586631) and isolates S4, PP23, PP63, and HL2 (JN849008, GU327991, GU328003, and GQ334211) from China. Sequence analysis of 364/Alu Bokhara Shalili (KU749433, KU749434), 804/Turki Sorkh (KU749435), and 811/Turki Zard (KU749439) isolates showed 99.6 to 100.0% identity between each other and shared high (94.3 to 94.7%) nucleotide identity with the Iranian isolate T12Ja (KM586376). Lower nucleotide similarity (86.2%) was observed between the 804/Turki Sorkh isolate KU749437 and the 274-Chal (FN391009) isolate from Greece. Finally, the sequence analysis of isolates 804/Turki Sorkh (KU749436), 811/Turki Zard (KU749438 and KU749440), and 812/Dir Ras (KU749442) revealed a higher degree of identity (86.2 to 88.4%) with the corresponding nucleotide sequences of the isolate SK-92-pl (HQ398253) from Slovakia. To our knowledge, this is the first report of ACLSV occurrence on peach, plum, almond, and apricot plants in Afghanistan. Apparently, our mother stock nurseries are infected by several isolates of the virus. Due to the economic importance of ACLSV in stone fruits, sanitation measures should be adopted to prevent further spread of the virus in Afghanistan.