FIRST REPORT OF CITRUS YELLOW VEIN CLEARING VIRUS INFECTING NEW NATURAL HOST PLANTS IN TURKEY

Abstract

In 2003, Citrus yellow vein clearing virus (CYVCV, genus Mandarivirus, family Alphaflexiviridae) (Loconsole et al., 2012) symptoms were observed in citrus lemon (Citrus limon), sour orange (C. aurantium), sweet orange (C. sinensis), mandarin (C. reticulata) and grapefruits (C. paradisi) in a collection orchard in the Cukurova region in Turkey (Onelge et al., 2011). Here we report on a two-year survey for CYVCV in the collection orchard in spring and autumn. 200 symptomless weed samples of the families Amaranthaceae, Asteraceae, Brassicaceae, Chenopodiaceae, Compositeae, Graminaceae and Solanaceae were analyzed by RT-PCR with a specific primer pair (sense: 5′-ACCTCACCGA TGGACCACGTT-3′ and antisense: CAGAAAATGGAAACTGAAAGCCTG-3′) designed in the coat protein gene (GenBank accession No. JX040635) (Loconsole et al., 2012) and total RNA extracted using the Axigen kit. A 476-bp long amplicon was obtained for three samples of Malva sylvestris, three samples of Solanum nigrum, two samples of Sinapis arvensis and two samples of Rananculus arvensis. All samples were cloned with TA Cloning kit (Invitrogen) and sequenced. BLAST analysis of all amplicons showed more than 97% identity of CYVCV isolates from weeds (Accession Nos. JX040635 and KP313241) with the corresponding region of CYVCV reference genome (Loconsole et al., 2012; Chen et al., 2014). Mechanical transmission of CYVCV from infected weeds to sour orange showed yellow vein clearing on lateral veins, leaf crinkling and deformation on young leaves of indicator plants. The presence of CYVCV was confirmed in the symptomatic sour orange plants by RT-PCR. To our knowledge this is the first report of Malva sylvestris, Solanum nigrum, Sinapis arvensis and Rananculus arvensis as hosts of CYVCV.