Genome Sequence of Cotton Leafroll Dwarf Virus (CLRDV) Infecting Cotton in Georgia, US

Cotton is one of the economically important crops grown in the Southeast United States. Cotton is the top agricultural commodity in Georgia, with a farm gate value of $901 million, contributing to the state's 6.54% revenue. Cotton leafroll dwarf virus (CLRDV, Genus: Polerovirus; Family: Luteoviridae) is associated with Cotton leafroll dwarf disease (CLRDD). CLRDV is a phloem-limited virus transmitted by cotton aphids in a persistent, circulative, non-propagative manner. Since the first detection from Alabama (AL) in 2018, the virus has been reported from the cotton belt east of Texas (TX). During Fall 2018, cotton plants in several fields in Georgia were observed with symptoms such as leaf curling, reddening, and drooping of leaves, subsequent distortion of leaf growth and shortening of upper internodes and their discoloration to deep green. Initial testing of symptomatic and asymptomatic tissues with primers specific to coat protein and movement protein showed the presence of a virus. The nearly complete genome of an isolate from Seminole county was sequenced and analyzed. The genome of CLRDV sequenced in this study had 5868bp and encoded seven ORFs, as previously reported. It was 95 to 98% identical to the genome of other CLRDV isolates from the United States and South America. The US isolates formed a clade separate from that of the South American isolates in the phylogenetic analysis based on nearly full-length nucleotide sequences. With the availability of a full-length genome, further molecular studies to understand the etiology of the disease will be investigated.