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POSTERS: New and emerging diseases

Full-length genome sequence of Cotton leafroll dwarf virus infecting cotton in Alabama
Ana Avelar - University of Arizona. Judith Brown- University of Arizona, Roberto Ramos-Sobrinho- University of Arizona, Drew Schrimsher- AGRI-AFC, Kathy Lawrence- Auburn University, Robert Nichols- Cotton Incorporated

During 2017, previously unreported virus-like symptoms were observed in cotton fields in Alabama (AL). High-throughput Illumina RNA sequencing yielded a ~1,300 bp poleroviral fragment that had its closest match with Cotton leafroll dwarf virus (CLRDV), associated with cotton blue disease (CBD) in Africa, Asia, and most recently in Argentina, and Brazil. CLRDV-specific primers confirmed virus presence in symptomatic cotton plants collected from multiple AL locations during 2017-2018. The objective of this study was to validate an apparently full-length CLRDV-like genome sequence determined by Illumina sequencing of a 2018 AL isolate (5,865 bp), by cloning and sequencing a full-length genome for two AL CLRDV isolates representing Barbour and Macon counties in AL. The CLRDV-like genomes share ~95.0 % pairwise nucleotide identity with an isolate of CLRDV from Brazil (HQ827780). The Illumina- and Sanger- DNA derived sequences encode six open reading frames (ORFs). The ORFs 1-5 share 92-100% amino acid (AA) similarity with isolates from South America. The most divergent coding region, ORF0, encodes for a silencing suppressor, sharing 82.4-88.5% AA similarity with CLRDV isolates from South America, indicating that AL isolates represent a previously unreported CLRDV strain, phylogenetically distinct from typical and atypical CBD-associated CLRDV strains.