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Initial molecular characterization of a novel emaravirus from Callicarpa (beautyberry) identified by high-throughput sequencing

Ramon Jordan: USDA-ARS, USNA, Floral & Nursery Plants Research

<div>The genus <em>Callicarpa</em> (beautyberry) contains approximately 140 species of perennial deciduous shrubs and small trees. The common name refers to its most well-known ornamental feature - prolific white, lilac, lavender, or purple-colored fruit that covers the shrub in late summer through autumn. Mosaic symptoms were observed on a <em>Callicarpa americana</em> plant growing in Auburn, AL. Total RNA was purified from leaves of this plant, and a custom cDNA library was prepared for paired-end Illumina MiSeq next-generation sequencing (NGS). Raw sequence reads (3,804,206 35-250bp reads) were trimmed of adaptor linkers and <em>de novo</em> assembled into 197,416 contiguous sequences using Geneious Pro R9. Contig sequences were subjected to BLASTX analysis against known viral sequences in GenBank (NCBI) databases and 15 contigs were identified that had significant putative protein homologies with members of the genus <em>Emaravirus</em>. Complete or near-complete sequences were obtained for genomic RNAs 1-4. The <em>in silico</em> translated proteins have 29-62% amino acid identities with emaravirus orthologs RdRp (RNA 1), glycoprotein precursor (RNA 2), NP (RNA 3), and MP (RNA 4). Results of ongoing NGS and RT-PCR analysis (using <em>Callicarpa</em> emaravirus-specific primers) with other <em>Callicarpa</em> samples will also be presented. Previously, the only virus reported to infect beautyberry was <em>Cucumber mosaic virus</em>. To our knowledge, this is the first report of an emaravirus infecting <em>Callicarpa</em>.</div>