Invasive Species Compendium

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Abstract

First report of clover yellow vein virus in Crotalaria micans in Hawaii.

Abstract

In September 2018, conspicuous virus-like symptoms of chlorotic mosaic and yellowing were observed in a roadside patch of Crotalaria micans on the Big Island (Island of Hawaii), where foliar samples from five individual plants were collected and subjected to molecular and biological characterization. All five samples were found to be bean common mosaic virus (BCMV)-positive using an ELISA test; all five were mechanically inoculated to Nicotiana benthamiana and 2 weeks after inoculation developed clear virus-like symptoms and were confirmed to be BCMV-positive using the ELISA test. To examine samples for possible mixed infections, two original C. micans and one N. benthamiana samples were collected, total RNA was extracted, depleted of ribosomal RNA, and submitted to the high-throughput sequence (HTS) analysis. Three potyviruses were identified among the virus-specific contigs recovered from C. micans: three distinct isolates of BCMV, bean yellow mosaic virus (BYMV), and clover yellow vein virus (ClYVV). All three viruses (BCMV, BYMV, and ClYVV) were detected in the original samples by RT-PCR. The presence of two of the HTS-uncovered viruses in the N. benthamiana samples was confirmed by ELISA tests for BYMV and BCMV. BCMV and ClYVV were biologically separated from this mixed infection in N. benthamiana through a single-lesion selection on Chenopodium quinoa with subsequent back inoculations to N. benthamiana. These BCMV and ClYVV isolates produced distinct symptoms in N. benthamiana: vein clearing for ClYVV and mild mosaic and leaf deformation for BCMV. This is thought to be the first report of ClYVV found in Hawaii, and the first report of BYMV, BCMV, and ClYVV infecting Crotalaria spp.