First Report of Cucumber mosaic virus Infecting Blephilia hirsuta in North America.

Blephilia hirsuta (Pursh) Benth. var. hirsuta, an ornamental plant known as hairy pagoda or hairy wood mint (Lamiaceae), is native to eastern North America and is listed as an endangered species or a species of special concern in several northeastern states ( http://www.ct.gov/dep/cwp/view.asp?a=2702&q=323482&depNav_GID=1628 and http://www.mass.gov/dfwele/dfw/nhesp/species_info/mesa_list/mesa_list.htm ). B. hirsuta, grown as an ornamental on the University of Arkansas campus in Fayetteville, exhibited mottling symptoms indicative of viral infection. Double-stranded RNA extractions (3) yielded four bands of approximately 3.2, 2.9, 2.2, and 0.9 kb, a pattern identical to that of Cucumber mosaic virus (CMV [2]). Nicotiana benthamiana and Chenopodium quinoa seedlings were mechanically inoculated with sap from symptomatic tissue. N. benthamiana inoculated plants were stunted and developed systemic mosaic and C. quinoa inoculated plants developed local lesions, whereas mock inoculated plants remained symptomless. Dot-blot and indirect ELISA using antisera against CMV (developed by H. A Scott) gave strong reactions when testing symptomatic tissue from B. hirusta, N. benthamiana, and C. quinoa compared with no reaction for symptomless plants. Total nucleic acid extractions (4) from symptomatic tissue was subjected to reverse transcription-PCR using Cucumovirus degenerate primers (1). An amplicon of approximately 940 bases was obtained and sequenced. The sequence, deposited in GenBank under Accession No. GU453918, confirmed the results of the immunological assays that B. hirsuta was infected with CMV. The nucleotide identities between the B. hirsuta isolate and those of the Fny CMV group exceeded 98%. To our knowledge, this is the first report of CMV infecting B. hirsuta, not only in North America, but globally. This finding has major implications for the ornamental industry and the viability of the endangered species. Given the wide range of CMV, B. hirsuta may act as a reservoir for the virus and facilitate transmission to ornamentals and other plants. In addition, the virus may reduce host fitness and undermine the efforts to preserve the species in areas that is threatened. References: (1) S. K. Choi et al. J. Virol. Methods 83:67, 1999. (2) I. E. Tzanetakis. Plant Dis. 93:431, 2009. (3) I. E. Tzanetakis and R. R. Martin. J. Virol. Methods 149:167, 2008. (4) I. E. Tzanetakis et al. Virus Res. 127:26, 2007.