Pepper veinal mottle virus-a new member of the potato virus Y group from peppers (Capsicum annuum L. and C. frutescens L.) in Ghana

Pepper veinal mottle virus (PVMV), a previously undescribed virus widespread in Capsicum annuum and C. frutescens in the Eastern Region of Ghana, is acquired and inoculated in 2 min feeding periods by aphids (Myzus persicae and Aphis gossypii); it is transmissible by inoculation of sap to eleven of fifteen Solanaceae and to five of forty-six other species within three of seventeen other families. The virus was propagated in Nicotiana clevelandii and Petunia hybrida, and assayed in Chenopodium quinoa, C. amaranticolor and C. murale. Sap from Capsicum annuum was infective after dilution to 10^-3 but not 10^-4, after 10 min at 55 but not 60^oC, and after 7 but not 8 days at 25^oC. Lyophilized sap from P. hybrida was infective after 6 years in vacuo. Yields of 10–25 mg of virus per kg of leaf tissue were consistently obtained from P. hybrida or N. clevelandii by extracting systemically infected leaves in 0.5 M borate (pH 7.8) containing 0.2% mercaptoethanol and chloroform, followed by repeated precipitation with 50 g polyethylene glycol (M.W. 6000) per l, several cycles of differential centrifugation and centrifugation in sucrose density-gradient columns. Virus preparations had ultraviolet absorption spectra typical of a nucleoprotein containing c. 6% nuclei acid (A 260/280 = 1.25; A 260/246 = 1.27) and contained numerous unaggregated and unbroken filamentous particles c. 770 times 12 nm which sedimented as a single component with a sedimentation coefficient (s^o_20,w) of 155 S. PVMV contained RNA (moles %: G = 24, A = 23, C = 27, U = 26), and a single protein species with a molecular weight of 32000–33000 daltons. PVMV was not serologically related to potato virus Y (three strains), or to twelve other morphologically similar viruses, and seems to be a distinct member of the potato virus Y group. The cryptogram of PVMV is R/(I):*/(6):E/E:S/Ap.