Replication of an Infectious Form of Tobacco Mosaic Virus in Chicken Embryos

Abstract

PREVIOUS studies^1–3 of the fate of tobacco mosaic virus (TMV) in chicken embryos suggested that the multiplying form was not whole virus. This form was eluted from chicken embryo macerates on cellulose adsorbent columns with 10 per cent polyethylene glycol (PEG) and 4 per cent NaCl in water. Similar infective units could be eluted from infected Turkish tobacco macerates using the same procedure, but whole TMV does not elute in these conditions⁴. The infective material from both chicken embryos and plants, when partially purified, gives an ultraviolet spectrum that is more typical of a nucleoprotein than a nucleic acid. When mechanically inoculated on detached leaves of bean (Phaseolus vulgaris, our selection 367 from P.I. number 223,006) the infective particles induce the formation of small grey lesions. Such lesions appear to be non or only slightly spreading, while whole virus lesions on the same leaves are much larger and spreading, and are dark reddish-brown, in colour. The application of the phenol extraction procedure of Shigematsu et al.⁵ to these infective particles yields a small nucleic acid that still appears to be infective on the bean assay host⁶.