VIEW ARTICLE

Subliminal Infection of Cotton by Tobacco Mosaic Virus. P. C. Cheo, Chief, Research Division, Los Angeles State and County Arboretum, Arcadia, California 91006. Phytopathology 60:41-46. Accepted for publication 11 July 1969. DOI: 10.1094/Phyto-60-41.

Cotton (Gossypium hirsutum) seedlings formerly considered immune to tobacco mosaic virus (TMV) infection were subliminally infected as symptomless carriers. The virus content was approximately 1/200,000th of that produced in a systemic host, Physalis floridana. The inhibition in vitro of TMV by cotton extract was eliminated by high-speed centrifugation. Cotton apparently does not react in a local lesion manner because the total virus content does not vary proportionally to the concentration of the TMV inoculum, even over a difference of 1,000-fold. Furthermore, detached leaf culture under continuous semidarkness or infiltration of infected leaves with tannic acid greatly increases the TMV content in cotton. The stability of TMV infectivity from infected cotton reached a peak about 2 weeks after inoculation, then diminished rapidly.