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Physiology and Biochemistry

Time-Course Studies on Virus Titer and DNA Component Ratio in Beans Infected with Bean Golden Mosaic Virus. Teresa L. Shock, Assistant plant pathologist (virology), Department of Plant Pathology and International Soybean Program (INTSOY), University of Illinois, Urbana 61801; Robert M. Goodman, associate professor, Department of Plant Pathology and International Soybean Program (INTSOY), University of Illinois, Urbana 61801. Phytopathology 71:80-82. Accepted for publication 13 June 1980. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-80.

Systemically infected trifoliolate leaves of beans (Phaseolus vulgaris L. ‘Top Crop’) harvested at varying times after sap inoculation of primary leaves with bean golden mosaic virus (BGMV) yielded a maximum titer of 8 μg virus per gram (fresh weight) of tissue. The concentration of virus increased from the time when leaves were just beginning to develop symptoms (5–6 days after inoculation) to a peak (8–12 days after inoculation) and then decreased rapidly. Virus titer in older leaves (> 3 wk after inoculation) with well developed symptoms was very low. The relative amounts of the two topological forms (linear and circular) of DNA present in BGMV were measured during the course of infection. The ratios obtained were between 1:3 and 1:5 (linear:circular). No variation was observed in this ratio with time of harvest after inoculation or with age of infected tissue.