Generation and Retention of Defective RNA3 from Cucumber Mosaic Virus and Relevance of the 2b Protein to Generation of the Subviral RNA

Abstract

A defective RNA3 (D3Yα) of strain Y of cucumber mosaic virus (CMV-Y) was examined on host-specific maintenance, experimental conditions, and a viral factor required for its generation in plants. D3Yα was stably maintained in cucumber but not in tomato plants for 28 days post inoculation (dpi). D3Yα was generated in <i>Nicotiana tabacum</i> or <i>N. benthamiana</i> after prolonged infection in the second and the third passages, but not in plants of <i>N. benthamiana</i> grown at low temperature at 28 dpi or infected with CMV-Y mutant that had the 2b gene deleted. Collectively, we suggest that generation and retention of D3Yα depends on potential host plants and experimental conditions, and that the 2b protein has a role for facilitation of generation of D3Yα.