Elimination of pepper mild mottle virus from infected tobacco (Nicotiana benthamiana L.) plants by callus culture and the sieving technique

摘要

Pepper mild mottle virus (PMMoV) is a positive-sense, single-stranded RNA virus that belongs to the genus Tobamovirus and often causes significant field and greenhouse crop losses worldwide. Typically, PMMoV is transmitted through the seeds and soil (Kim et al. 2005; Jarret et al. 2008). Various methods are currently available for the elimination of viruses from plants, including tissue culture, chemotherapy, and thermotherapy either alone or in combination (Howell et al. 1998; Hosokawa et al. 2004; Sharma et al. 2008). Chemotherapy has been tested for several for its usefulness in virus elimination in combination with meristem culture. However, the technique has met with only limited success and often the role of antiviral compounds in virus suppression or inactivation has been doubtful (Kartha 1986; Cassells 1987). In light of contradictory reports on the effectiveness and phytotoxicity of antiviral compounds (Cassells and Long 1980; Simpkins et al. 1981), chemotherapy has not been generally recognized as an effective method for virus elimination, though recent reports suggest that some antiviral compounds have potential for improving the efficiency of virus elimination when used in combination with meristem and shoot tip culture (Nehra and Kartha 1994). Heat treatment does not eliminate most viruses, but it reduces virus multiplication and translocation in the plant (Roca 1985). Thermotherapy, coupled with shoot tip grafting, has been used to eliminate viruses from kinnow plants (Sharma et al. 2008). High-temperature treatment at 38°C for 70 d was effectively used for the elimination of apple scar skin virus, but this method requires long treatment periods (Howell et al. 1998).