Development of a protocol for the elimination of Cyrtanthus elatus virus-A from Narcissus tazetta by in vitro chemotherapy in combination with electrotherapy.

ABSTRACT

Narcissus (Narcissus tazetta) is a bulbous ornamental plant propagated vegetatively from bulbs. The Cyrtanthus elatus virus-A (CyEV-A) had been reported to cause a severe mosaic and yellow stripe disease in narcissus. Therefore, this study aimed to develop a protocol for the elimination of CyEV-A from infected bulblets by in vitro chemotherapy (30-50 mg/L ribavirin for 30 days) and electrotherapy (10-30 mA for 20 min), individually and in combination, to produce virus-free plants. The regenerated plants obtained from these treatments were screened for the absence of the CyEV-A by reverse-transcription polymerase chain reaction assays using a set of degenerate primers specific for a potyvirus coat protein gene. The results showed that in vitro chemotherapy (30 mg/L ribavirin for 30 days) alone produced 46.0 % (14/30) of virus-free plants, while electrotherapy (20 mA for 20 min) alone produced 40.0 % (12/30) of virus-free plants. In comparison, a combination of chemotherapy (30 mg/L ribavirin for 30 days) and electrotherapy (20 mA for 20 min) produced 50.0 % (15/30) of virus-free plants. The virus-free plants obtained from this combination treatment exhibited better growth and produced more bulbs compared to the other treatments and control. The protocol may be used for the control of the virus disease in narcissus.