Detection of Banana bunchy top virus and Banana streak Mysore virus by PCR: impact of storing virus infected banana samples

Abstract

Banana bunchy top virus (BBTV) and Banana streak Mysore virus (BSMyV) are economically important DNA viruses infecting of banana in India. A study was conducted to evaluate different methods of storage for BBTV and BSMyV infected banana leaf samples for detection by PCR. Virus infected leaves were stored at room temperature (28°C±2) as dried samples, which were processed by three methods viz., hot air oven at 55°C, calcium chloride (CaCl2), and air drying (28±2°C), at 4°C (in refrigerator) and at -86°C (in deep freezer) as wet samples. BBTV was detected in all samples stored at all conditions up to 15th day of storage. On 30th day of storage, the virus was consistently detected in samples dried in hot air oven and desiccated using CaCl2 but not in samples dried at room temperature BSMyV was detected in symptomatic leaf samples dried in hot air oven and CaCl2 desiccation on 45th day of storage and even up to 60th day of storage for samples stored at 4°C and -86°C. In case of asymptomatic samples, the virus was detected on 30th day of storage for samples desiccated with CaCl2 and at 4°C and -86°C. Drying the samples by CaCl2 desiccation improved the detection of banana viruses by PCR. It is recommended that the tissue culture industries can dry the banana leaf samples by CaCl2 desiccation before dispatching to accredited laboratories for testing BBTV and BSMyV.