Detection of each of the causal agents of groundnut rosette disease in plants and vector aphids by RT-PCR

Detection of the three agents of groundnut rosette disease (groundnut roset te assistor virus, groundnut rosette virus and its satellite RNA) in plants and vector aphids by reverse transcription-polymerase chain reaction (RT-P CR) is reported. Three procedures for extraction of total RNA from groundnu t were tested, of which two were Found to be useful in giving RNA of suffic ient quality for RT-PCR. Of these two, the total RNA extraction kit supplie d by Qiagen was found to be the most versatile for extraction of all three agents from individual vector aphids (Aphis cracccivora). Both groundnut ro sette assistor virus and groundnut rosette virus could be detected from tot al RNA extracted from a single aphid that had been exposed to either green or chlorotic rosette-infected groundnut plants. They could be detected in a phids stored in 70% ethanol for up to 30 days at room temperature. However, satellite RNA could be amplified only when total RNA extracted from two or more aphids was used. Groundnut rosette assistor virus, groundnut rosette virus and its satellite RNA were detected by RT-PCR in aphids that had been exposed only to groundnut rosette diseased plants containing all three age nts. The potential of RT-PCR in studying certain key issues of rosette dise ase epidemiology is discussed. (C) 1998 Elsevier Science B.V. All rights re served.