Non-destructive DNA extraction from aphids: the application in virus - vector studies of Banana bunchy top virus (BBTV)

Banana bunchy top virus (BBTV), one of the most devastating viruses of banana, is transmitted by the banana aphid, Pentalonia nigronervosa. The high degree of morphological similarity between P. nigronervosa and the related experimental vector P. caladii makes it difficult to distinguish the two species. DNA barcoding can be used as an alternative for the rapid identification of these aphid species. However, standard molecular identification techniques for small insects usually require maceration of the sample to obtain sufficient amounts of DNA, resulting in the loss of voucher specimens. In this study, a non-destructive DNA extraction method for aphids was optimised, allowing the specimens to remain intact for use as vouchers for further morphological studies. Sufficient DNA concentrations were obtained from the aphid extractions and were used for species identification through direct sequencing of PCR products. Extracted DNA was further used to detect BBTV in the insect vector, P. nigronervosa. Approximately 78% of the aphids collected from symptomatic plants in infected plantations in KwaZulu-Natal tested positive for BBTV, as well as some aphids collected in other African countries. The BBTV viral strain identified from South Africa grouped with the “South Pacific” clade. This non-destructive DNA extraction method can be used in an early detection management strategy, especially in epidemiology and virus-vector studies of Banana bunchy top disease (BBTD).