Sensitive detection of banana bunchy top and faba bean necrotic yellows viruses from infected leaves, in vitro tissue cultures, and viruliferous aphids using polymerase chain reaction

摘要

DNA primers for banana bunchy top virus (BBTV) and for faba bean necrotic yellows virus (FBNYV) were constructed based on the nucleotide sequence of DNA component 1 of each virus that contains the viral putative replicase gene. Three pairs of primers for each virus were utilized for standard polymerase chain reaction (PCR) or immunocapture (IC) PCR amplification. DNA fragments of 439, 446, and 476 bp were amplified from extracts of BBTV-infected banana leaves, in vitro tissue culture, and viruliferous aphids. DNA fragments of 487, 931, and 1002 bp from extracts of FBNYV-infected faba bean plants and viruliferous vectors were also amplified. The amplified DNA fragments were identified by size, nucleotide sequence, and (or) hybridization analysis. Virus-specific DNA fragments were absent from amplified extracts of uninfected banana and faba bean tissues as well as from non-viruliferous aphids. The nucleotide sequence of the PCR-amplified major portion (923 nucleotides) of BBTV DNA component 1 of an Egyptian isolate has been determined. The sequence is 99 homologous to the Australian isolate of BBTV.