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Molecular Plant Pathology

Molecular Cloning, Sequence Analysis, and Detection of Banana Bunchy Top Virus in Hawaii. W. S. Xie, Department of Plant Pathology, University of Hawaii, Honolulu 96822; J. S. Hu, Department of Plant Pathology, University of Hawaii, Honolulu 96822. Phytopathology 85:339-347. Accepted for publication 9 November 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/Phyto-85-339.

The Hawaiian isolate of banana bunchy top virus (BBTV) was purified from infected banana cultivar Williams. Three single-stranded DNA (ssDNA) components were cloned and sequenced; they were named component 1, 3, and 4, respectively. Component 1 is 1,110 nucleotides in length and shares 98% nucleotide sequence identity with the BBTV DNA component 1 of the Australian isolate. This component contains two open reading frames (ORF) capable of encoding a protein of 33.5 kDa, which may function as a replicase, and a protein about 15.2 kDa, with unknown functions. Component 3 is 1,057 nucleotides in length and does not contain any ORFs larger than 10 kDa. Component 4 is 1,017 nucleotides in length and potentially encodes a protein of 18.9 kDa. All three ssDNA components share the same stem-loop sequence and have a conserved noncoding region. The sequence of each of these three components is different from that of BBTV DNA components of two Taiwanese isolates. BBTV-specific clones were used in dot-blot hybridization assays for detection of BBTV in plants using radioactive and nonradioactive probes. A polymerase chain reaction (PCR) assay was developed for detection of BBTV in banana samples and single aphids. Dot-blot hybridization assays were as sensitive as enzyme-linked immunosorbent assay (ELISA), while PCR was 1,000 times more sensitive than dot-blot and ELISA assays for detection of BBTV in banana.