First Report of Bougainvillea spectabilis chlorotic vein-banding virus Infecting Bougainvillea Plants in Taiwan.

Bougainvillea (Bougainvillea spectabilis), native to Amazonian rainforests in South America, is an important ornamental and landscaping plant that is widely distributed in tropical and subtropical areas. A new virus disease, Bougainvillea chlorotic vein-banding, caused by a Badnavirus, Bougainvillea spectabilis chlorotic vein-banding virus (BsCVBV), was first reported in Brazil in 2001 (1) and recently discovered in Taiwan. Infected bougainvillea developed symptoms such as mottling, chlorosis, vein-banding, and stunting. Severe leaf-distortion symptoms were observed in the susceptible hybrid Taipei Red, the most popular bougainvillea cultivar in Taiwan. In electron microscopic observations, typical bacilliform virions measuring 28 × 130 to 150 nm were observed in infected bougainvillea cells. In addition, our transmission tests demonstrated that the virus could be easily transmitted among different bougainvillea cultivars by bud grafting but not by mechanical inoculation. Bougainvillea plants showed apparent symptoms 1 month after grafting. For molecular identification, viral DNA was extracted from the test plants (2), and polymerase chain reaction (PCR) was performed using the primers selected from the DNA sequences of ORF III of Sugarcane bacilliform virus (GenBank Accession No. M89923). The sequence of the forward primer was 5'-TCA AAG TTT GAT TTG AAG AGC GGG-3' and the sequence of the reverse primer was 5'-CTT GCA TAC TGC TCC CCA TCC-3' The primers amplified a 676-bp PCR product (GenBank Accession No. DQ103759). Nucleotide and deduced amino acid sequences were 82 and 90% identical, respectively, to the corresponding region of the Brazilian strain of BsCVBV (GenBank Accession No. AY532653). These data indicate that the bougainvillea disease occurring in Taiwan is caused by a strain of BsCVBV. Reference: (1) C. M. Chagas et al. Virus Rev. Res. 6:153, 2001. (2) H.-J. Su et al. J. Phytopathol. 151:290, 2003.