First Report of Apium virus Y in Celery in New Zealand

Abstract

Apium virus Y (ApVY) has been detected for the first time in New Zealand. In January 2006, leaf mosaic and vein-banding symptoms were observed on cultivated celery (Apium graveolens cv. Tongo) in Wanganui, New Zealand. Symptoms were widespread and seen in several paddocks. Similar symptoms were also observed in poison hemlock (Conium maculatum), a weed commonly found growing along the edges of the crop. Chenopodium amaranticolor and C. quinoa plants inoculated with leaf sap from a single, symptomatic celery or hemlock plant developed necrotic local spots after 9 and 12 days, respectively. Six Nicotiana spp. did not develop symptoms and were not tested further. Electron microscopy of sap from the celery, hemlock, and C. quinoa plants revealed the presence of elongated flexuous virus particles, 650 to 850 nm long. Symptomatic plants of these three species were tested for ApVY by reverse transcription (RT)-PCR using novel forward (5'-ATGATGCGTGGTTTGAAGG-3') and reverse (5'-CTTGGTGCGTGAGTTCTTG-3') primers specific to the coat protein gene (GenBank Accession No. AF203529). Amplicons of the expected size (approximately 425 bp) were obtained from all samples, and an amplicon from celery was sequenced (GenBank Accession No. EU127499). Comparison with ApVY sequences in GenBank confirmed the identity of the product, which had 97 to 99% nucleotide identity with GenBank Accession Nos. AF 203529, AF207594, and AY049716. The effect of ApVY on celery is unknown. ApVY has recently been described and infects three species of Apiaceae in Australia (2). In this study, diseased celery, but not the hemlock plants, were found to be coinfected with Celery mosaic virus (CeMV) by enzyme-linked immunsorbent assays with CeMV-specific antibodies (Loewe Biochemica GmbH, Sauerlach, Germany). Therefore, the symptoms observed in celery may be induced by ApVY or CeMV. CeMV is a serious disease of celery in New Zealand (1) and CeMV symptoms may mask the presence of ApVY.