ISHS Acta Horticulturae 550: XVIII International Symposium on Virus and Virus-like Diseases of Temperate Fruit Crops - Top Fruit Diseases
GENOME HETEROGENEITY OF APPLE STEM PITTING VIRUS IN APPLE TREES |
| Authors: | N. Yoshikawa, H. Matsuda, Y. Oda, M. Isogai, T. Takahashi, T. Ito, K. Yoshida |
| Abstract:
The 3’-terminal region of the genomes of four isolates (B39, B12, IG39, and IF38) of Apple stem pitting virus (ASPV) isolated from apple trees was amplified by RT-PCR and the DNA products were cloned and sequenced. The results indicated that isolate B39 comprises at least three sequence variants (SV), isolates B12 and IG39 at least two SV, and these are consistent with the known genome heterogeneity of Apple stem grooving virus in fruit trees (Magome et al., 1997). The nucleotide sequence identities of the coat protein (CP) gene among nine isolates and SV including PA66 reported by Jelkmann (1994) were 64.8 to 89.6 %. Comparison of the amino acid (aa) sequence of CP showed that their aa number varied from 396 to 415 among isolates and SV, and their identities ranged from 69.4 to 92.7 %. The complete nucleotide sequence of isolate IF38 was determined from amplified cDNAs. The IF38 genome consists of 9293 nt excluding the 3’ poly (A) tail, fifteen nt fewer than that of the PA66 genome. Analysis of the putative open reading frames (ORFs) showed that the IF38 genome contains five ORFs in the positive strand, encoding proteins with 247K(ORF1), 25K(ORF2), 13K(ORF3), 8K(ORF4) and 42K(ORF5), respectively. The 42K protein expressed in Escherichia coli reacted with antiserum against ASPV, indicating that the 42K protein is an ASPV-CP. The 3’-noncoding region consists of 132 nucleotides, excluding poly (A) tail, consistent with that of the PA66 genome. The comparison of the nucleotide sequences showed a high variability (76.0 % identity) between the IF38 and PA66 genomes. Comparisons of amino acid sequences of five proteins of IF38 with those of PA66 showed identities of 87.0 % (247K), 94.6 % (25 K), 87.5 % (13 K), 82.9 (8K) and 81.0 % (42 K). The complete nucleotide sequence of ASPV isolate IF38 will appear in the DDBJ, EMBL and GeneBank nucleotide sequence databases with the following accession number AB045371. | |
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