Journal of Taiwan Agricultural Research

Author:Yi-Ting Lin, Jye-Yann Liao, Chin-Hui Tsai, and Ting-Chin Deng*

Abstract:

    The nucleotides of genomic RNA2 of Cucurbit chlorotic yellows virus (CCYV) isolates CCYV-Erlun (JN126045) and CCYV-Yilan (JN126046) collected from Taiwan were com-pletely sequenced.  In addition to 5’- and 3’- terminal untranslated regions, a total of 8041 bp in length encoding genes of p4.9 (132 nt), HSP70h (1671 nt), p6 (165 nt), p59 (1554 nt), p9 (240 nt), CP (753 nt), CPm (1425 nt), and p26 (642 nt) were determined by reverse transcrip-tion polymerase chain reaction (RT-PCR) and rapid amplificationof 5' complementary DNA ends (5’-RACE).  The CP gene-targeted primers for RT-PCR would be useful for improving the sensitivity and accuracy of CCYV detection.  Comparative analyses of the nucleotide se-quences of CCYV isolates with those of various geographic origins including Japan, Taiwan, China, and Sudan revealed that the identities are as high as 99% to 100% in respective genes of HSP70h, CP, CPm and entire RNA2.  Entropy plotting demonstrated the variability of nucleotide sequences among two Taiwan isolates and an initial Japan isolate had only 12 di-vergent nt in a total of 8041 nt of RNA2, and the nucleotide sequence variance located mainly in the 5’- and 3’- terminal regions.  The remarkable homogeneity and very close cluster of all CCYV nucleotide sequences available for the phylogenetic analyses indicate that all the cur-rently existing CCYV isolates in the world were originated from the same source.

Key words:CCYV, RT-PCR, Phylogenetic analysis, Entropy plot

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