Citrus viroid Ia is a derivative of citrus bent leaf viroid (CVd-Ib) by partial sequence duplications in the right terminal region.
Nucleotide sequences of group I citrus viroids Ia (CVd-Ia) and citrus bent leaf viroid (CBLVd, formerly designated CVd-Ib) isolated from citrus plants in Japan, the Philippines and China have been determined. Citrus samples in Japan and the Philippines contained CVd-Ia, which consists of 328 nucleotides(nt). Although 10 nt longer than the type CBLVd-225A in Israel they share 94% identity in overall nucleotide sequence. The Philippines sample also contained a 329-nt long CVd-Ia sequence variant, in which one base insertion and three substitutions were observed. A citrus in China contained CBLVd, which consists of 318 nt and shares 98% identity to CBLVd-225A. CVd-Ia was clearly separated from CBLVd by two 5-nt insertions located in upper (5'-AGCUG-3') and the lower (5'-CUUCU-3') strand of the right terminal region (which is also designated T2 domain) in rod-like secondary structure. Since both of the additional 5-nt sequences are similar to the adjacent sequences (5'-AGUUG-3' and 5'-CUUCU-3'), we hypothesize that CVd-Ia is a derivative of CBLVd caused by partial sequence duplications and substitutions taking place in the right terminal region.
Hataya
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Department of Agrobiology and Bioresources, Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Nakahara
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Ohara
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Ieki
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Kano
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D001483:Base Sequence; D002957:Citrus / Q000821:virology*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D005784:Gene Amplification; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D014772:Viroids / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
D017931:DNA Primers; D018076:DNA, Complementary; D004279:DNA, Viral; D012367:RNA, Viral