Nucleotide sequence of a circular single-stranded DNA associated with coconut foliar decay virus.

A circular single-stranded (ss) covalently closed (ccc) DNA associated with coconut foliar decay virus (CFDV) was purified, amplified by the polymerase chain reaction, and subcloned and its sequence established by analysis of overlapping subgenomic cDNA clones. The complete CFDV sequence comprised 1291 nucleotides and contained open reading frames for six proteins of molecular weight larger than 5 kDa. One of these (ORF1, 33.4 kDa) codes for a leucine-rich protein with the nucleoside triphosphate-binding motif GXGKS and may possibly participate in virus replication. The putative viral protein encoded by ORF3 (6.4 kDa) is a positively charged arginine-rich protein with homology to the capsid protein of nuclear polyhedrosis virus, and may represent the CFDV coat protein. CFDV DNA can form a stable stem structure of 10 GC base pairs subtending a loop sequence which in one orientation closely resembles the motif TAATATTAC conserved in a similar structural arrangement within the geminivirus group. Otherwise no sequence homology to DNA-containing plant viruses of the gemini- or caulimovirus groups was found. CFDV therefore represents a new taxonomic group of plant viruses.