The nucleotide sequence of an infectious clone of the geminivirus beet curly top virus

Abstract

A number of infectious clones of a Californian isolate of the leafhopper‐transmitted geminivirus beet curly top virus (BCTV) have been constructed from virus‐specific double‐stranded DNA isolated from infected Beta vulgaris and used to demonstrate a single component genome. The nucleotide sequence of one infectious clone has been determined (2993 nucleotides). Comparison with other geminiviruses has shown that the organisation of the genome closely resembles DNA 1 of the whitefly‐transmitted members. The four conserved coding regions of DNA 1 have highly homologous counterparts in BCTV with the exception of the putative coat protein which is more closely related to those of the leafhopper‐transmitted geminiviruses suggesting a strong interrelationship between coat protein and insect vector. A BCTV component equivalent to DNA 2 is not required for virus infection or transmission and has not been isolated from infected plants.

Evidence that DNA-A of a geminivirus associated with severe cassava mosaic disease in Uganda has arisen by interspecific recombination.

“…For example, most of the putative gene products of the leafhopper-transmitted beet curly top virus (BCTV), classified in subgroup ( l genus) II of the Geminiviridae, have affinities with those of whitefly-transmitted subgroup III geminiviruses whereas the CP is subgroup I-like. The BCTV genome was therefore speculated to have resulted from intergeneric recombination between a subgroup III and a subgroup I virus (Stanley et al, 1986 ;Rybicki, 1994 ;Padidam et al, 1995). The putative AC1 protein of pepper huasteco virus, found in Mexico, has a few amino acid residues typical of Old World and others typical of New World subgroup III geminiviruses, although the other gene products of this virus are typical of the New World viruses (Torres-Pacheco et al, 1993).…”

Complete nucleotide sequence of the geminivirus tomato yellow leaf curl virus, Thailand isolate

“…After the complete sequence of the TYLCV-Th genome had been derived, further analysis was carried out using sequence analysis software from DNASTAR Inc. Optimal alignments (pairwise and multiple) and estimating degrees of sequence identity between analogous DNA and predicted protein sequences of specific geminiviruses were made using the Megalign program. Geminiviruses used for the comparative analyses included: TYLCV-Th, TYLCV-I (Navot et al, 1991), TYLCV-S (Kheyr-Pour et al, 1991), TLCV , ACMV (Stanley & Gay, 1983), TGMV (Hamilton et al, 1984), BGMV (Howarth et al, 1985), squash leaf curl virus (SqLCV) (Lazarowitz & Lazdins, 1991), Chloris striate mosaic virus (CSMV; Andersen et al, 1988), MSV (Mullineaux et al, 1984), wheat dwarf virus (WDV) (MacDowell et al, 1985), Digitaria streak virus (DSV) (Donson et al, 1987), abutilon mosaic virus (AbMV) (Frischmuth et al, 1990) and BCTV (Stanley et al, 1986). The sequences of the intergenic regions of bean dwarf mosaic virus (BDMV; Gilbertson et al, 1991a) and tomato mottle virus (TMoV; Gilbertson et al, 1991b) were retrieved from the GenBank Sequence Database (accession numbers M88179 and M90494, respectively).…”

Tomato dwarf leaf curl virus, a new bipartite geminivirus associated with tomatoes and peppers in Jamaica and mixed infection with tomato yellow leaf curl virus

“…Phylogenetic analysis with the common region of DNA-A to nucleotide 499 of the cp gene placed CaLCV with SqLCV and, in a DNA-B dendrogram of the intergenic region between the bc1 and the common region and the entire common region, CaLCV was clustered between PHV and African cassava mosaic virus (ACMV). Similarly, the position of other geminiviruses in a phylogenetic tree differs according to the part of the genome used for analysis, e.g., PHV (Torres-Pacheco et al, 1993) and BCTV (Stanley et al, 1986;Howarth & Vandemark, 1989;Padidam et al, 1995).…”