Pseudorecombination between infectious cloned DNA components of tomato mottle and bean dwarf mosaic geminiviruses

Abstract

A newly described whitefly-transmitted geminivirus infecting tomato plants in Florida induces yellow mottling symptoms on leaves, and stunted and distorted growth. The DNA-A and DNA-B components were cloned from extracts of field-infected tomato tissue; excised monomers or uncut tandem dimers of these clones were infectious when co-inoculated on to Nicotiana benthamiana by rub-inoculation. Tomato plants inoculated directly with the DNA-A and DNA-B dimers, or indirectly by sap or graft transmission from N. benthamiana plants previously infected with the dimers, developed symptoms similar to those observed in fieldinfected plants. This tomato geminivirus is different from previously characterized geminiviruses, and has been named tomato mottle geminivirus (ToMoV). DNA sequence comparisons revealed that ToMoV is closely related to bean dwarf mosaic geminivirus (BDMV) and abutilon mosaic geminivirus. Infectious pseudorecombinants were made by exchanging the cloned infectious DNA components of ToMoV and BDMV and inoculating N. benthamiana plants. The presence of the inoculated DNA components in systemically infected plants was confirmed by characterization of DNA-A and DNA-B fragments amplified by the polymerase chain reaction. This is the first report ofpseudorecombination between two distinct geminiviruses. The implications of this finding in geminivirus evolution are discussed.

Molecular characterization of begomoviruses and DNA satellites from Vietnam: additional evidence that the New World geminiviruses were present in the Old World prior to continental separation

“…The majority of the viruses characterized during the current study were isolated from weeds that can serve as important virus reservoirs (Gilbertson et al, 1993;Stonor et al, 2003). Viruses in mixed infections may recombine, resulting in a novel virus that can cross host barriers.…”

Pseudorecombination and complementation between potato yellow mosaic geminivirus and tomato golden mosaic geminivirus

“…The only combination capable of forming pseudorecombinants with different ACI recognition sequences is BDMV and ToMoV (Gilbertson et al, 1993) whose predicted AC1 binding motifs diverge at one nucleotide position via a conservative G/A replacement. The BDMV/ToMoV pseudorecombinants did not replicate as efficiently as the homologous combinations which suggests that even a single nucleotide difference significantly interferes with the interaction between AC1 and its recognition sequence.…”

“…The viability of pseudorecombinants produced by reassortment of the genome components of strains of the subgroup III geminiviruses, African cassava mosaic virus (ACMV), squash leaf curl virus (SqLCV), TGMV and bean golden mosaic virus (Stanley et al, 1985;Morris et al, 1990;Lazarowitz, 1991 ;von Arnim & Stanley, 1992;Faria et al, 1994) or of tomato mottle virus (ToMoV) and bean dwarf mosaic virus (BDMV) (Gilbertson et al, 1993) implies that trans-acting functions are interchangeable between different strains of the same virus and between very closely related viruses. In contrast, attempts to produce infectious pseudorecombinants between other closely related subgroup III geminiviruses such as ACMV and TGMV, TGMV and AbMV, ACMV and Indian cassava mosaic virus (ICMV) (Frischmuth et al, 1993) and TGMV and SqLCV (Lazarowitz, 1991) were unsuccessful, even though they share common hosts.…”

Supervirulent pseudorecombination and asymmetric synergism between genomic components of two distinct species of begomovirus associated with severe tomato leaf curl disease in India

“…Viable pseudorecombinants have been produced in the laboratory by reassortment of the genomic components of closely related virus isolates of ACMV, squash leaf curl virus (SqLCV), tomato golden mosaic virus (TGMV) and bean golden mosaic virus (BGMV) (Stanley et al, 1985;Lazarowitz, 1991;von Arnim & Stanley, 1992;Ingham & Lazarowitz, 1993;Faria et al, 1994) or from isolates of the two species Tomato mottle virus and Bean dwarf mosaic virus (Gilbertson et al, 1993). However, in no case was pseudorecombination between viruses belonging to two different species shown to lead to a more virulent virus.…”