A naturally occurring recombinant DNA-A of a typical bipartite begomovirus does not require the cognate DNA-B to infect Nicotiana benthamiana systemically

J Gen Virol. 2003 Mar;84(Pt 3):715-726. doi: 10.1099/vir.0.18783-0.

Abstract

Species of the genus Begomovirus (family Geminiviridae) found in the western hemisphere typically have a bipartite genome that consists of two 2.6 kb DNA genomic components, DNA-A and DNA-B. We have identified and cloned genomic components of a new tomato-infecting begomovirus from Brazil, for which the name Tomato crinkle leaf yellows virus (TCrLYV) is proposed, and a DNA-A variant of Tomato chlorotic mottle virus (ToCMV-[MG-Bt1]). Sequence analysis revealed that TCrLYV was most closely related to ToCMV, although it was sufficiently divergent to be considered a distinct virus species. Furthermore, these closely related viruses induce distinguishable symptoms in tomato plants. With respect to ToCMV-[MG-Bt1] DNA-A, evidence is presented that suggests a recombinant origin. It possesses a hybrid genome on which the replication compatible module (AC1 and replication origin) was probably donated by ToCMV-[BA-Se1] and the remaining sequences appear to have originated from Tomato rugose mosaic virus (ToRMV). Despite the high degree of sequence conservation with its predecessors, ToCMV-[MG-Bt1] differs significantly in its biological properties. Although ToCMV-[MG-Bt1] DNA-A did not infect tomato plants, it systemically infected Nicotiana benthamiana, induced symptoms of mottling and accumulated viral DNA in the apical leaves in the absence of a cognate DNA-B. The modular rearrangement that resulted in ToCMV-[MG-Bt1] DNA-A may have provided this virus with a more aggressive nature. Our results further support the notion that interspecies recombination may play a significant role in geminivirus diversity and their emergence as agriculturally important pathogens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Brazil
  • Cloning, Molecular
  • DNA, Viral / analysis*
  • Geminiviridae / classification
  • Geminiviridae / genetics*
  • Molecular Sequence Data
  • Nicotiana / virology*
  • Phylogeny
  • Recombination, Genetic*
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Solanum lycopersicum / virology*
  • Species Specificity

Substances

  • DNA, Viral