A naturally occurring recombinant DNA-A of a typical bipartite begomovirus does not require the cognate DNA-B to infect Nicotiana benthamiana systemically.
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.
Galvão
Rafaelo M
RM
Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
Mariano
Andrea C
AC
Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
Luz
Dirce F
DF
Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
Alfenas
Poliane F
PF
Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
Andrade
Eduardo C
EC
Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
Zerbini
Francisco M
FM
Departamento de Fitopatologia/BIOAGRO, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
Almeida
Márcia R
MR
Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
Fontes
Elizabeth P B
EPB
Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. PH Rolfs s/n, 36571.000 Viçosa-MG, Brazil.
D001483:Base Sequence; D001938:Brazil; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000032:analysis*; D017791:Geminiviridae / Q000145:classification / Q000235:genetics*; D018551:Solanum lycopersicum / Q000821:virology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011995:Recombination, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014026:Nicotiana / Q000821:virology*
D004279:DNA, Viral