Agrobacterium rhizogenes GALLS protein substitutes for Agrobacterium tumefaciens single-stranded DNA-binding protein VirE2.
Agrobacterium tumefaciens and Agrobacterium rhizogenes transfer plasmid-encoded genes and virulence (Vir) proteins into plant cells. The transferred DNA (T-DNA) is stably inherited and expressed in plant cells, causing crown gall or hairy root disease. DNA transfer from A. tumefaciens into plant cells resembles plasmid conjugation; single-stranded DNA (ssDNA) is exported from the bacteria via a type IV secretion system comprised of VirB1 through VirB11 and VirD4. Bacteria also secrete certain Vir proteins into plant cells via this pore. One of these, VirE2, is an ssDNA-binding protein crucial for efficient T-DNA transfer and integration. VirE2 binds incoming ssT-DNA and helps target it into the nucleus. Some strains of A. rhizogenes lack VirE2, but they still transfer T-DNA efficiently. We isolated a novel gene from A. rhizogenes that restored pathogenicity to virE2 mutant A. tumefaciens. The GALLS gene was essential for pathogenicity of A. rhizogenes. Unlike VirE2, GALLS contains a nucleoside triphosphate binding motif similar to one in TraA, a strand transferase conjugation protein. Despite their lack of similarity, GALLS substituted for VirE2.
Hodges
Larry D
LD
Department of Microbiology, Oregon State University, Corvallis, Oregon 97331, USA.
Cuperus
Josh
J
Ream
Walt
W
D000098:Acetophenones / Q000494:pharmacology; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007473:Ion Channels / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D010957:Plasmids; D018085:Regulon; D012231:Rhizobium / Q000235:genetics* / Q000472:pathogenicity
D000098:Acetophenones; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D007473:Ion Channels; C051583:virE2 protein, Agrobacterium; C051667:acetosyringone