Efficient vir Gene Induction in Agrobacterium tumefaciens Requires virA, virG, and vir Box from the Same Ti Plasmid
AUTOR(ES)
Krishnamohan, Atmakuri
FONTE
American Society for Microbiology
RESUMO
The vir genes of octopine, nopaline, and l,l-succinamopine Ti plasmids exhibit structural and functional similarities. However, we observed differences in the interactions between octopine and nopaline vir components. The induction of an octopine virEA6::lacZ fusion (pSM358cd) was 2.3-fold higher in an octopine strain (A348) than in a nopaline strain (C58). Supplementation of the octopine virGA6 in a nopaline strain with pSM358 did not completely restore virEA6 induction. However, addition of the octopine virAA6 to the above strain increased virEA6 induction to a level almost comparable to that in octopine strains. In a reciprocal analysis, the induction of a nopaline virEC58::cat fusion (pUCD1553) was two- to threefold higher in nopaline (C58 and T37) strains than in octopine (A348 and Ach5) and l,l-succinamopine (A281) strains. Supplementation of nopaline virAC58 and virGC58 in an octopine strain (A348) harboring pUCD1553 increased induction levels of virEC58::cat fusion to a level comparable to that in a nopaline strain (C58). Our results suggest that octopine and l,l-succinamopine VirG proteins induce the octopine virEA6 more efficiently than they do the nopaline virEC58. Conversely, the nopaline VirG protein induces the nopaline virEC58 more efficiently than it does the octopine virEA6. The ability of Bo542 virG to bring about supervirulence in tobacco is observed for an octopine vir helper (LBA4404) but not for a nopaline vir helper (PMP90). Our analyses reveal that quantitative differences exist in the interactions between VirG and vir boxes of different Ti plasmids. Efficient vir gene induction in octopine and nopaline strains requires virA, virG, and vir boxes from the respective Ti plasmids.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=95292Documentos Relacionados
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