TITLE:
Review: Plant Binary Vectors of Ti Plasmid in Agrobacterium tumefaciens with a Broad Host-Range Replicon of pRK2, pRi, pSa or pVS1
AUTHORS:
Norimoto Murai
KEYWORDS:
Agrobacterium tumefaciens; Binary Vectors; pRK2; pRi; pSA; pVS1; T-DNA; Ti Plasmid
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.4,
April
25,
2013
ABSTRACT: This review
chronicles the development of the plant binary vectors of Ti plasmid in Agrobacterium tumefaciens during the last
30 years. A binary vector strategy was designed in 1983 to separate the T-DNA
region in a small plasmid from the virulence genes in avirulent T-DNA-less Ti plasmid. The small plant vectors with the
T-DNA region have been simply now called binary Ti vectors. A binary Ti vector
consist of a broad host-range replicon for propagation in A. tumeraciens, an antibiotic resistance gene for bacterial
selection and the T-DNA region that would be transferred to the plant genome
via the bacterial virulence machinery.
The T-DNA region delimited by the right and left border sequences contains an
antibiotic resistance gene for plant selection, reporter gene, and/or any genes
of interest. The ColEI replicon was also added to the plasmid backbone to
enhance the propagation in Escherichia
coli. A general trend in the binary vector development has been to increase the
plasmid stability during a long co-cultivation period of A. tumefaciens with the target host plant tissues. A second trend
is to understand the molecular mechanism of broad host-range replication, and
to use it to reduce the size of plasmid for ease in cloning and for higher
plasmid yield in E. coli. The broad
host-range replicon of VS1 was shown to be a choice of replicon over those of
pRK2, pRi and pSA because of the superior stability and of small
well-defined replicon. Newly developed plant binary vectors pLSU has the small
size of plasmid backbone (4566 bp) consisting of VS1 replicon (2654 bp), ColE1
replicon (715 bp), a bacterial kanamycin (999 bp) or tetracycline resistance
gene, and the T-DNA region (152 bp).