Engineering Ti vectors
Remove tumor-inducing genes
Remove opine producing genes
Ti-plasmid are 200-800kb!
Need E.coli “shuttle” capacity
- ori, antibiotic marker like AmpR
- marker (neoR within plant expression cassette)
MCS (between left and right borders)
make binary system
- small shuttle vector with modified T-DNA
- large “disarmed” Ti-plasmid (vir)