- Soil pathogenic bacteria cause tumors and galls in plants; inject through wounds.
- Ti region is transferred into host genome
- Here Ti stands for tumor inducing gene.
- Ti region contain T-DNA
- T-DNA has 4 genes,
a) tms1, tms2 – synthesis of IAA
b) tmr – production of cytokinin
c) os – opine synthesis
- Tms1, tms2 and tmr are called oncogenes and are involved in tumor production.
- Vir region is responsible or assist in T-DNA transfer and contain 6-8 operons.
- Removal of 3 oncogenes from T-DNA sequence is called disarming.
- Opines (amino acid derivative) serve carbon, nitrogen and energy source for the bacteria.
Fig: Agrobacterium tumefaciens
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