What is the Difference Between Ti and Ri Plasmid?

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The main difference between Ti and Ri plasmids lies in their functions within bacterial cells and their association with different bacteria. Both Ti and Ri plasmids are disease-inducing plasmids found in plant pathogenic bacteria, but they have distinct characteristics:

  • Ti Plasmid: Found in the bacterium Agrobacterium tumefaciens, Ti plasmids cause crown gall disease in dicots. They are responsible for the overproduction of cytokinins and auxin hormones, which create swelling or galls on the crown of the plant. Ti plasmids are primarily associated with the ability to induce the formation of plant tumors.
  • Ri Plasmid: Found in the bacterium Agrobacterium rhizogenes, Ri plasmids cause hairy root disease in monocots. They are designed for autonomous replication within bacterial cells and are used more broadly in genetic research. Ri plasmids can also be used as vectors to transfer desired genes.

Both Ti and Ri plasmids have T-DNA (transfer DNA) that is integrated into the host plant, and they are used as vectors in recombinant DNA technology. However, Ti plasmids are associated with the transfer of genetic material into plant cells, while Ri plasmids resist incompatibility with other plasmids, allowing coexistence.

Comparative Table: Ti vs Ri Plasmid

The Ti and Ri plasmids are found in the bacteria Agrobacterium tumefaciens and Agrobacterium rhizogenes, respectively. They are both plant pathogenic bacteria, but they cause different diseases in plants and have distinct functions.

Feature Ti Plasmid Ri Plasmid
Bacterium Agrobacterium tumefaciens Agrobacterium rhizogenes
Disease Crown gall disease in dicots Hairy root disease in monocots
Function Encodes genes for tumor formation Encodes genes for root induction
T-DNA Transfer DNA integrated into the host plant Transfer DNA integrated into the host plant
Vector Use Used in recombinant DNA technology to insert genes of interest Can be used as a vector to transfer desired genes

Both Ti and Ri plasmids have T-DNA, which is integrated into the host plant's genome during infection. They are used as vectors in recombinant DNA technology due to their self-replicating nature.