Transformation of plant by Agrobacterium Tumefaciens and rhizogenes mediated gene transfer ppt

Agrobacterium rhizogenes-mediated gene transfer in plants:Agrobacterium virulence and selection of transformation

Introduction-:

•         Rod shaped  gram negative bacterium Cause  diseases like crown gall and hairy roots disease in many dicotyledonous plants.
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•          The bacteria transfer a tumor inducing plasmid Agrobacterium mediated genetic transformation is the most widely used method of transferring genes into plants.
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•          The genomic integration of a set of genes is mediated through a specific transfer DNA from the Ri plasmid. 
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      What is a Agrobacterium rhizogenes ?

Agrobacterium rhizogenes is a gram-negative,rod shaped soil bacterium.Rhizogenes cause Hariy-root disease and formation and proliferate multi-branched adventitious roots at the site of infection  called hairy roots.

Agrobacterium the causative agent of hairy root syndrome is a common soil organism capable of entering a plant through a wound and causing a proliferation of secondary roots.

T-DNA -: 

The transfer DNA is the part of DNA, of the tumor-inducing plasmid of some species of Agrobacterium rhizogenes. The T-DNA is transferred from bacterium into the host plant nuclear DNA genome.The T-DNA is bordered by 25bp repeats on each end. Transfer is RB and LB require the vir genes of the Ti plasmid.

Ri plasmid-:

Ri plasmid are large 200 to greater than 800kb and contain one or more regions of T-DNA and virulence region. Ri plasmid is a circular and larger plasmid harbored by agrobacterium rhizogenes. The genes Ri plasmid T-DNA direct a variety of phenotopic traits in the transformed plant cells increased synthesis of two morphogenic auxins and cytokinin. The tumor synthesis specific compound called opines. Ri plasmid have been isolated from a variety of strains and appear to within two classes.

1.Mannopin 2.Agropine

Secondary metabolite: 

Hairy root culture are characterized by a high growth rate and are able to synthesize root derived secondary metabolite. Root culture exogenous phytohormone supply and grow very slowly.

Source of root derived phytochemicals use as pharmaceuticals , cosmetic and food additives.

Hairy root source of new cells are in the tips so proliferation occurs apical meristem and laterals from behind elongation zone. Growth pattern lead to accumulation of biomass in root culture.