Agrobacterium tumefaciens causes crown gall disease in plants by transferring their T-DNA which contains some oncogenic genes. At the site of the wound, these bacteria become accumulates and then transfer their T-DNA into host plant cells, which interact with host plant genomic DNA and cause tumor. With the help of knowledge, how the A.tumefaciens transfer their T-DNA to plant cells. And with the knowledge and use of the latest molecular biology techniques, A.tumefaciens is used as a tool for the transformation of our gene of interest into the host plant cells to make genetically modified plants. This review provides a working systematic review of the isolation, identification, and characterization of A.tumefaciens from the leguminous plants. This review also tells us how to transfer the T-DNA into a host plant cell and how to isolate the Agrobacterium tumefaciens from the root nodules of leguminous plants, first of all, collect the root nodules of leguminous plants then wash them properly and streak the isolates of root nodules on LB agar plates. then identify and characterize the Agrobacterium from the isolates because Agrobacterium and rhizobium stay together. For characterization, biochemical tests i.e gram staining and KOH tests performed to confirm the isolated bacteria is gram-negative. Some pathogenic tests such as carrot disk bioassay and potato disc confirm whether isolates caused a tumor or not.
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