During Agrobacterium infections, plant cell begins to synthesize Arginine derivatives called
During Agrobacterium infections, plant cell begins to synthesize Arginine derivatives called
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Correct Answer: Option B
Explanation
During Agrobacterium tumefaciens infection of plant cells: The bacterium attaches to wounded plant cells and senses phenolic wound signals (acetosyringone). The Ti (tumour-inducing) plasmid contains T-DNA (transfer DNA) and vir (virulence) genes. Vir proteins nick and transfer T-DNA as a single-stranded copy into the plant cell, where it integrates into the nuclear genome. T-DNA encodes: Ipt (isopentenyltransferase for cytokinin biosynthesis), iaaM+iaaH (for auxin biosynthesis — causing crown gall tumour), and OPINE SYNTHASE genes. Opines are condensation products of amino acids with-ketoacids or sugars — e.g. nopaline (Arg +-ketoglutarate), octopine (Arg + pyruvate), agropine. Agrobacterium catabolises opines using plasmid-encoded enzymes for carbon and nitrogen nutrition. Acetosyringone is the phenolic signal that induces vir genes, not the opine. Hygromycin is a selection antibiotic used in plant transformation.