BIOL 2303 Lecture Notes - Lecture 16: Nod Factor, Root Nodule, Rhizobia
18 Apr 2018
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Document Summary
Intimate relationship between two organisms, often developed through prolonged association and co-evaluation. Parasitic symbiosis: one partner benefits while the other is in adversely affected. Symbiosis between legume plants and nitrogen fixing bacteria. Bacteria in nodules fix nitrogen making it biologically available to the plant. Bacterium transfers a small piece of dna that is integrated into the plant genome. Mediated by a tumor inducing plasmid- ti plasmid. T-dna: sequence transferred into the plant cell contains oncogenes and opine genes. Vir genes: encode functions that promote the transfer of the t-dna into the plant. Opine degradation genes: allow the bacteria to use the opine produced by the plant tumor. Vira protein is a sensor kinase, responds to phenolic compounds secreted by the wounded plant tissue. Virg respons regulator protein is phosphorylated by kinase and turns on the expression of the rest of the vir genes.
