摘要 |
A method of increasing nodulation of a plant capable of being nodulated by Bradyrhizobium sp. (Parasponis) is provided comprising infecting said plant with a Bradyrhizobium sp. (Parasponia) species mutated such that nodK is non-functional. One such method of mutation involves insertion upstream of nodABC constitutive promoter sequences capable of activating nodABC. The invention is exemplified by the inoculation of siratro with mutated Bradyrhizobium sp. (Parasponia) mutated by insertion of nptII promoter sequences in nodK upstream of nodABC so as to activate nodABC. As compared with inoculation with the corresponding wild-type Bradyrhizobium sp. (Parasponia), nodulation onset occurred five days earlier, nodulation number was doubled, and a 120% enhancement of plant yield was shown. Similar results were obtained regardless of the orientation of the nptII promoter-containing sequences within the nodK coding sequence.
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