Selection of transgenic rice plants using a herbicide tolerant form of the acetolactate synthase gene.

Acetolactate synthase (ALS) is an enzyme in the biosynthetic pathway for branched-chain amino acids, and bispyribac-sodium (BS), a pyrimidinyl carboxy herbicide, is a well-known inhibitor of ALS activity. However, it appears that a mutated form of rice ALS [OsmALS (W548L/S627I)] confers resistance to BS. We succeeded in using OsmALS with native OsALS promoter and terminator region for a selection marker of rice transformation. Because this selection marker cassette is originally from the rice endogenous genome, it can be expected to be publicly acceptable.