Expression of early nodulin promoter gene in transgenic rice

We obtained transgenic rice plants carrying the alfalfa (Medicago sativa) M senod 12 promoters fused to the uidA (GUS) reporter gene. While transient e xpression of the constructs was not detectable, the Msenod 12B promoter was expressed in the stable rice transformants. GUS activity was detected in p roembryogenic calli, whereas in the regenerated plants, without external su pply of enod 12 inducers, it was found in the root vascular tissue. This ex pression pattern was changed, however, in the transgenic rice roots maintai ned in a 2,4-D-containing medium by microballistic application of the Nod f actor, NodRm-IV (C16 : 2,S) from Rhizobium meliloti, the microsymbiont of M . sativa.