Abstract: Disclosed is a method for producing a transgenic angiosperm plant, particularly a monocot, comprising the step of transforming an immature embryo of an angiosperm plant with a DNA fragment expressible in said angiosperm embryo, said DNA fragment comprising a promoter region derived from an &agr;-amylase gene of a plant, and an exogenous gene encoding a desired gene product, said promoter region being inducible under a sugar-depleted or sugar-free condition to promote the expression of said gene, whereby at least a part of the resultant transgenic angiosperm plant has the ability to express said gene product. Transgenic angiosperm plants and transgenic angiosperm plant seeds are also disclosed. The transgenic angiosperm plant seeds may have application in the industrial production of alcohol, beer, glucose and the like.

Abstract: The present invention is directed to a method for the production of a transgenic plant of rice crop comprising the steps of infecting an immature embryo of rice crop with the genus Agrobacterium for transformation; co-culturing the infected embryo with a dicot suspension culture during the step of transformation; allowing the transformed embryo to grow into a callus in a selective medium comprising a sufficient amount of a plant growth hormone for the growth of rice crop; and allowing the cultured callus to regenerate root and shoot in a regeneration medium comprising a pre-determined amount of nutrients for the growth of rice crop. The invention is further directed to a transformed rice plant made by methods of this invention.

Abstract: The present invention is directed to a method for producing a gene product by expressing a gene encoding the gene product in angiosperm host cells, comprising the steps of constructing a vector expressible in angiosperm host cells, the vector comprising a promoter region derived from an .alpha.-amylase gene of a plant, and a gene encoding a desired gene product; transforming a compatible angiosperm host cell with the vector; cultivating the resultant transformant host cell; subjecting the cultivated transformant host cell to a sugar-depleted or sugar-free condition to promote the expression of the gene under the control of the promoter region; and recovering the expressed gene product.

Abstract: Disclosed is a method for producing a gene product by expressing a gene encoding said gene product in plant host cells, comprising the steps of: constructing a vector expressible in plant host cells, the vector comprising a promoter region derived from an .alpha.-amylase gene of a plant, and a gene encoding a desired gene product; transforming a compatible plant host cell with the vector; cultivating the resultant transformant host cell; subjecting the cultivated transformant host cell to a sugar-depleted or sugar-free condition to promote the expression of the gene under the control of the promoter region; and recovering the expressed gene product. Also disclosed is a method for producing a gene product method which comprises the steps of: constructing a vector expressible in plant host cells, the vector comprising a promoter region derived from an .alpha.