Abstract: .alpha.-Amylase, an enzyme that hydrolyses starch, can be found in all plants. The modification of potato starch production, in particular, is important in the preparation of various food products. The present invention discloses nucleotide sequences of potato .alpha.-amylase genes and the corresponding amino acid sequences. The present invention also describes DNA probes comprising .alpha.-amylase nucleotide sequences, as well as expression vectors that produce active .alpha.-amylase enzymes. These expression vectors can be used to produce transgenic potato plants.

Abstract: A method of selecting genetically transformed cells from a population of cells comprising introducing a desired nucleotide sequence and a co-introduced nucleotide sequence into the genome of a cell whereby the desired nucleotide sequence or the co-introduced nucletoide sequence induces a positive effect by giving the transformed cells a competitive advantage when the population of cells are supplied with an inactive compound thereby allowing the transformed cells to be identified and selected from the non-transformed cells by means defined as positive selection; as well as cells transformed according to the method and plants derived therefrom. The invention further relates to novel glucuronide compounds including cytokinin glucuronide compounds for use in the method.

Abstract: .alpha.-Amylase, an enzyme that hydrolyzes starch, can be found in all plants. The modification of potato starch production, in particular, is important in the preparation of various food products. The present invention pertains to expression vectors for producing antisense .alpha.-amylase RNA which is complementary to, or which hybridizes specifically to, potato .alpha.-amylase mRNA. This invention also includes a vector system which operates to introduce into the genome of a plant an expression vector for producing antisense .alpha.-amylase RNA, and a microorganism of the genus Agrobacterium which contains such a vector system and which is capable of infecting a plant. This invention also provides a genetically modified plant containing in its genome an expression vector for producing antisense .alpha.-amylase RNA.

Abstract: .alpha.-Amylase, an enzyme that hydrolyses starch, can be found in all plants. The modification of potato starch production, in particular, is important in the preparation of various found products. The present invention discloses nucleotide sequences of potato .alpha.-amylase genes and the corresponding amino acid sequences. The present invention also describes DNA probes comprising .alpha.-amylase nucleotide sequences, as well as expression vectors that produce active .alpha.-amylase enzymes. These expression vectors can be used to produce transgenic potato plants.