Abstract: Plants, particularly cereal plants, which have improved ability to synthesise starch at elevated or lowered temperatures and/or to synthesise starch with an altered fine structure are produced by inserting into the genome of the plant (i) a gene(s) encoding a form of an enzyme of the starch or glycogen biosynthetic pathway, particularly soluble starch synthase and/or branching enzyme and/or glycogen synthase, which display an activity which continues to increase over a temperature range over which the activity would normally be expected to decrease, and/or (ii) a gene(s) encoding sense and anti-sense constructs of enzymes of the starch biosynthetic pathway, particularly soluble starch synthase and/or branching enzyme and/or glycogen synthase, which alters the natural ratios of expression of the said enzymes or inserts enzymes with special structural characteristics which alter the natural branching pattern in starch.

Abstract: A method is provided for making fruit (particularly tomatoes) having increased solids content which comprises cultivating fruit-bearing plants in which expression of genes homologous to pTOM36 is at least partially inhibited. For this purpose the fruit may be transformed with DNA constructs comprising a DNA sequence homologous to some or all of the gene encoded by the clone pTOM36. The clone is adapted to generate sense or antisense RNA under control of a plant promoter.

Abstract: DNA clones, e.g. M13-1, comprising at least part of a gene derived from melon that encodes ethylene-forming enzyme. Such clones may comprise DNA constructs including plant promoters capable of expressing RNA in plant cells. Such constructs may be used to inhibit production of ethylene-forming enzyme in transformed plants, and thereby to produce slower-ripening fruit, particularly melons. The clones may be obtained by PCR using specific oligo-nucleotide primers.

Abstract: DNA clones, e.g. P13-B, comprising at least part of a gene derived from peach that encodes ethylene-forming enzyme. Such clones may comprise DNA constructs including plant promoters capable of expressing RNA in plant cells. Such constructs may be used to inhibit production of ethylene-forming enzyme in transformed plants, and thereby to produce slower-ripening fruit, particularly peaches. The clones may be obtained by PCR using specific oligo-nucleotide primers.

Abstract: DNA construct for use in transforming plant cells comprises and exogenous gene with upstream promoter and downstream terminator sequences, the promoter being a DNA sequence of not less than about 5 kilobases homologous to the DNA control sequence found upstream of the tomato PG gene. Preferably the terminator is homologous to the DNA control sequence of about 1.6 kilobases found downstream of the tomato polygalacturonase gene. Enhanced expression of the exogenous gene is obtained. The invention also included plant cells containing such constructs and plants derived therefrom.

Abstract: The gene of the construct pTOM5 is involved in the carotenoid pathway, which produces carotenes, lutein, xanthophylls, and pigments such as lycopene. The invention proposes to modify (inhibit or promote) the synthesis of such compounds in plants using novel DNA constructs comprising a DNA sequence homologous to some or all of the gene encoded by the clone pTOM5, preceded by a plant promoter. In particular, colour of plant parts, especially fruit, may be modified. Yellow tomatoes are disclosed.

Abstract: DNA constructs useful for modifying the ripening behavior of fruit comprise a transcriptional initiation region operative in plants positioned for transcription of a DNA sequence homologous to some or all of a fruit-ripening gene encoded by either of the clones pTOM136 or pTOM66, so that the construct can generate RNA in plant cells. Also plant cells and plants transformed with such constructs.

Abstract: DNA constructs comprise a DNA sequence homologous to some or all of the gene encoded by the clone pTOM36. The constructs may further comprise a transcriptional initiation region operative in plants for transcribing this DNA sequence, optionally in the antisense direction to produce mRNA complementary to the pTOM36 gene. Transformed plant cells and plants may be derived from such constructs: fruit from the plants (such as tomatoes) are expected to have modified ripening properties.