Reduced ethylene synthesis by transgenic tomatoes expressing S-adenosylmethionine hydrolase

Plant Mol Biol. 1994 Nov;26(3):781-90. doi: 10.1007/BF00028848.


We have utilized a gene from bacteriophage T3 that encodes the enzyme S-adenosylmethionine hydrolase (SAMase) to generate transgenic tomato plants that produce fruit with a reduced capacity to synthesize ethylene. S-adenosylmethionine (SAM) is the metabolic precursor of 1-aminocyclopropane-1-carboxylic acid, the proximal precursor to ethylene. SAMase catalyzes the conversion of SAM to methylthioadenosine and homoserine. To restrict the presence of SAMase to ripening fruit, the promoter from the tomato E8 gene was used to regulate SAMase gene expression. Transgenic tomato plants containing the 1.1 kb E8 promoter bore fruit that expressed SAMase during the breaker and orange stage of fruit ripening and stopped expression after the fruit fully ripened. Plants containing the 2.3 kb E8 promoter expressed SAMase at higher levels during the post-breaker phases of fruit ripening and had a substantially reduced capacity to synthesize ethylene.

MeSH terms

  • Bacteriophage T3 / enzymology
  • Bacteriophage T3 / genetics
  • Base Sequence
  • Ethylenes / biosynthesis*
  • Gene Expression Regulation
  • Genetic Vectors
  • Hydrolases / biosynthesis*
  • Hydrolases / genetics
  • Lycopersicon esculentum / genetics
  • Lycopersicon esculentum / growth & development
  • Lycopersicon esculentum / metabolism*
  • Molecular Sequence Data
  • Plant Growth Regulators / metabolism*
  • Plants, Genetically Modified / metabolism*
  • Promoter Regions, Genetic / genetics
  • Recombinant Fusion Proteins / biosynthesis
  • Rhizobium / genetics
  • Transformation, Genetic


  • Ethylenes
  • Plant Growth Regulators
  • Recombinant Fusion Proteins
  • ethylene
  • Hydrolases
  • adenosylmethionine hydrolase