Occurrence of theobromine synthase genes in purine alkaloid-free species of Camellia plants.
Caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine) are purine alkaloids that are present in high concentrations in plants of some species of Camellia. However, most members of the genus Camellia contain no purine alkaloids. Tracer experiments using [8-(14)C]adenine and [8-(14)C]theobromine showed that the purine alkaloid pathway is not fully functional in leaves of purine alkaloid-free species. In five species of purine alkaloid-free Camellia plants, sufficient evidence was obtained to show the occurrence of genes that are homologous to caffeine synthase. Recombinant enzymes derived from purine alkaloid-free species showed only theobromine synthase activity. Unlike the caffeine synthase gene, these genes were expressed more strongly in mature tissue than in young tissue.
Ishida
Mariko
M
Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan.
Kitao
Naoko
N
Mizuno
Kouichi
K
Tanikawa
Natsu
N
Kato
Misako
M
D000595:Amino Acid Sequence; D028244:Camellia / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D019143:Evolution, Molecular; D017343:Genes, Plant; D008780:Methyltransferases / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017385:Sequence Homology; D013379:Substrate Specificity; D013805:Theobromine / Q000096:biosynthesis*
D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D008780:Methyltransferases; C120479:caffeine synthase; D013805:Theobromine