Characterization of a rice gene family encoding type-A diterpene cyclases.
We have previously isolated and characterized the rice (Oryza sativa) cDNAs, OsCyc1/OsCPS4, OsCyc2/OsCPS2, OsKS4, OsDTC1/OsKS7, OsDTC2/OsKS8 and OsKS10, which encode cyclases that are responsible for diterpene phytoalexin biosynthesis. Among the other members of this gene family, OsCPS1 and OsKS1 have been suggested as being responsible for gibberellin biosynthesis, OsKSL11 has recently been shown to encode stemodene synthase, and the functions of the three other diterpene cyclase genes in the rice genome, OsKS3, OsKS5 and OsKS6, have not yet been determined. In this study, we show that recombinant OsKS5 and OsKS6 expressed in E. coli converted ent-copalyl diphosphate into ent-pimara-8(14),15-diene and ent-kaur-15-ene, respectively. Neither product is a hydrocarbon precursor required in the biosynthesis of either gibberellins or phytoalexins. OsKS3 may be a pseudogene from which the translated product is a truncated enzyme. These results suggest that the diterpene cyclase genes responsible for gibberellin and phytoalexin biosynthesis are not functionally redundant.
Kanno
Yuri
Y
Department of Bioresource Engineering, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan.
Otomo
Kazuko
K
Kenmoku
Hiromichi
H
Mitsuhashi
Wataru
W
Yamane
Hisakazu
H
Oikawa
Hideaki
H
Toshima
Hiroaki
H
Matsuoka
Makoto
M
Sassa
Takeshi
T
Toyomasu
Tomonobu
T
D000595:Amino Acid Sequence; D001483:Base Sequence; D004224:Diterpenes / Q000378:metabolism*; D017343:Genes, Plant; D005875:Gibberellins / Q000096:biosynthesis; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010802:Phylogeny; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012717:Sesquiterpenes; D013729:Terpenes; D000094162:Phytoalexins
D004224:Diterpenes; D005875:Gibberellins; D011994:Recombinant Proteins; D012717:Sesquiterpenes; D013729:Terpenes; D000094162:Phytoalexins