title: Characterization and evolutionary analysis of ent-kaurene synthase like genes from the wild rice species Oryza rufipogon.
abstract: Cultivated rice (Oryza sativa) possesses various labdane-related diterpene synthase genes, homologs of ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS) that are responsible for the biosynthesis of phytohormone gibberellins. The CPS homologs and KS like (KSL) homologs successively converted geranylgeranyl diphosphate to cyclic diterpene hydrocarbons via ent-copalyl diphosphate or syn-copalyl diphosphate in O. sativa. Consequently, a variety of labdane-related diterpenoids, including phytoalexin phytocassanes, momilactones and oryzalexins, have been identified from cultivated rice. Our previous report indicated that the biosynthesis of phytocassanes and momilactones is conserved in Oryza rufipogon, the progenitor of Asian cultivated rice. Moreover, their biosynthetic gene clusters, containing OsCPS2 and OsKSL7 for phytocassane biosynthesis and OsCPS4 and OsKSL4 for momilactone biosynthesis, are also present in the O. rufipogon genome. We herein characterized O. rufipogon homologs of OsKSL5, OsKSL6, OsKSL8 responsible for oryzalexin S biosynthesis, and OsKSL10 responsible for oryzalexins A-F biosynthesis, to obtain more evolutionary insight into diterpenoid biosynthesis in O. sativa. Our phytoalexin analyses showed that no accumulation of oryzalexins was detected in extracts from O. rufipogon leaf blades. In vitro functional analyses indicated that unlike OsKSL10, O. rufipogon KSL10 functions as an ent-miltiradiene synthase, which explains the lack of accumulation of oryzalexins A-F in O. rufipogon. The different functions of KSL5 and KSL8 in O. sativa japonica to those in indica are conserved in each type of O. rufipogon, while KSL6 functions (ent-isokaurene synthases) are well conserved. Our study suggests that O. sativa japonica has evolved distinct specialized diterpenoid metabolism, including the biosynthesis of oryzalexins.
authors: Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan. Electronic address: toyomasu@tds1.tr.yamagata-u.ac.jp.
authors: Tomonobu
authors: T
authors: Toyomasu
authors: Department of Biosciences, Teikyo University, Utsunomiya, 320-8551, Japan.
authors: Koji
authors: K
authors: Miyamoto
authors: Plant Genetics Laboratory, National Institute of Genetics, Shizuoka, 411-8540, Japan.
authors: Matthew R
authors: MR
authors: Shenton
authors: Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan.
authors: Arisa
authors: A
authors: Sakai
authors: Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan.
authors: Chizu
authors: C
authors: Sugawara
authors: United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, 183-8509, Japan.
authors: Kiyotaka
authors: K
authors: Horie
authors: United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, 183-8509, Japan.
authors: Hiroshi
authors: H
authors: Kawaide
authors: United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, 183-8509, Japan; College of Agriculture, Ibaraki University, Ibaraki, 300-0393, Japan.
authors: Morifumi
authors: M
authors: Hasegawa
authors: Yamagata Integrated Agricultural Research Center, Tsuruoka, 999-7601, Japan.
authors: Masaru
authors: M
authors: Chuba
authors: Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan.
authors: Wataru
authors: W
authors: Mitsuhashi
authors: Department of Biosciences, Teikyo University, Utsunomiya, 320-8551, Japan.
authors: Hisakazu
authors: H
authors: Yamane
authors: Plant Genetics Laboratory, National Institute of Genetics, Shizuoka, 411-8540, Japan.
authors: Nori
authors: N
authors: Kurata
authors: Biotechnology Research Center, The University of Tokyo, Bunkyo-ku, 113-8657, Japan.
authors: Kazunori
authors: K
authors: Okada
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics*; D017124:Conserved Sequence; D019143:Evolution, Molecular; D017343:Genes, Plant / Q000235:genetics*; D018745:Genome, Plant / Q000235:genetics; D012275:Oryza / Q000145:classification* / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D019883:Alkyl and Aryl Transferases; C105712:ent-kaurene synthetase B
keywords: Biosynthesis; Diterpene synthase; Evolution; Rice; Wild species