title: CjbHLH1 homologs regulate sanguinarine biosynthesis in Eschscholzia californica cells.
abstract: Isoquinoline alkaloids (IQAs), terpenoid indole alkaloid and nicotine are some of the most studied alkaloids. Recently, several groups have reported that the biosynthesis of these alkaloids is regulated by basic helix-loop-helix (bHLH) transcription factors. Whereas the biosyntheses of nicotine and terpenoid indole alkaloid in Nicotiana plants and Catharanthus roseus are directly or indirectly regulated by Arabidopsis thaliana MYC2 homologs, a non-MYC2-type bHLH transcription factor, CjbHLH1, comprehensively regulates berberine biosynthesis in Coptis japonica. Interestingly, CjbHLH1 homologous genes were found in many IQA-producing plant species, which suggests that non-MYC2-type CjbHLH homologs are specifically associated with IQA biosynthesis. To test whether CjbHLH1 homologs are involved in the biosynthesis of IQA in a plant other than C. japonica, we isolated two genes homologous to CjbHLH1, i.e. EcbHLH1-1 and EcbHLH1-2, from Eschscholzia californica (California poppy). Stable transformants in which the expression levels of EcbHLH1 genes were constitutively suppressed by RNA interference (RNAi) showed a reduced expression of some IQA biosynthetic enzyme genes. A metabolite analysis confirmed that the suppression of EcbHLH1, particularly EcbHLH1-2, caused a decrease in sanguinarine accumulation in transgenic cultured cells. These results indicate that non-MYC2-type EcbHLH1s regulate IQA biosynthesis in California poppy like CjbHLH1 in C. japonica.
authors.affiliation: Department of Plant Gene and Totipotency, Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo, Kyoto, 606-8502 Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Department of Plant Gene and Totipotency, Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo, Kyoto, 606-8502 Japan.
authors.forename: Yukiya
authors.initials: Y
authors.lastname: Motomura
authors.affiliation: Department of Plant Gene and Totipotency, Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo, Kyoto, 606-8502 Japan fsato@lif.kyoto-u.ac.jp.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Sato
mesh_terms: D000085:Acetates / Q000494:pharmacology; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D053119:Benzophenanthridines / Q000096:biosynthesis* / Q000737:chemistry; D001599:Berberine / Q000737:chemistry; D053898:Biosynthetic Pathways / Q000187:drug effects / Q000235:genetics; D039323:Coptis / Q000378:metabolism*; D003517:Cyclopentanes / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D031675:Eschscholzia / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D007546:Isoquinolines / Q000737:chemistry; D009928:Organ Specificity / Q000187:drug effects; D054883:Oxylipins / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D000085:Acetates; D051792:Basic Helix-Loop-Helix Proteins; D053119:Benzophenanthridines; D001599:Berberine; D003517:Cyclopentanes; D007546:Isoquinolines; D054883:Oxylipins; D010940:Plant Proteins; D012333:RNA, Messenger; C072239:methyl jasmonate; C005705:sanguinarine
keywords: Basic helix–loop–helix; Eschscholzia californica (California poppy); Isoquinoline alkaloids; Transcriptional regulation