title: Functional characterization of a chalcone synthase from the liverwort Plagiochasma appendiculatum.
abstract: A chalcone synthase gene ( PaCHS ) was isolated and functionally characterized from liverwort. The ectopic expression of PaCHS in Marchantia paleacea callus raised the flavonoids content. Chalcone synthase (CHS; EC 2.3.1.74) is pivotal for the biosynthesis of flavonoid and anthocyanin pigments in plants. It produces naringenin chalcone by condensing one p-coumaroyl- and three malonyl-coenzyme A thioesters through a polyketide intermediate that is cyclized by intramolecular Claisen condensation. Although CHSs of higher plants have been extensively studied, enzyme properties of the CHSs in liverworts have been scarcely characterized. In this study, we report the cloning and characterization of CHS (designated as PaCHS) from the liverwort Plagiochasma appendiculatum. The gene product was 60-70 % identical with chalcone synthases from other species, and contained the characteristic conserved Cys-His-Asn catalytic triad. The recombinant PaCHS was able to catalyze p-coumaroyl-CoA and malonyl-CoA to generate naringenin in vitro. Heterologously expressed PaCHS protein showed similar kinetic properties to those of higher plant CHS. The ectopic expression of PaCHS in Marchantia paleacea callus raised the content of the total flavonoids. These results suggested that PaCHS played a key role in the flavonoids biosynthesis in liverworts. Furthermore, when the thallus of P. appendiculatum was treated with abiotic stress inducers methyl jasmonate, salicylic acid and abscisic acid, PaCHS expression was enhanced. This is the first time that a CHS in liverworts has been functionally characterized.
authors.affiliation: Key Laboratory of Chemical Biology of Natural Products, Ministry of Education School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, China.
authors.forename: Hai-Na
authors.initials: HN
authors.lastname: Yu
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.forename: Shuai
authors.initials: S
authors.lastname: Gao
authors.forename: Ai-Xia
authors.initials: AX
authors.lastname: Cheng
authors.forename: Hong-Xiang
authors.initials: HX
authors.lastname: Lou
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000085:Acetates / Q000494:pharmacology; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000378:metabolism; D053898:Biosynthetic Pathways; D047188:Chalcones / Q000737:chemistry / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D044950:Flavanones / Q000737:chemistry / Q000378:metabolism; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism*; D015870:Gene Expression; D035926:Hepatophyta / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D047008:Marchantia / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D054883:Oxylipins / Q000494:pharmacology; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology*; D011994:Recombinant Proteins; D020156:Salicylic Acid / Q000494:pharmacology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D019076:Transgenes
chemical_list: D000085:Acetates; D000872:Anthocyanins; D047188:Chalcones; D003517:Cyclopentanes; D044950:Flavanones; D005419:Flavonoids; D054883:Oxylipins; D010937:Plant Growth Regulators; D011994:Recombinant Proteins; D000040:Abscisic Acid; C027329:naringenin chalcone; C072239:methyl jasmonate; D000217:Acyltransferases; C020141:flavanone synthetase; C005273:naringenin; D020156:Salicylic Acid