title: Endosperm-specific expression of serotonin N-hydroxycinnamoyltransferase in rice.
abstract: Serotonin N-hydroxycinnamoyltransferase (SHT) is a key enzyme in the synthesis of feruloylserotonin (FS) and 4-coumaroylserotonin (CS). These serotonin derivatives show strong antioxidant activity, making them valuable for both nutritional and pharmacological use in humans. Ectopic expression of SHT under the control of the endosperm specific-glutelin and prolamin promoters from rice was produced via Agrobacterium-mediated transformation. SHT expression was confirmed by Southern blot analysis, followed by Northern blotting and SHT enzyme activity analyses using total RNA and protein, respectively, extracted from transgenic seeds. The glutelin A3 (GluA3) promoter produced low SHT mRNA expression in rice seeds, whereas the prolamin promoter expressed high levels of SHT mRNA. In spite of the ectopic expression of SHT in rice seeds, both transgenic genotypes accumulated levels of serotonin derivatives similar to those found in wild-type rice. Furthermore, our data suggest that serotonin, rather than phenylpropanid-CoAs, is the rate-limiting substrate in the biosynthesis of serotonin derivatives in SHT-overexpressing transgenic rice seeds.
authors.affiliation: Department of Molecular Biotechnology, Agricultural Plant Stress Research Center, Biotechnology Research Institute, Chonnam National University, Gwangju, Republic of Korea.
authors.forename: Kyungjin
authors.initials: K
authors.lastname: Lee
authors.forename: Kiyoon
authors.initials: K
authors.lastname: Kang
authors.forename: Munyoung
authors.initials: M
authors.lastname: Park
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Woo
authors.forename: Kyoungwhan
authors.initials: K
authors.lastname: Back
mesh_terms: D047068:Arylalkylamine N-Acetyltransferase / Q000378:metabolism*; D003373:Coumaric Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D012275:Oryza / Q000201:enzymology* / Q000235:genetics*; D030821:Plants, Genetically Modified; D012701:Serotonin / Q000031:analogs & derivatives* / Q000096:biosynthesis* / Q000378:metabolism; D014439:Tyramine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D003373:Coumaric Acids; D012701:Serotonin; C074004:feruloyltyramine; D047068:Arylalkylamine N-Acetyltransferase; C114774:N-(p-coumaroyl)serotonin; D014439:Tyramine