title: Down-regulation of Kelch domain-containing F-box protein in Arabidopsis enhances the production of (poly)phenols and tolerance to ultraviolet radiation.
abstract: Phenylpropanoid biosynthesis in plants engenders myriad phenolics with diverse biological functions. Phenylalanine ammonia-lyase (PAL) is the first committed enzyme in the pathway, directing primary metabolic flux into a phenylpropanoid branch. Previously, we demonstrated that the Arabidopsis (Arabidopsis thaliana) Kelch domain-containing F-box proteins, AtKFB01, AtKFB20, and AtKFB50, function as the negative regulators controlling phenylpropanoid biosynthesis via mediating PAL's ubiquitination and subsequent degradation. Here, we reveal that Arabidopsis KFB39, a close homolog of AtKFB50, also interacts physically with PAL isozymes and modulates PAL stability and activity. Disturbing the expression of KFB39 reciprocally affects the accumulation/deposition of a set of phenylpropanoid end products, suggesting that KFB39 is an additional posttranslational regulator responsible for the turnover of PAL and negatively controlling phenylpropanoid biosynthesis. Furthermore, we discover that exposure of Arabidopsis to ultraviolet (UV)-B radiation suppresses the expression of all four KFB genes while inducing the transcription of PAL isogenes; these data suggest that Arabidopsis consolidates both transcriptional and posttranslational regulation mechanisms to maximize its responses to UV light stress. Simultaneous down-regulation of all four identified KFBs significantly enhances the production of (poly)phenols and the plant's tolerance to UV irradiation. This study offers a biotechnological approach for engineering the production of useful phenolic chemicals and for increasing a plant's resistance to environmental stress.
authors.affiliation: Biological, Environmental, and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York 11973 (X.Z., M.G., H.Y., C.-J.L.);College of Art and Science, Shanxi Agriculture University, Taigu, Shanxi 030801, People's Republic of China (C.G.); andBiochemistry and Cell Biology Department, Stony Brook University, Stony Brook, New York 11972 (H.Y.).
authors.forename: Xuebin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Biological, Environmental, and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York 11973 (X.Z., M.G., H.Y., C.-J.L.);College of Art and Science, Shanxi Agriculture University, Taigu, Shanxi 030801, People's Republic of China (C.G.); andBiochemistry and Cell Biology Department, Stony Brook University, Stony Brook, New York 11972 (H.Y.).
authors.forename: Mingyue
authors.initials: M
authors.lastname: Gou
authors.affiliation: Biological, Environmental, and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York 11973 (X.Z., M.G., H.Y., C.-J.L.);College of Art and Science, Shanxi Agriculture University, Taigu, Shanxi 030801, People's Republic of China (C.G.); andBiochemistry and Cell Biology Department, Stony Brook University, Stony Brook, New York 11972 (H.Y.).
authors.forename: Chunrong
authors.initials: C
authors.lastname: Guo
authors.affiliation: Biological, Environmental, and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York 11973 (X.Z., M.G., H.Y., C.-J.L.);College of Art and Science, Shanxi Agriculture University, Taigu, Shanxi 030801, People's Republic of China (C.G.); andBiochemistry and Cell Biology Department, Stony Brook University, Stony Brook, New York 11972 (H.Y.).
authors.forename: Huijun
authors.initials: H
authors.lastname: Yang
authors.affiliation: Biological, Environmental, and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York 11973 (X.Z., M.G., H.Y., C.-J.L.);College of Art and Science, Shanxi Agriculture University, Taigu, Shanxi 030801, People's Republic of China (C.G.); andBiochemistry and Cell Biology Department, Stony Brook University, Stony Brook, New York 11972 (H.Y.) cliu@bnl.gov.
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Liu
mesh_terms: D000222:Adaptation, Physiological / Q000528:radiation effects*; D000872:Anthocyanins / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D004795:Enzyme Stability / Q000528:radiation effects; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D005419:Flavonoids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D007527:Isoenzymes / Q000378:metabolism; D008031:Lignin / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D010802:Phylogeny; D030821:Plants, Genetically Modified; D059808:Polyphenols / Q000096:biosynthesis*; D011485:Protein Binding / Q000528:radiation effects; D034622:RNA Interference / Q000528:radiation effects; D036226:Seedlings / Q000254:growth & development / Q000528:radiation effects; D013634:Tannins / Q000378:metabolism; D014466:Ultraviolet Rays; D015854:Up-Regulation / Q000528:radiation effects
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; C582933:At2g44130 protein, Arabidopsis; D044783:F-Box Proteins; D005419:Flavonoids; D007527:Isoenzymes; D059808:Polyphenols; D013634:Tannins; D008031:Lignin; D010650:Phenylalanine Ammonia-Lyase