title: A WD40 repeat protein from Medicago truncatula is necessary for tissue-specific anthocyanin and proanthocyanidin biosynthesis but not for trichome development.
abstract: WD40 repeat proteins regulate biosynthesis of anthocyanins, proanthocyanidins (PAs), and mucilage in the seed and the development of trichomes and root hairs. We have cloned and characterized a WD40 repeat protein gene from Medicago truncatula (MtWD40-1) via a retrotransposon-tagging approach. Deficiency of MtWD40-1 expression blocks accumulation of mucilage and a range of phenolic compounds, including PAs, epicatechin, other flavonoids, and benzoic acids, in the seed, reduces epicatechin levels without corresponding effects on other flavonoids in flowers, reduces isoflavone levels in roots, but does not impair trichome or root hair development. MtWD40-1 is expressed constitutively, with highest expression in the seed coat, where its transcript profile temporally parallels those of PA biosynthetic genes. Transcript profile analysis revealed that many genes of flavonoid biosynthesis were down-regulated in a tissue-specific manner in M. truncatula lines harboring retrotransposon insertions in the MtWD40-1 gene. MtWD40-1 complemented the anthocyanin, PA, and trichome phenotypes of the Arabidopsis (Arabidopsis thaliana) transparent testa glabrous1 mutant. We discuss the function of MtWD40-1 in natural product formation in M. truncatula and the potential use of the gene for engineering PAs in the forage legume alfalfa (Medicago sativa).
authors.affiliation: Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401, USA.
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Pang
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Wenger
authors.forename: Katie
authors.initials: K
authors.lastname: Saathoff
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Peel
authors.forename: Jiangqi
authors.initials: J
authors.lastname: Wen
authors.forename: David
authors.initials: D
authors.lastname: Huhman
authors.forename: Stacy N
authors.initials: SN
authors.lastname: Allen
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Tang
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Cheng
authors.forename: Million
authors.initials: M
authors.lastname: Tadege
authors.forename: Pascal
authors.initials: P
authors.lastname: Ratet
authors.forename: Kirankumar S
authors.initials: KS
authors.lastname: Mysore
authors.forename: Lloyd W
authors.initials: LW
authors.lastname: Sumner
authors.forename: M David
authors.initials: MD
authors.lastname: Marks
authors.forename: Richard A
authors.initials: RA
authors.lastname: Dixon
mesh_terms: D000269:Adhesives / Q000378:metabolism; D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000096:biosynthesis*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D046913:Medicago truncatula / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D020411:Oligonucleotide Array Sequence Analysis; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development*; D044945:Proanthocyanidins / Q000096:biosynthesis*; D018626:Retroelements; D016415:Sequence Alignment
chemical_list: D000269:Adhesives; D000872:Anthocyanins; D018744:DNA, Plant; D010940:Plant Proteins; D044945:Proanthocyanidins; D018626:Retroelements