A WD40 Repeat Protein from Medicago truncatula Is Necessary for Tissue-Specific Anthocyanin and Proanthocyanidin Biosynthesis But Not for Trichome Development
A WD40 Repeat Protein from Medicago truncatula Is Necessary for Tissue-Specific Anthocyanin and Proanthocyanidin Biosynthesis But Not for Trichome Development
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DOI：
10.1104/pp.109.144022
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发表时间：
2009-11-01
期刊：
影响因子：
7.4
通讯作者：
Dixon, Richard A.
中科院分区：
文献类型：
--
作者：
Pang, Yongzhen;Wenger, Jonathan P.;Dixon, Richard A.
WD40重复蛋白调节种子中花青素、原花青素(PAS)和粘液的生物合成以及毛状体和根毛的发育。我们用反转录转座子标签的方法克隆了一个WD40重复蛋白基因，并对其进行了鉴定。缺乏MtWD40-1的表达阻止了粘液和一系列酚类化合物的积累，包括PAS、表儿茶素、其他类黄酮和苯甲酸，降低了表儿茶素的水平，而对花中的其他类黄酮没有相应的影响，降低了根中的异黄酮水平，但不损害毛状体或根毛的发育。MtWD40-1是结构性表达的，在种皮中表达最高，其转录谱在时间上与PA生物合成基因的转录谱平行。转录谱分析表明，在MtWD40-1基因中插入反转录转座子的元宝莲品系中，许多类黄酮生物合成基因以组织特异性的方式下调。MtWD40-1补充了拟南芥透明种皮突变体的花青素、PA和毛状体表型。我们讨论了MtWD40-1在元宝草天然产物形成中的作用，以及该基因在饲用豆科紫花苜蓿(Medicago Sativa)中进行Pas工程的潜在用途。
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).