A multidrug resistance-associated protein involved in anthocyanin transport in Zea mays
A multidrug resistance-associated protein involved in anthocyanin transport in Zea mays
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DOI：
10.1105/tpc.022574
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发表时间：
2004-07-01
期刊：
影响因子：
11.6
通讯作者：
Walbot, V
中科院分区：
文献类型：
--
作者：
Goodman, CD;Casati, P;Walbot, V
花色素苷合成是生物学中研究最深入的酶途径之一，但对其最后阶段的分子机制知之甚少：花色素苷色素运输到液泡中。我们已经确定了一个多药耐药相关蛋白（MRP），ZmMrp3，这是需要在玉米（玉米）的运输过程。ZmMrp3的表达受花青素苷生物合成调控因子的控制，并反映了其他花青素苷结构基因的表达。ZmMRP3在体内的定位显示其存在于液泡膜中，在该位点处发生花色素苷转运。使用反义构建体产生的突变体在成年植物中具有独特的色素沉着表型，这是由于色素的错误定位以及花青素苷含量的显著降低，而所产生的花青素苷种类没有改变。令人惊讶的是，突变体植物在糊粉层中没有表现出表型。这似乎反映了第二个高度同源的基因ZmMrp4的存在，该基因也与花青素途径共调节，但仅在糊粉层组织中表达。这种描述的植物MRP与运输的一个已知的内源性底物的作用提供了一个新的模型系统，用于检查参与MRP介导的植物次生代谢产物的运输的生物和生化机制。
Anthocyanin biosynthesis is one of the most thoroughly studied enzymatic pathways in biology, but little is known about the molecular mechanisms of its final stage: the transport of the anthocyanin pigment into the vacuole. We have identified a multidrug resistance-associated protein (MRP), ZmMrp3, that is required for this transport process in maize (Zea mays). ZmMrp3 expression is controlled by the regulators of anthocyanin biosynthesis and mirrors the expression of other anthocyanin structural genes. Localization of ZmMRP3 in vivo shows its presence in the tonoplast, the site at which anthocyanin transport occurs. Mutants generated using antisense constructs have a distinct pigmentation phenotype in the adult plant that results from a mislocalization of the pigment as well as significant reduction in anthocyanin content, with no alteration in the anthocyanin species produced. Surprisingly, mutant plants did not show a phenotype in the aleurone. This appears to reflect the presence of a second, highly homologous gene, ZmMrp4, that is also coregulated with the anthocyanin pathway but is expressed exclusively in aleurone tissue. This description of a plant MRP with a role in the transport of a known endogenous substrate provides a new model system for examining the biological and biochemical mechanisms involved in the MRP-mediated transport of plant secondary metabolites.