Functional complementation of anthocyanin sequestration in the vacuole by widely divergent glutathione S-transferases
Functional complementation of anthocyanin sequestration in the vacuole by widely divergent glutathione S-transferases
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DOI：
10.1105/tpc.10.7.1135
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发表时间：
1998-07-01
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：
Alfenito, MR;Souer, E;Walbot, V
传统上已经在植物和其他生物体中研究了谷胱甘肽S-转移酶（GST），因为它们能够解毒化学上不同的除草剂和其他有毒有机化合物。花色素苷是少数已被鉴定的植物GST的内源底物之一。Bronze 2（Bz 2）基因编码III型GST，并执行玉米花青素色素途径的最后一个遗传定义步骤。该步骤是谷胱甘肽与矢车菊素3-葡萄糖苷（C3 G）的缀合。谷胱甘肽C3 G通过液泡膜Mg-ATP-需要谷胱甘肽泵（GS-X泵）运输到液泡。遗传上，矮牵牛花色素苷途径中的可比步骤由花色素苷9（An 9）基因控制。An 9是通过转座子标签法克隆的，并被发现编码I型植物GST，Bz 2和An 9是从不同类型的GST独立进化而来的，但每个都受到花青素途径的保守转录激活因子的调控。在这里，提出了系统发育分析，特别考虑到这些基因的起源和放宽基板的要求。在粒子轰击试验中，An 9和Bz 2在功能上互补两种突变体。在测试的几种其他GST中，发现仅大豆GmGST 26 A（以前称为GmHsp 26 A和GH 2/4）和玉米GSTIII赋予花色素苷的液泡隔离。以前，这些基因与花青素途径无关。通过对an 9-T3529、bz 2：：Ds和bz 2：：Mu 1的功能性和非功能性germ回复突变体进行测序，研究了对An 9和Bz 2基因功能的要求。
Glutathione S-transferases (GSTs) traditionally have been studied in plants and other organisms for their ability to detoxify chemically diverse herbicides and other toxic organic compounds. Anthocyanins are among the few endogenous substrates of plant GSTs that have been identified. The Bronze2 (Bz2) gene encodes a type III GST and performs the last genetically defined step of the maize anthocyanin pigment pathway. This step is the conjugation of glutathione to cyanidin 3-glucoside (C3G). Glutathionated C3G is transported to the vacuole via a tonoplast Mg-ATP-requiring glutathione pump (GS-X pump). Genetically, the comparable step in the petunia anthocyanin pathway is controlled by the Anthocyanin9 (An9) gene. An9 was cloned by transposon tagging and found to encode a type I plant GST, Bz2 and An9 have evolved independently from distinct types of GSTs, but each is regulated by the conserved transcriptional activators of the anthocyanin pathway. Here, a phylogenetic analysis is presented, with special consideration given to the origin of these genes and their relaxed substrate requirements. In particle bombardment tests, An9 and Bz2 functionally complement both mutants. Among several other GSTs tested, only soybean GmGST26A (previously called GmHsp26A and GH2/4) and maize GSTIII were found to confer vacuolar sequestration of anthocyanin. Previously, these genes had not been associated with the anthocyanin pathway. Requirements for An9 and Bz2 gene function were investigated by sequencing functional and nonfunctional germinal revertants of an9-T3529, bz2::Ds, and bz2::Mu1.