Chlorinated Auxins-How Does Arabidopsis Thaliana Deal with Them?
Chlorinated Auxins-How Does Arabidopsis Thaliana Deal with Them?
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DOI：
10.3390/ijms21072567
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发表时间：
2020-04-01
影响因子：
5.6
通讯作者：
Ludwig-Mueller, Jutta
中科院分区：
文献类型：
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作者：
Walter, Antje;Caputi, Lorenzo;Ludwig-Mueller, Jutta
植物激素在植物体内具有多种功能，在植物的各个发育和分化阶段都起着至关重要的作用。甜菜碱是甜菜碱中最重要的一类，其主要代表物是吲哚-3-乙酸（IAA）。4-氯吲哚-3-乙酸（4-Cl-IAA）是IAA的卤代衍生物，以前曾在豌豆和其他豆类中发现。虽然在细菌和真菌中负责化合物卤化的酶已被充分研究，但在植物中导致4-Cl-IAA产生的代谢途径，特别是卤化反应，仍然是未知的。因此，将细菌黄素依赖性色氨酸卤化酶基因转化到模式生物拟南芥中。通过孵育野生型A来确定可预期的氯化吲哚衍生物的类型。thaliana与不同的Cl-色氨酸衍生物。我们表明，除了氯化IAA，氯化IAA共轭物合成。同时，我们发现A. thaliana能够在体外将氯化的IAAs转化为氨基酸缀合物。此外，我们还证明了转基因拟南芥中可能产生卤代色氨酸（Trp）、吲哚乙腈（IAN）和IAA。在细菌卤化酶的帮助下，此外，研究了（i）外源施用的Cl-IAA和Cl-Trp和（ii）内源氯化物质对植物生长表型的影响。
Plant hormones have various functions in plants and play crucial roles in all developmental and differentiation stages. Auxins constitute one of the most important groups with the major representative indole-3-acetic acid (IAA). A halogenated derivate of IAA, 4-chloro-indole-3-acetic acid (4-Cl-IAA), has previously been identified in Pisum sativum and other legumes. While the enzymes responsible for the halogenation of compounds in bacteria and fungi are well studied, the metabolic pathways leading to the production of 4-Cl-IAA in plants, especially the halogenating reaction, are still unknown. Therefore, bacterial flavin-dependent tryptophan-halogenase genes were transformed into the model organism Arabidopsis thaliana. The type of chlorinated indole derivatives that could be expected was determined by incubating wild type A. thaliana with different Cl-tryptophan derivatives. We showed that, in addition to chlorinated IAA, chlorinated IAA conjugates were synthesized. Concomitantly, we found that an auxin conjugate synthetase (GH3.3 protein) from A. thaliana was able to convert chlorinated IAAs to amino acid conjugates in vitro. In addition, we showed that the production of halogenated tryptophan (Trp), indole-3-acetonitrile (IAN) and IAA is possible in transgenic A. thaliana in planta with the help of the bacterial halogenating enzymes. Furthermore, it was investigated if there is an effect (i) of exogenously applied Cl-IAA and Cl-Trp and (ii) of endogenously chlorinated substances on the growth phenotype of the plants.