College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Int J Mol Sci. 2023 May 10;24(10):8514. doi: 10.3390/ijms24108514.
The indole-3-pyruvic acid (IPA) pathway is the main auxin biosynthesis pathway in the plant kingdom. Local control of auxin biosynthesis through this pathway regulates plant growth and development and the responses to biotic and abiotic stresses. During the past decades, genetic, physiological, biochemical, and molecular studies have greatly advanced our understanding of tryptophan-dependent auxin biosynthesis. The IPA pathway includes two steps: Trp is converted to IPA by TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS/TRYPTOPHAN AMINOTRANSFERASE RELATED PROTEINs (TAA1/TARs), and then IPA is converted to IAA by the flavin monooxygenases (YUCCAs). The IPA pathway is regulated at multiple levels, including transcriptional and post-transcriptional regulation, protein modification, and feedback regulation, resulting in changes in gene transcription, enzyme activity and protein localization. Ongoing research indicates that tissue-specific DNA methylation and miRNA-directed regulation of transcription factors may also play key roles in the precise regulation of IPA-dependent auxin biosynthesis in plants. This review will mainly summarize the regulatory mechanisms of the IPA pathway and address the many unresolved questions regarding this auxin biosynthesis pathway in plants.
色氨酸-3-丙酮酸（IPA）途径是植物王国中主要的生长素生物合成途径。通过该途径对生长素生物合成进行局部控制，调节植物生长发育以及对生物和非生物胁迫的响应。在过去的几十年中，遗传、生理、生化和分子研究极大地促进了我们对依赖色氨酸的生长素生物合成的理解。IPA 途径包括两步：色氨酸被色氨酸氨基转移酶/色氨酸氨基转移酶相关蛋白（TAA1/TARs）转化为 IPA，然后 IPA 被黄素单加氧酶（YUCCAs）转化为 IAA。IPA 途径在多个水平上受到调节，包括转录和转录后调节、蛋白质修饰和反馈调节，导致基因转录、酶活性和蛋白质定位的变化。正在进行的研究表明，组织特异性 DNA 甲基化和 miRNA 介导的转录因子调控可能在植物中 IPA 依赖的生长素生物合成的精确调控中也发挥着关键作用。本综述将主要总结 IPA 途径的调控机制，并解决植物中生长素生物合成途径的许多未解问题。
