Regulation of Auxin Homeostasis and Gradients in Arabidopsis Roots through the Formation of the Indole-3-Acetic Acid Catabolite 2-Oxindole-3-Acetic Acid

作者：Aleš Pěnčík, Biljana Simonovik, Sara V. Petersson, Eva Hényková, Sibu Simon, Kathleen Greenham, Yi Zhang, Mariusz Kowalczyk, Mark Estelle, Eva Zažı́malová, Ondřej Novák, Göran Sandberg, Karin Ljung · 发表于：The Plant Cell · 年份：2013 · DOI：10.1105/tpc.113.114421 · 被引用次数：140 · 研究领域：Plant Molecular Biology Research、Plant Gene Expression Analysis、Plant nutrient uptake and metabolism

The native auxin, indole-3-acetic acid (IAA), is a major regulator of plant growth and development. Its nonuniform distribution between cells and tissues underlies the spatiotemporal coordination of many developmental events and responses to environmental stimuli. The regulation of auxin gradients and the formation of auxin maxima/minima most likely involve the regulation of both metabolic and transport processes. In this article, we have demonstrated that 2-oxindole-3-acetic acid (oxIAA) is a major primary IAA catabolite formed in Arabidopsis thaliana root tissues. OxIAA had little biological activity and was formed rapidly and irreversibly in response to increases in auxin levels. We further showed that there is cell type-specific regulation of oxIAA levels in the Arabidopsis root apex. We propose that oxIAA is an important element in the regulation of output from auxin gradients and, therefore, in the regulation of auxin homeostasis and response mechanisms.