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. 2021 Mar;13(3):a039867. doi: 10.1101/cshperspect.a039867

Figure 1.

Figure 1.

Main pathways for indole-3-acetic acid (IAA) metabolism in plants. Biosynthesis of the IAA precursor l-tryptophan (Trp) takes place in the plastid (green oval). Subsequent IAA biosynthesis, catabolism, and conjugation reactions commonly operate in the cytoplasm. IAA molecules are indicated as red hexagons and IAA-related metabolites are shown in black. Enzymes catalyzing the metabolic reactions are indicated in purple. Major components for IAA biosynthesis and inactivation are indicated with red arrows. Solid arrows indicate pathways in which the enzymes, genes, or intermediates are known, while dashed arrows indicate pathways that are not yet well defined. Brassica-specific metabolites are indicated in orange. Green cylinders indicate intracellular IAA transporters and the attached arrows indicate the IAA movement direction. The blue circle, the gray oval, and the pale orange square indicate peroxisome, nucleus, and vacuole, respectively. Endoplasmic reticulum (ER) is indicated by the dark yellow structure attached to the nucleus. Organelles are not drawn to scale. (AMI1) AMIDASE-LIKE PROTEIN 1, (ANT) anthranilate, (ASA1) ANTHRANILATE SYNTHASE α SUBUNIT 1, (ASB1) ANTHRANILATE SYNTHASE β SUBUNIT 1, (CYP79B2/B3) CYTOCHROME P450, family 79, subfamily B, polypeptides 2 and 3, (DAO) DIOXYGENASE FOR AUXIN OXIDATION, (GH3) GRETCHEN HAGEN3, (IAA-glc) IAA-glucose, (IAM) indole-3-acetamide, (IAMT1) indole-3-acetate O-methyltransferase 1, (IAN) indole-3-acetonitrile, (IAOx) indole-3-acetaldoxime, (IBA) indole-3-butyric acid, (IAR3) IAA-ALANINE RESISTANT3, (ILLs) ILR1-LIKE, (ILR1) IAA-LEUCINE RESISTANT1, (IPyA) indole-3-pyruvic acid, (meIAA) methylindole-3-acetic acid, (MES17) METHYLESTERASE 17, (oxIAA) 2-oxindole-3-acetic acid, (Phe) phenylalanine, (PILS) PIN-likes, (PIN) PIN-FORMED, (TAA1) TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1, (TAR) TRYPTOPHAN AMINOTRANSFERASE-RELATED PROTEIN, (Trp-AT) TRYPTOPHAN AMINOTRANSFERASE, (UGTs) URIDINE-DIPHOSPHATE GLYCOSYLTRANSFERASE, (VAS1) REVERSAL OF SAV3 PHENOTYPE 1, (WAT1) WALLS ARE THIN1, (YUC) YUCCA flavin-containing monooxygenases.