Cytosolic- and membrane-localized oxidized indole-3-acetic acid formation regulates developmental auxin transients.

ABSTRACT: Catabolism of the auxin indole-3-acetic acid (IAA) to terminate cellular responses primarily occurs in three steps: (i) conjugation of IAA to Asp/Glu, (ii) oxidation of the indole ring by DIOXYGENASE FOR AUXIN OXIDATION (DAO), and (iii) amidohydrolase cleavage of Asp/Glu. This study examines if IAA oxidation historically associated with membranes is mediated by DAO isoforms and if the oxidized auxin product (oxIAA) retains nominal functionality. We show that Arabidopsis thaliana DAO1 exhibits both soluble and auxin-dependent plasma membrane association, and that oxIAA exhibits weak "anti-auxin" activity. Both soluble and membrane-associated DAO1 primarily oxidized IAAsp. DAO2 activity was enzymatically similar to DAO1 and occurred where IAA levels were high. DAO1 and DAO2 functioned synerg

SUBMITTER: Jenness M 

PROVIDER: S-EPMC12344411 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature