auxin-metabolism
Auxin metabolism encompasses the biosynthesis, conjugation, transport, and degradation pathways that regulate the levels and activity of auxin, a key plant hormone. Precise control of auxin availability governs essential processes such as cell elongation, tissue differentiation, and tropic growth responses to light and gravity. Understanding these metabolic pathways provides insight into how plants coordinate growth and development at both the cellular and whole-organism level.
open_in_new WikipediaPubMed · 2026-06-19
Plants use special enzymes to deactivate the growth hormone auxin by attaching different amino acids to it. This study shows that two families of these enzymes have distinct preferences — one favors aspartate, the other glutamine — a division that is conserved across plant species.
NtGH3.1a (and its Arabidopsis counterpart AtGH3.1) preferentially conjugates auxin (IAA) with aspartate, producing IAA-Asp as the main inactivation product.
NtGH3.6e (and Arabidopsis AtGH3.5/6) preferentially conjugates auxin with glutamine, producing the less-studied conjugates IAA-Gln and oxIAA-Gln.
Both enzyme types localize to the nucleus and cytoplasm regardless of auxin levels, suggesting their distribution is not dynamically regulated by the hormone they inactivate.
