Qin GJ, Gu HY, Zhao YD, Ma ZQ, Shi GL, Yang Y, Pichersky E, Chen HD, Liu MH, Chen ZL, Qu L-J*, An indole-3-acetic acid carboxyl methyltransferase regulates Arabidopsis leaf development. PLANT CELL, 17: 2693-2704, 2005.

Abstract Auxin is central to many aspects of plant development; accordingly, plants have evolved several mechanisms to regulate auxin levels, including de novo auxin biosynthesis, degradation, and conjugation to sugars and amino acids. Here, we report the characterization of an Arabidopsis thaliana mutant, IAA carboxyl methyltransferase1-dominant (iamt1-D), which displayed dramatic hyponastic leaf phenotypes caused by increased expression levels of the IAMT1 gene. IAMT1 encodes an indole-3-acetic acid (IAA) carboxyl methyltransferase that converts IAA to methyl-IAA ester (MeIAA) in vitro, suggesting that methylation of IAA plays an important role in regulating plant development and auxin homeostasis. Whereas both exogenous IAA and MeIAA inhibited primary root and hypocotyl elongation, MeI......