Identification and Biochemical Characterization of anArabidopsis Indole-3-acetic Acid Glucosyltransferase*
Abstract
Biochemical characterization of recombinant gene products following a phylogenetic analysis of the UDP-glucosyltransferase (UGT) multigene family ofArabidopsis has identified one enzyme (UGT84B1) with high activity toward the plant hormone indole-3-acetic acid (IAA) and three related enzymes (UGT84B2, UGT75B1, and UGT75B2) with trace activities. The identity of the IAA conjugate has been confirmed to be 1-O-indole acetyl glucose ester. A sequence annotated as a UDP-glucose:IAA glucosyltransferase (IAA-UGT) in theArabidopsis genome and expressed sequence tag data bases given its similarity to the maize iaglu gene sequence showed no activity toward IAA. This study describes the first biochemical analysis of a recombinant IAA-UGT and provides the foundation for future genetic approaches to understand the role of 1-O-indole acetyl glucose ester inArabidopsis.
- UGT
- UDP-glucosyltransferase
- GST
- glutathione S-transferase
- PAGE
- polyacrylamide gel electrophoresis
- PCR
- polymerase chain reaction
- RT-PCR
- reverse transcription-PCR
- UDPG
- uridine-5′-diphosphoglucose
- HPLC
- high performance liquid chromatography
- IBA
- indole butyric acid
- IPA
- indole propionic acid
- NAA
- naphthaleneacetic acid
- IAGlc
- 1-O-indole acetyl glucose ester
- IAA
- indole-3-acetic acid
- Received July 13, 2000.
- Revision received September 25, 2000.
- The American Society for Biochemistry and Molecular Biology, Inc.
