Premium
Identification and characterization of the BAHD acyltransferase malonyl CoA: Anthocyanidin 5‐ O ‐glucoside‐6″‐ O ‐malonyltransferase (At5MAT) in Arabidopsis thaliana
Author(s) -
D’Auria John C.,
Reichelt Michael,
Luck Katrin,
Svatoš Aleš,
Gershenzon Jonathan
Publication year - 2007
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2007.01.060
Subject(s) - acyltransferase , anthocyanin , arabidopsis thaliana , biochemistry , glucosyltransferase , glycosylation , anthocyanidin , biology , chemistry , mutant , glucoside , gene , botany , medicine , alternative medicine , pathology
The major anthocyanin in A. thaliana is a cyanidin derivative modified by glycosylation as well as by the addition of three acyl moieties: malonyl, p ‐coumaroyl, and sinapoyl. We have isolated a member of the BAHD acyltransferase family which catalyzes this malonylation reaction by combining a reverse genetics approach with biochemical genomics. A mutant line containing a T‐DNA insertion in At3g29590 , the gene encoding the malonylating enzyme, is incapable of producing malonylated anthocyanins. Transgenic plants harboring an RNAi silencing cassette for At3g29590 demonstrate a positive correlation between reduction in the At3g29590 gene transcript and the decrease of malonylated anthocyanins. Transcript levels for both At3g29590 and the epistatic gene At4g14090 , encoding 5‐ O ‐anthocyanin glucosyltransferase, increase in several plant lines as they accumulate anthocyanin pigments. Investigation of the heterologously expressed and purified malonylating enzyme showed that the activity is specific for malonyl‐CoA and for anthocyanins with 5‐ O ‐glucosylation. The malonyl transfer itself occurs only to the 5‐ O ‐glucoside function, and not to any of the other sugar moieties present in A. thaliana anthocyanins. Hence, both in vivo and in vitro results define the activity of the At3g29590‐encoded enzyme as an anthocyanin 5‐ O ‐glucoside‐6″‐ O ‐malonyltransferase (At5MAT).