The use of abscisic acid analogues to analyse the substrate selectivity of UGT71B6, a UDP‐glycosyltransferase of Arabidopsis thaliana

Abstract

This study analyses the activity of an Arabidopsis thaliana UDP-glycosyltransferase, UGT71B6 (71B6), towards abscisic acid (ABA) and its structural analogues. The enzyme preferentially glucosylated ABA and not its catabolites. The requirement for a specific chiral configuration of (+)-ABA was demonstrated through the use of analogues with the chiral centre changed or removed. The enzyme was able to accommodate extra bulk around the double bond of the ABA ring but not alterations to the 8 0 -and 9 0 -methyl groups. Interestingly, the ketone of ABA was not required for glucosylation. Bioactive analogues, resistant to 8 0 -hydroxylation, were also poor substrates for conjugation by UGT71B6. This suggests the compounds may be resistant to both pathways of ABA inactivation and may, therefore, prove to be useful agrochemicals for field applications.

Transcription Analysis of Arabidopsis Membrane Transporters and Hormone Pathways during Developmental and Induced Leaf Senescence

“…10, A-D). On the other hand, the ABAinactivating glucosylase UGT71B6 (Priest et al, 2005) is also up-regulated during NS (Supplemental Fig. 10E).…”

Arabidopsis Defense against Botrytis cinerea: Chronology and Regulation Deciphered by High-Resolution Temporal Transcriptomic Analysis

“…ABA catabolism is overrepresented in the group of genes first differentially expressed 20 HAI due to the upregulation of CYP707A3 and UGT71B6. CYP707A3 catalyzes both 89-and 99-hydroxylation of ABA, with 89-hydroxylation being the major pathway of ABA catabolism (Saito et al, 2004;Okamoto et al, 2011), while UGT71B6 glycosylates ABA to supposedly inactive conjugates (Priest et al, 2005). Two hours later (22 HAI) upregulation of negative regulators of ABA signaling begins.…”

Abscisic acid metabolism and lipid accumulation of a cell suspension culture of Lesquerella fendleri

“…It is known that (+)-ABA can be catabolized through various pathways, the preference for which depends on the plant species, plant part, different physiological conditions and the plant developmental stage (Balsevich et al, 1994;Zhou et al, 2004;Zaharia et al, 2005a). The catabolism of (+)-ABA occurs through oxidation and reduction or conjugation to glucose (Priest et al, 2005). The major oxidation/reduction pathway occurs through hydroxylation of the 8 -methyl group of ABA, leading to the formation of the intermediate product (+)-8 -hydroxy ABA which furthers rearranges to phaseic acid (PA) (Zou et al, 1995;Zhou et al, 2004).…”