Identification and functional characterization of novel plant UDP-glycosyltransferase (LbUGT72B10) for the bioremediation of 3,4-dichloroaniline

Herbicides are chemicals used to manipulate or control the growth of undesired plants and thereby protect crops. However, they and their degradation products can persist and accumulate in the environment, leading to contamination of soil and water systems and biodiversity loss. Interestingly, through the action of UDP-glycosyltransferases (UGTs), higher plants can glycosylate these xenobiotics, increasing their solubility and alleviating their toxicity. Here, seven plant UGTs belonging to family 72 of the UGT nomenclature were identified to N-glycosylate 3,4-dichloroaniline (3,4-DCA), which is a degradation product of commercially significant herbicides like Diuron, Linuron and Propanil. Although chlorinated chemicals are well-known UGT substrates, only one UGT with activity on 3,4-DCA (AtUGT72B1 from Arabidopsis thaliana) has been fully biochemically characterized. In this study, biochemical analysis revealed that six of the seven identified UGTs are capable of full conversion of 3,4-DCA to its N-glucoside. The most efficient enzyme was found to be LbUGT72B10 from Lycium barbarum (kcat = 11.2 s−1, KM = 51.2 μM). Consequently, transgenic expression of LbUGT72B10 could potentially play a role in the future in the mitigation of 3,4-DCA toxicity, preventing its accumulation in living systems and reducing contamination of waterways and soil.