Genome-wide investigation of family‑1 UDP glycosyltransferases reveals the Fusarium resistance role of VfUGT90A2 in tung trees

Abstract

UDP-glycosyltransferases (UGTs) play vital roles in pathogen resistance through secondary metabolites, such as flavonoid. Vernicia fordii (tung trees) is well known for its production of industrial oil, which has been decimated by the soil-borne fungus Fusarium oxysporum f. sp. Fordiis (Fof-1). The current understanding of the metabolic and molecular mechanism of V. fordii against Fof-1 is limited. Through genome-wide analysis identified 153 VfUGTs, which were divided into 16 clusters derived from tandem and segmental repeat events. Variations in gene structure and cis-elements have contributed to gene differentiation within the various subfamilies of VfUGTs. VfUGT90A2 was found to be highly induced and expressed, serving as a key gene during the response process to Fof-1 infection in tree roots. The study showed that transgenic hairy roots of the tung trees, overexpressing VfUGT90A2, displayed significantly enhanced resistance to Fof-1. Additionally, the root extract from these transgenic roots was found to have a notable inhibitory effect on the growth of Fof-1 mycelium. Metabolomic and transcriptomic analyses further revealed an increase in flavonoids, such as quercitrin and myricitrin, in the transgenic hairy roots overexpressing VfUGT90A2. Meanwhile, VfUGT90A2 was speculated bound well to quercetin by protein docking predictions. The enzyme activity assay in vitro further verified that VfUGT90A2 catalyzed the glycosylation of quercetin. In all, our data shows that VfUGT90A2 is involved in the flavonoid biosynthetic pathways and has an impact on enhancing the resistance of plant to Fusarium, therefore, offers an opportunity to explore an effective strategy for Fusarium resistant plant breeding.