Impact of UGT80B1 absence on Arabidopsis thaliana growth under salt stress

Abstract

Sterol glycosylation, facilitated by sterol UDP-glycosyltransferases (SGTs), plays a crucial
role in various biological functions, influencing cellular homeostasis, lipid metabolism, water
solubility, molecule stability, and the properties of cell membranes for improved transport
system access and stress tolerance. In the model plant Arabidopsis thaliana (A. thaliana), two
sterol β-glucosyltransferase genes within the UGT80 subfamily, UGT80B1 (At1g43620) and
UGT80A2 (At3g07020), are responsible for catalyzing the glycosylation of the 3β-hydroxy
group of sterols, resulting in the formation of 3β-D-glycosides.Analysis of knockout mutants
for both genes, particularly salk-021175 (Atg43620 gene), revealed a moderate impact on
growth under normal conditions, with a distinctive transparent seed coat compared to other
genotypes. However, under salt stress, this knockout mutant exhibited significant adverse
effects on overall plant growth, physiological activities, and enzyme functions compared to
other genotypes. The relative expression of AtSGTs under salt stress, along with chlorophyll
fluorescence analysis, emphasized the crucial role of the Atg43620 gene in both normal plant
growth and stress responses. Overall, the findings underscore the importance of sterol
glycosylation, particularly mediated by the Atg43620 gene, in shaping plant physiology and
enhancing stress tolerance.