Overexpression of UDP-glycosyltransferase genes enhanced aluminum tolerance through disrupting cell wall polysaccharide components in soybean.

Purpose: Plant cell wall polysaccharide composition is closely related to the occurrence of aluminum (Al) toxicity and Al resistance. Glycosyltransferases participate in cell wall polysaccharide biosynthesis. Our previous microarray analysis showed that Al increased the transcriptional abundance of UDP-glycosyltransferase (UGT) in soybean (Glycine max). The present study aimed to clarify if GmUGTs are involved in modifying the composition of cell wall polysaccharides and then alter soybean Al sensitivity. Methods: Two soybean genes, UGT85A111 and UGT83R1, were identified, and their functions were characterized by analyses of expression pattern and subcellular localization, and evaluations of carbohydrates in the cell wall and Al sensitivity by their overexpression in soybean hairy roots and Arabidopsis. Results: The transcriptional expression of UGT85A111 and UGT83R1 was increased with different patterns and levels under Al stress. Both GmUGTs localized to the plasma membrane. UGT85A111-OE and UGT83R1-OE soybean hairy roots showed less Al absorption, which was accompanied by alterations in cell wall polysaccharide components, particularly reduced callose and/or hemicellulose contents. Monosaccharide content, including glucose and xylose in the GmUGTs-OE roots, was also affected. Heterologous expression of UGT85A111 and UGT83R1 significantly improved the plant's Al resistance capacity. Conclusion: GmUGTs contribute to the disruption of cell wall polysaccharide compositions and Al sensitivity in soybean. The results suggest a particularly protective role of UGTs against Al toxicity and may provide novel clues for plant Al stress adaptation. [ABSTRACT FROM AUTHOR]