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.

中文翻译：

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UDP-糖基转移酶基因的过表达通过破坏大豆细胞壁多糖成分增强铝耐受性

目的

植物细胞壁多糖的组成与铝（Al）毒性和抗铝性的发生密切相关。糖基转移酶参与细胞壁多糖生物合成。我们之前的微阵列分析表明，Al 增加了大豆 ( Glycine max )中 UDP-糖基转移酶 (UGT) 的转录丰度。本研究旨在阐明 GmUGT 是否参与改变细胞壁多糖的组成，进而改变大豆对铝的敏感性。

方法

鉴定了两个大豆基因UGT85A111和UGT83R1，它们的功能通过表达模式和亚细胞定位的分析以及细胞壁中碳水化合物的评估和通过它们在大豆毛根和拟南芥中的过度表达来评估铝敏感性来表征。

结果

UGT85A111和UGT83R1的转录表达在铝胁迫下以不同的模式和水平增加。两种 GmUGT 均定位于质膜。UGT85A111 -OE 和UGT83R1 -OE 大豆毛状根表现出较少的铝吸收，伴随着细胞壁多糖成分的改变，特别是胼胝质和/或半纤维素含量降低。单糖含量，包括GmUGTs -OE 根中的葡萄糖和木糖，也受到影响。UGT85A111和UGT83R1的异源表达显着提高了植物的抗铝能力。

结论

GmUGT 有助于破坏大豆细胞壁多糖组成和铝敏感性。结果表明 UGT 对铝毒性具有特别的保护作用，并可能为植物铝胁迫适应提供新的线索。