Arabidopsis GT34 family contains five xyloglucan alpha-1,6-xylosyltransferases

作者：Vuttipongchaikij Supachai; Brocklehurst David; Steele King Clare; Ashford David A; Gomez Leonardo D; McQueen Mason Simon J^*

来源：New Phytologist, 2012, 195(3): 585-595.

DOI：10.1111/j.1469-8137.2012.04196.x

• Arabidopsis
• cell wall biosynthesis
• galactomannan
• glycosyltransferase
• plant cell walls
• xyloglucan

The Arabidopsis genome includes seven family 34 glycosyltransferase (GT34) encoding genes. XXT1 and XXT2 have previously been shown to encode XyG a-1,6-xylosyltransferases, while knockout mutants of a third, XXT5, exhibit decreased XyG content, suggesting a similar activity. Here, we extend the study to the rest of the Arabidopsis GT34 genes in terms of biochemical activity and their roles in XyG biosynthesis. The enzyme activity of XXTs was investigated using recombinant protein expressed in E.similar to coli. XyG analysis of single and double T-DNA insertion knockouts, together with overexpression of GT34s in selected mutant lines, provided detailed function of each gene. We reveal the activity of the third member of the GT34 gene family (XXT4) that exhibits xylosyltransferase activity. Double mutants for either xxt2 or xxt5 had a large impact on XyG content, structure and size distribution. Overexpression of the remaining member, XXT3, was able to restore XyG epitopes in xxt2, xxt5 and xxt2 xxt5 double knockouts, suggesting that it also encodes a protein with XXT activity. Our work demonstrates that five of the seven Arabidopsis GT34 genes encode XXT enzymes.

• 出版日期2012-8