期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2009
卷号：106
期号：34
页码：14699-14704
DOI：10.1073/pnas.0905434106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A previously undescribed forward chemical genetic screen using hydrolases affecting the extracellular matrix is introduced. The developed screen takes advantage of the power of chemical genetics and combines it with the known substrate specificity of glycosylhydrolases, resulting in the selection of conditional mutants that exhibit structural defects in their extracellular matrix. Identification of the responsible genetic locus in those mutants significantly extends our knowledge of genes involved in the biosynthesis, metabolism, signaling, and functionality of components of the extracellular matrix. The method is exemplified by a screen of mutagenized Arabidopsis plants subjected to growth in liquid culture in the presence of a xyloglucanase, an enzyme acting on the major cross-linking glycan found in the extracellular matrix of this plant. Using this hydrolase-based screen, dozens of plant cell wall mutants (xeg mutants) were identified, leading to the identification of 23 genetic loci that affect plant cell walls. One of the identified loci is XEG113, encoding a family 77 glycosyltransferase (GT77). Detailed analysis of the wall of this mutant indicated that its extensins, structural glyocoproteins present in walls, are underarabinosylated. Xeg-113 plants exhibit more elongated hypocotyls than WT, providing genetic evidence that plant O-glycosylation--more specifically, extensin arabinosylation--is important for cell elongation.
