title: LEW3, encoding a putative alpha-1,2-mannosyltransferase (ALG11) in N-linked glycoprotein, plays vital roles in cell-wall biosynthesis and the abiotic stress response in Arabidopsis thaliana.
abstract: N-linked glycosylation is an essential protein modification that helps protein folding, trafficking and translocation in eukaryotic systems. The initial process for N-linked glycosylation shares a common pathway with assembly of a dolichol-linked core oligosaccharide. Here we characterize a new Arabidopsis thaliana mutant lew3 (leaf wilting 3), which has a defect in an alpha-1,2-mannosyltransferase, a homolog of ALG11 in yeast, that transfers mannose to the dolichol-linked core oligosaccharide in the last two steps on the cytosolic face of the ER in N-glycan precursor synthesis. LEW3 is localized to the ER membrane and expressed throughout the plant. Mutation of LEW3 caused low-level accumulation of Man(3)GlcNAc(2) and Man(4)GlcNAc(2) glycans, structures that are seldom detected in wild-type plants. In addition, the lew3 mutant has low levels of normal high-mannose-type glycans, but increased levels of complex-type glycans. The lew3 mutant showed abnormal developmental phenotypes, reduced fertility, impaired cellulose synthesis, abnormal primary cell walls, and xylem collapse due to disturbance of the secondary cell walls. lew3 mutants were more sensitive to osmotic stress and abscisic acid (ABA) treatment. Protein N-glycosylation was reduced and the unfolded protein response was more activated by osmotic stress and ABA treatment in the lew3 mutant than in the wild-type. These results demonstrate that protein N-glycosylation plays crucial roles in plant development and the response to abiotic stresses.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Maurice
authors.initials: M
authors.lastname: Henquet
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Chen
authors.forename: Hairong
authors.initials: H
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaozhi
authors.initials: X
authors.lastname: Ren
authors.forename: Sander
authors.initials: S
authors.lastname: van der Krol
authors.forename: Martine
authors.initials: M
authors.lastname: Gonneau
authors.forename: Dirk
authors.initials: D
authors.lastname: Bosch
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Gong
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D002482:Cellulose / Q000096:biosynthesis; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D020043:Genes, Essential; D005816:Genetic Complementation Test; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006031:Glycosylation; D008364:Mannosyltransferases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D018526:Plant Transpiration; D011401:Promoter Regions, Genetic; D018749:RNA, Plant / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D056811:Unfolded Protein Response; D052584:Xylem / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D006023:Glycoproteins; D018749:RNA, Plant; D012965:Sodium Chloride; D002482:Cellulose; D008364:Mannosyltransferases