RRC ID 37114
Author Basu D, Wang W, Ma S, DeBrosse T, Poirier E, Emch K, Soukup E, Tian L, Showalter AM.
Title Two Hydroxyproline Galactosyltransferases, GALT5 and GALT2, Function in Arabinogalactan-Protein Glycosylation, Growth and Development in Arabidopsis.
Journal PLoS ONE
Abstract Hydroxyproline-O-galactosyltransferase (GALT) initiates O-glycosylation of arabinogalactan-proteins (AGPs). We previously characterized GALT2 (At4g21060), and now report on functional characterization of GALT5 (At1g74800). GALT5 was identified using heterologous expression in Pichia and an in vitro GALT assay. Product characterization showed GALT5 specifically adds galactose to hydroxyproline in AGP protein backbones. Functions of GALT2 and GALT5 were elucidated by phenotypic analysis of single and double mutant plants. Allelic galt5 and galt2 mutants, and particularly galt2 galt5 double mutants, demonstrated lower GALT activities and reductions in β-Yariv-precipitated AGPs compared to wild type. Mutant plants showed pleiotropic growth and development phenotypes (defects in root hair growth, root elongation, pollen tube growth, flowering time, leaf development, silique length, and inflorescence growth), which were most severe in the double mutants. Conditional mutant phenotypes were also observed, including salt-hypersensitive root growth and root tip swelling as well as reduced inhibition of pollen tube growth and root growth in response to β-Yariv reagent. These mutants also phenocopy mutants for an AGP, SOS5, and two cell wall receptor-like kinases, FEI1 and FEI2, which exist in a genetic signaling pathway. In summary, GALT5 and GALT2 function as redundant GALTs that control AGP O-glycosylation, which is essential for normal growth and development.
Volume 10(5)
Pages e0125624
Published 2015
DOI 10.1371/journal.pone.0125624
PII PONE-D-14-56565
PMID 25974423
PMC PMC4431829
MeSH Adenosine Diphosphate / metabolism Arabidopsis / genetics* Arabidopsis / growth & development Arabidopsis / metabolism Arabidopsis Proteins / genetics* Arabidopsis Proteins / metabolism Flowers / genetics Flowers / growth & development Flowers / metabolism Galactans / metabolism* Galactose / metabolism Galactosyltransferases / genetics* Galactosyltransferases / metabolism Gene Expression Regulation, Developmental Gene Expression Regulation, Plant* Glycosylation Hydroxyproline / metabolism Mucoproteins / genetics* Mucoproteins / metabolism Mutation Phenotype Pichia / genetics Pichia / metabolism Plant Leaves / genetics Plant Leaves / growth & development Plant Leaves / metabolism Plant Proteins / genetics Plant Proteins / metabolism Plant Roots / genetics Plant Roots / growth & development Plant Roots / metabolism Plants, Genetically Modified
IF 2.766
Times Cited 8
Arabidopsis / Cultured plant cells, genes pda08691