Dataset Information

The cell wall pectic polymer rhamnogalacturonan-II is required for proper pollen tube elongation: implications of a putative sialyltransferase-like protein.

ABSTRACT:

Background and aims

Rhamnogalacturonan-II (RG-II) is one of the pectin motifs found in the cell wall of all land plants. It contains sugars such as 2-keto-3-deoxy-d-lyxo-heptulosaric acid (Dha) and 2-keto-3-deoxy-d-manno-octulosonic acid (Kdo), and within the wall RG-II is mostly found as a dimer via a borate diester cross-link. To date, little is known regarding the biosynthesis of this motif. Here, after a brief review of our current knowledge on RG-II structure, biosynthesis and function in plants, this study explores the implications of the presence of a Golgi-localized sialyltransferase-like 2 (SIA2) protein that is possibly involved in the transfer of Dha or Kdo in the RG-II of Arabidopsis thaliana pollen tubes, a fast-growing cell type used as a model for the study of cell elongation.

Methods

Two heterozygous mutant lines of arabidopsis (sia2-1+/- and qrt1 × sia2-2+/-) were investigated. sia2-2+/- was in a quartet1 background and the inserted T-DNA contained the reporter gene ?-glucuronidase (GUS) under the pollen-specific promoter LAT52. Pollen germination and pollen tube phenotype and growth were analysed both in vitro and in vivo by microscopy.

Key results

Self-pollination of heterozygous lines produced no homozygous plants in the progeny, which may suggest that the mutation could be lethal. Heterozygous mutants displayed a much lower germination rate overall and exhibited a substantial delay in germination (20 h of delay to reach 30 % of pollen grain germination compared with the wild type). In both lines, mutant pollen grains that were able to produce a tube had tubes that were either bursting, abnormal (swollen or dichotomous branching tip) or much shorter compared with wild-type pollen tubes. In vivo, mutant pollen tubes were restricted to the style, whereas the wild-type pollen tubes were detected at the base of the ovary.

Conclusions

This study highlights that the mutation in arabidopsis SIA2 encoding a sialyltransferase-like protein that may transfer Dha or Kdo on the RG-II motif has a dramatic effect on the stability of the pollen tube cell wall.

SUBMITTER: Dumont M

PROVIDER: S-EPMC4195553 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

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Publications

The cell wall pectic polymer rhamnogalacturonan-II is required for proper pollen tube elongation: implications of a putative sialyltransferase-like protein.

Dumont Marie M Lehner Arnaud A Bouton Sophie S Kiefer-Meyer Marie Christine MC Voxeur Aline A Pelloux Jérôme J Lerouge Patrice P Mollet Jean-Claude JC

Annals of botany 20140513 6

<h4>Background and aims</h4>Rhamnogalacturonan-II (RG-II) is one of the pectin motifs found in the cell wall of all land plants. It contains sugars such as 2-keto-3-deoxy-d-lyxo-heptulosaric acid (Dha) and 2-keto-3-deoxy-d-manno-octulosonic acid (Kdo), and within the wall RG-II is mostly found as a dimer via a borate diester cross-link. To date, little is known regarding the biosynthesis of this motif. Here, after a brief review of our current knowledge on RG-II structure, biosynthesis and funct ...[more]

PMID: 24825296

Similar Datasets

Project description:The primary cell walls of land plants are composed principally of a load bearing cellulose microfibril-hemicellulose network embedded in a matrix of pectic polysaccharides. The pectic matrix is multifunctional and in additional to a directly structural role it is central to many fundamental plant processes including cell expansion, defence and cell signalling. The sequencing of the Arabidopsis genome has revealed the massive investment made by plants in modulating the pectic matrix in response to local functional requirements but despite concerted biochemical-based efforts over many years none of the genes involved in pectin biosynthesis/pectic matrix assembly have so far been identified. The pectin matrix contains some of the most complex polysaccharides found in nature and based on linkage analysis it is known that at least 53 glycosyltransferases must be involved in its construction. Our proposal to identify genes involved in pectin biosynthesis and matrix assembly exploits the well characterised phenomenon that many plants and cultured plant cells that are exposed to treatments that disrupt the synthesis of one cell wall component are capable of a compensatory increases in other components - including pectin. Specifically suspension cultured cells that are incrementally exposed to increasing concentrations of the herbicide 26-dichlorobenzonitrile (DCB) which specifically inhibits cellulose synthesis compensate for the resulting almost complete loss of cellulose from their cell walls by constructing walls made predominantly of pectin. We believe that the significant up-regulation of pectin biosynthesis in this system offers an opportunity to identify genes that function in the assembly of the pectic matrix by microarray comparison of transcripts of DCB-treated Arabidopsis cells with untreated cells. The use of Arabidopsis suspension-cultured cells rather than plants or seedlings offers the significant advantage that extracted RNA would be derived from only one cell type. It is anticipated therefore that the output from a transcriptome analysis of this system will indicate a number of genes of unknown function and lead to the identification of genes involved in pectin biosynthesis and the assembly of the pectin matrix. Keywords: compound_treatment_design

Dataset Information

The cell wall pectic polymer rhamnogalacturonan-II is required for proper pollen tube elongation: implications of a putative sialyltransferase-like protein.

Background and aims

Methods

Key results

Conclusions

Publications

The cell wall pectic polymer rhamnogalacturonan-II is required for proper pollen tube elongation: implications of a putative sialyltransferase-like protein.

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