Pectin Biosynthesis: GALS1 in <i>Arabidopsis thaliana</i> Is a β-1,4-Galactan β-1,4-Galactosyltransferase

Liwanag, April Jennifer Madrid; Ebert, Berit; Verhertbruggen, Yves; Rennie, Emilie A.; Rautengarten, Carsten; Oikawa, Ai; Andersen, Mathias Christian Franch; Clausen, Mads Hartvig; Scheller, Henrik Vibe

doi:10.1105/tpc.112.106625

Cited by 118 publications

(114 citation statements)

References 61 publications

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“…Recently, it was demonstrated that the Gal content of the cell wall could be easily manipulated (35); this is probably due to the extension of galactan side chains on the RG-I backbone. In contrast, no changes in the levels of Rha were observed in either the urgt1 mutants or overexpression plants.…”

Section: Discussionmentioning

confidence: 99%

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The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis

Rautengarten

Ebert

Moreno

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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102

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Plant cells are surrounded by a cell wall that plays a key role in plant growth, structural integrity, and defense. The cell wall is a complex and diverse structure that is mainly composed of polysaccharides. The majority of noncellulosic cell wall polysaccharides are produced in the Golgi apparatus from nucleotide sugars that are predominantly synthesized in the cytosol. The transport of these nucleotide sugars from the cytosol into the Golgi lumen is a critical process for cell wall biosynthesis and is mediated by a family of nucleotide sugar transporters (NSTs). Numerous studies have sought to characterize substrate-specific transport by NSTs; however, the availability of certain substrates and a lack of robust methods have proven problematic. Consequently, we have developed a novel approach that combines reconstitution of NSTs into liposomes and the subsequent assessment of nucleotide sugar uptake by mass spectrometry. To address the limitation of substrate availability, we also developed a two-step reaction for the enzymatic synthesis of UDP-L-rhamnose (Rha) by expressing the two active domains of the Arabidopsis UDP-L-Rha synthase. The liposome approach and the newly synthesized substrates were used to analyze a clade of Arabidopsis NSTs, resulting in the identification and characterization of six bifunctional UDP-LRha/UDP-D-galactose (Gal) transporters (URGTs). Further analysis of loss-of-function and overexpression plants for two of these URGTs supported their roles in the transport of UDP-L-Rha and UDP-D-Gal for matrix polysaccharide biosynthesis. membrane transport | proteoliposomes | glycan biosynthesis | galactan

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Section: Discussionmentioning

confidence: 99%

“…Alcohol-insoluble residue from leaves of 6-wk-old plants was prepared as described earlier (45) (SI Materials and Methods). Cell wall preparations from URGT1-overexpressing plants were analyzed by digestion with an endo-β-1,4-galactanase from Aspergillus niger (Megazyme International) as described previously (35).…”

mentioning

confidence: 99%

The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis

Rautengarten

Ebert

Moreno

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

102

164

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“…Three days after infiltration, five entire leaves were harvested and microsomes were extracted . Galactosyltransferase activity was determined essentially as described previously (Liwanag et al, 2012) using 40 mg of microsomal protein, 10 nCi of UDP-[…”

Section: Nicotiana Benthamiana Microsome Preparation and Galactosyltrmentioning

confidence: 99%

MUCILAGE-RELATED10 Produces Galactoglucomannan That Maintains Pectin and Cellulose Architecture in Arabidopsis Seed Mucilage

et al. 2015

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Plants invest a lot of their resources into the production of an extracellular matrix built of polysaccharides. While the composition of the cell wall is relatively well characterized, the functions of the individual polymers and the enzymes that catalyze their biosynthesis remain poorly understood. We exploited the Arabidopsis (Arabidopsis thaliana) seed coat epidermis (SCE) to study cell wall synthesis. SCE cells produce mucilage, a specialized secondary wall that is rich in pectin, at a precise stage of development. A coexpression search for MUCILAGE-RELATED (MUCI) genes identified MUCI10 as a key determinant of mucilage properties. MUCI10 is closely related to a fenugreek (Trigonella foenumgraecum) enzyme that has in vitro galactomannan a-1,6-galactosyltransferase activity. Our detailed analysis of the muci10 mutants demonstrates that mucilage contains highly branched galactoglucomannan (GGM) rather than unbranched glucomannan. MUCI10 likely decorates glucomannan, synthesized by CELLULOSE SYNTHASE-LIKE A2, with galactose residues in vivo. The degree of galactosylation is essential for the synthesis of the GGM backbone, the structure of cellulose, mucilage density, as well as the adherence of pectin. We propose that GGM scaffolds control mucilage architecture along with cellulosic rays and show that Arabidopsis SCE cells represent an excellent model in which to study the synthesis and function of GGM. Arabidopsis natural varieties with defects similar to muci10 mutants may reveal additional genes involved in GGM synthesis. Since GGM is the most abundant hemicellulose in the secondary walls of gymnosperms, understanding its biosynthesis may facilitate improvements in the production of valuable commodities from softwoods.

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“…We identified the Populus genes encoding glycosyl transferases involved in the biosynthesis of homogalacturonan (Atmodjo et al, 2011), RG-I (Harholt et al, 2006;Liwanag et al, 2012), RG-II (Egelund et al, 2006), and xyloglucan (Cavalier and Keegstra, 2006;Zabotina et al, 2008;Chou et al, 2012) (Supplemental Data Set 9). As expected, the majority of these genes were highly expressed in primary walled cambial and radially expanding tissues (sample cluster ii; Figure 5A).…”

Section: Primary Cell Wall Polysaccharide Biosynthetic Genes Continuementioning

confidence: 99%

AspWood: High-Spatial-Resolution Transcriptome Profiles Reveal Uncharacterized Modularity of Wood Formation in Populus tremula

et al. 2017

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Trees represent the largest terrestrial carbon sink and a renewable source of ligno-cellulose. There is significant scope for yield and quality improvement in these largely undomesticated species, and efforts to engineer elite varieties will benefit from improved understanding of the transcriptional network underlying cambial growth and wood formation. We generated highspatial-resolution RNA sequencing data spanning the secondary phloem, vascular cambium, and wood-forming tissues of Populus tremula. The transcriptome comprised 28,294 expressed, annotated genes, 78 novel protein-coding genes, and 567 putative long intergenic noncoding RNAs. Most paralogs originating from the Salicaceae whole-genome duplication had diverged expression, with the exception of those highly expressed during secondary cell wall deposition. Coexpression network analyses revealed that regulation of the transcriptome underlying cambial growth and wood formation comprises numerous modules forming a continuum of active processes across the tissues. A comparative analysis revealed that a majority of these modules are conserved in Picea abies. The high spatial resolution of our data enabled identification of novel roles for characterized genes involved in xylan and cellulose biosynthesis, regulators of xylem vessel and fiber differentiation and lignification. An associated web resource (AspWood, http://aspwood.popgenie.org) provides interactive tools for exploring the expression profiles and coexpression network.

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Pectin Biosynthesis: GALS1 in Arabidopsis thaliana Is a β-1,4-Galactan β-1,4-Galactosyltransferase

Cited by 118 publications

References 61 publications

The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis

The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis

MUCILAGE-RELATED10 Produces Galactoglucomannan That Maintains Pectin and Cellulose Architecture in Arabidopsis Seed Mucilage

AspWood: High-Spatial-Resolution Transcriptome Profiles Reveal Uncharacterized Modularity of Wood Formation in Populus tremula

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