Effects of Pectin Molecular Weight Changes on the Structure, Dynamics, and Polysaccharide Interactions of Primary Cell Walls of Arabidopsis thaliana: Insights from Solid-State NMR

Pyae Phyo, Tuo Wang, Chaowen Xiao, Charles T. Anderson, Mei Hong

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Significant cellulose-pectin interactions in plant cell walls have been reported recently based on 2D 13C solid-state NMR spectra of intact cell walls, but how these interactions affect cell growth has not been probed. Here, we characterize two Arabidopsis thaliana lines with altered expression of the POLYGALACTURONASE INVOLVED IN EXPANSION1 (PGX1) gene, which encodes a polygalacturonase that cleaves homogalacturonan (HG). PGX1AT plants overexpress PGX1, have HG with lower molecular weight, and grow larger, whereas pgx1-2 knockout plants have HG with higher molecular weight and grow smaller. Quantitative 13C solid-state NMR spectra show that PGX1AT cell walls have lower galacturonic acid and xylose contents and higher HG methyl esterification than controls, whereas high molecular weight pgx1-2 walls have similar galacturonic acid content and methyl esterification as controls. 1H-transferred 13C INEPT spectra indicate that the interfibrillar HG backbones are more aggregated whereas the RG-I side chains are more dispersed in PGX1AT cell walls than in pgx1-2 walls. In contrast, the pectins that are close to cellulose become more mobile and have weaker cross peaks with cellulose in PGX1AT walls than in pgx1-2 walls. Together, these results show that polygalacturonase-mediated plant growth is accompanied by increased esterification and decreased cross-linking of HG, increased aggregation of interfibrillar HG, and weaker HG-cellulose interactions. These structural and dynamical differences give molecular insights into how pectins influence wall dynamics during cell growth.

Original languageEnglish (US)
Pages (from-to)2937-2950
Number of pages14
JournalBiomacromolecules
Volume18
Issue number9
DOIs
StatePublished - Sep 11 2017

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Polysaccharides
Cellulose
Esterification
Molecular weight
Cells
Nuclear magnetic resonance
Cell growth
Polygalacturonase
Pectins
Xylose
Acids
Agglomeration
Genes
pectin
polygalacturonic acid

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Biomaterials
  • Polymers and Plastics
  • Materials Chemistry

Cite this

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title = "Effects of Pectin Molecular Weight Changes on the Structure, Dynamics, and Polysaccharide Interactions of Primary Cell Walls of Arabidopsis thaliana: Insights from Solid-State NMR",
abstract = "Significant cellulose-pectin interactions in plant cell walls have been reported recently based on 2D 13C solid-state NMR spectra of intact cell walls, but how these interactions affect cell growth has not been probed. Here, we characterize two Arabidopsis thaliana lines with altered expression of the POLYGALACTURONASE INVOLVED IN EXPANSION1 (PGX1) gene, which encodes a polygalacturonase that cleaves homogalacturonan (HG). PGX1AT plants overexpress PGX1, have HG with lower molecular weight, and grow larger, whereas pgx1-2 knockout plants have HG with higher molecular weight and grow smaller. Quantitative 13C solid-state NMR spectra show that PGX1AT cell walls have lower galacturonic acid and xylose contents and higher HG methyl esterification than controls, whereas high molecular weight pgx1-2 walls have similar galacturonic acid content and methyl esterification as controls. 1H-transferred 13C INEPT spectra indicate that the interfibrillar HG backbones are more aggregated whereas the RG-I side chains are more dispersed in PGX1AT cell walls than in pgx1-2 walls. In contrast, the pectins that are close to cellulose become more mobile and have weaker cross peaks with cellulose in PGX1AT walls than in pgx1-2 walls. Together, these results show that polygalacturonase-mediated plant growth is accompanied by increased esterification and decreased cross-linking of HG, increased aggregation of interfibrillar HG, and weaker HG-cellulose interactions. These structural and dynamical differences give molecular insights into how pectins influence wall dynamics during cell growth.",
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Effects of Pectin Molecular Weight Changes on the Structure, Dynamics, and Polysaccharide Interactions of Primary Cell Walls of Arabidopsis thaliana : Insights from Solid-State NMR. / Phyo, Pyae; Wang, Tuo; Xiao, Chaowen; Anderson, Charles T.; Hong, Mei.

In: Biomacromolecules, Vol. 18, No. 9, 11.09.2017, p. 2937-2950.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of Pectin Molecular Weight Changes on the Structure, Dynamics, and Polysaccharide Interactions of Primary Cell Walls of Arabidopsis thaliana

T2 - Insights from Solid-State NMR

AU - Phyo, Pyae

AU - Wang, Tuo

AU - Xiao, Chaowen

AU - Anderson, Charles T.

AU - Hong, Mei

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