OsVTC1-1 RNAi Mutant with Reduction of Ascorbic Acid Synthesis Alters Cell Wall Sugar Composition and Cell Wall-Associated Proteins

Abstract

Ascorbic acid (AsA) or Vitamin C is an antioxidant molecule and plays an important role in many biological processes in plants. GDP-D-mannose pyrophosphorylase (GMP or VTC1) catalyzes the synthesis of GDP-D-mannose, which is a precursor for AsA production and is used for cell wall polysaccharide and glycoprotein synthesis. In rice, the OsVTC1 gene consists of three homologs, including OsVTC1-1, OsVTC1-3 and OsVTC1-8. In this study, we characterized wild type (WT) and OsVTC1-1 RNAi lines (RI1-2 and RI1-3) and showed that the transcript levels of most genes in the AsA synthesis pathway, AsA content and leaf anatomical parameters in RNAi lines were reduced, revealing that OsVTC1-1 is involved in AsA synthesis. To further study the role of OsVTC1-1 gene, cell wall monosaccharide composition, transcriptome and proteome were compared, with specific attention paid to their wild type and OsVTC1-1 RNAi lines. Mannose and galactose composition (mole%) were decreased in OsVTC1-1 RNAi lines. Additionally, reduction of cell wall-associated proteins, such as kinesin, expansin, beta-galactosidase and cellulose synthase were observed in OsVTC1-1 RNAi lines. Our results suggest that OsVTC1-1 gene plays an important role in AsA synthesis and in cell wall-related processes.

Transcriptome Analysis Reveals That Ascorbic Acid Treatment Enhances the Cold Tolerance of Tea Plants through Cell Wall Remodeling

“…As a result of the large number of DEGs associated with cell wall remodeling in the CV vs. CO comparison, we speculate that cells activate a cell wall compensatory pathway to strengthen the cell wall in order to mitigate the negative effects of cold stress, and AsA may protect cell wall integrity under cold stress. Our hypothesis is supported by the finding that OsVTC1-1 RNAi lines contain lower levels of AsA and cell-wall-related proteins, such as cellulose synthase, β-galactosidase, and expansin [53].…”

Decrypting Molecular Mechanisms Involved in Counteracting Copper and Nickel Toxicity in Jack Pine (Pinus banksiana) Based on Transcriptomic Analysis

“…N-glycosylation can alter various properties such as polarity, solubility, reactivity, and cell compartment localization, which can alter protein conformation and overall function [183][184][185][186]. GDP mannose is also a precursor for GDP-fucose, which is a component of the cell wall that is involved in adhesion, polysaccharide crosslinking, and lignification [187][188][189][190]. Additionally, GDP mannose is a precursor for ascorbic acid, which is a multifunctional compound involved in stress signaling, defense processes, and crosstalk with phytohormones [188,191,192].…”

“…GDP mannose is also a precursor for GDP-fucose, which is a component of the cell wall that is involved in adhesion, polysaccharide crosslinking, and lignification [187][188][189][190]. Additionally, GDP mannose is a precursor for ascorbic acid, which is a multifunctional compound involved in stress signaling, defense processes, and crosstalk with phytohormones [188,191,192]. In Arabidopsis thaliana, knockout of the MPG gene leads to callose deposition in the primary cell wall, incomplete construction of the cell wall, and a considerable decrease in cellulose content [182].…”

Multiple Physiological and Biochemical Functions of Ascorbic Acid in Plant Growth, Development, and Abiotic Stress Response

“…Furthermore, changes in AsA content could also affect the composition of cell wall polysaccharides. For example, a comparison between wild-type rice and the OsVTC1-1 RNAi line shows reduced levels of galactose, mannose, and glucuronic acid in the OsVTC1-1 RNAi line compared to those in the wild-type seedling [113,114].…”