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New Phytol. 2019 Apr 22. doi: 10.1111/nph.15867. [Epub ahead of print]

Arabinose biosynthesis is critical for salt stress tolerance in Arabidopsis.

Author information

1
CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China.
2
Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN, 47907, USA.
3
State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, 150040, China.
4
Maize Research Institute, Southwest University, Chongqing, 400715, China.
5
Jilin Provincial Key laboratory of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun, Jilin, 130033, China.
6
Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA.
7
Food Engineering Department, Ordu University, Ordu, 52200, Turkey.
8
Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
9
Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA.

Abstract

The capability to maintain cell wall integrity is critical for plants to adapt to unfavourable conditions. l-Arabinose (Ara) is a constituent of several cell wall polysaccharides and many cell wall-localised glycoproteins, but so far the contribution of Ara metabolism to abiotic stress tolerance is still poorly understood. Here, we report that mutations in the MUR4 (also known as HSR8) gene, which is required for the biosynthesis of UDP-Arap in Arabidopsis, led to reduced root elongation under high concentrations of NaCl, KCl, NaNO3 , or KNO3 . The short root phenotype of the mur4/hsr8 mutants under high salinity is rescued by exogenous Ara or gum arabic, a commercial product of arabinogalactan proteins (AGPs) from Acacia senegal. Mutation of the MUR4 gene led to abnormal cell-cell adhesion under salt stress. MUR4 forms either a homodimer or heterodimers with its isoforms. Analysis of the higher order mutants of MUR4 with its three paralogues, MURL, DUR, MEE25, reveals that the paralogues of MUR4 also contribute to the biosynthesis of UDP-Ara and are critical for root elongation. Taken together, our work revealed the importance of the Ara metabolism in salt stress tolerance and also provides new insights into the enzymes involved in the UDP-Ara biosynthesis in plants.

KEYWORDS:

Arabidopsis; arabinogalactan protein; arabinose; cell wall integrity; root elongation; salt stress

PMID:
31009077
DOI:
10.1111/nph.15867

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