Galactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers.
The biosynthesis of plant cell wall polysaccharides requires the concerted action of nucleotide sugar interconversion enzymes, nucleotide sugar transporters, and glycosyl transferases. How cell wall synthesis in planta is regulated, however, remains unclear. The root epidermal bulger 1 (reb1) mutant...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
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2002
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| _version_ | 1797093035984551936 |
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| author | Seifert, G Barber, C Wells, B Dolan, L Roberts, K |
| author_facet | Seifert, G Barber, C Wells, B Dolan, L Roberts, K |
| author_sort | Seifert, G |
| collection | OXFORD |
| description | The biosynthesis of plant cell wall polysaccharides requires the concerted action of nucleotide sugar interconversion enzymes, nucleotide sugar transporters, and glycosyl transferases. How cell wall synthesis in planta is regulated, however, remains unclear. The root epidermal bulger 1 (reb1) mutant in Arabidopsis thaliana is partially deficient in cell wall arabinogalactan-protein (AGP), indicating a role for REB1 in AGP biosynthesis. We show that REB1 is allelic to ROOT HAIR DEFICIENT 1 (RHD1), one of five ubiquitously expressed genes that encode isoforms of UDP-D-glucose 4-epimerase (UGE), an enzyme that acts in the formation of UDP-D-galactose (UDP-D-Gal). The RHD1 isoform is specifically required for the galactosylation of xyloglucan (XG) and type II arabinogalactan (AGII) but is not involved either in D-galactose detoxification or in galactolipid biosynthesis. Epidermal cell walls in the root expansion zone lack arabinosylated (1-->6)-beta-D-galactan and galactosylated XG. In cortical cells of rhd1, galactosylated XG is absent, but an arabinosylated (1-->6)-beta-D-galactan is present. We conclude that the flux of galactose from UDP-D-Gal into different downstream products is compartmentalized at the level of cytosolic UGE isoforms. This suggests that substrate channeling plays a role in the regulation of plant cell wall biosynthesis. |
| first_indexed | 2024-03-07T03:54:35Z |
| format | Journal article |
| id | oxford-uuid:c26c9a73-3a8d-4db6-85ca-ff4324263e0f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:54:35Z |
| publishDate | 2002 |
| record_format | dspace |
| spelling | oxford-uuid:c26c9a73-3a8d-4db6-85ca-ff4324263e0f2022-03-27T06:08:52ZGalactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:c26c9a73-3a8d-4db6-85ca-ff4324263e0fEnglishSymplectic Elements at Oxford2002Seifert, GBarber, CWells, BDolan, LRoberts, KThe biosynthesis of plant cell wall polysaccharides requires the concerted action of nucleotide sugar interconversion enzymes, nucleotide sugar transporters, and glycosyl transferases. How cell wall synthesis in planta is regulated, however, remains unclear. The root epidermal bulger 1 (reb1) mutant in Arabidopsis thaliana is partially deficient in cell wall arabinogalactan-protein (AGP), indicating a role for REB1 in AGP biosynthesis. We show that REB1 is allelic to ROOT HAIR DEFICIENT 1 (RHD1), one of five ubiquitously expressed genes that encode isoforms of UDP-D-glucose 4-epimerase (UGE), an enzyme that acts in the formation of UDP-D-galactose (UDP-D-Gal). The RHD1 isoform is specifically required for the galactosylation of xyloglucan (XG) and type II arabinogalactan (AGII) but is not involved either in D-galactose detoxification or in galactolipid biosynthesis. Epidermal cell walls in the root expansion zone lack arabinosylated (1-->6)-beta-D-galactan and galactosylated XG. In cortical cells of rhd1, galactosylated XG is absent, but an arabinosylated (1-->6)-beta-D-galactan is present. We conclude that the flux of galactose from UDP-D-Gal into different downstream products is compartmentalized at the level of cytosolic UGE isoforms. This suggests that substrate channeling plays a role in the regulation of plant cell wall biosynthesis. |
| spellingShingle | Seifert, G Barber, C Wells, B Dolan, L Roberts, K Galactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers. |
| title | Galactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers. |
| title_full | Galactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers. |
| title_fullStr | Galactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers. |
| title_full_unstemmed | Galactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers. |
| title_short | Galactose biosynthesis in Arabidopsis: genetic evidence for substrate channeling from UDP-D-galactose into cell wall polymers. |
| title_sort | galactose biosynthesis in arabidopsis genetic evidence for substrate channeling from udp d galactose into cell wall polymers |
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