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Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1
The plastidial α-glucan phosphorylase (PHS1) can elongate and degrade maltooligosaccharides (MOSs), but its exact physiological role in plants is poorly understood. Here, we discover a specialized role of PHS1 in establishing the unique bimodal characteristic of starch granules in wheat (Triticum sp...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10615211/ https://www.ncbi.nlm.nih.gov/pubmed/37595145 http://dx.doi.org/10.1093/plcell/koad217 |
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author | Kamble, Nitin Uttam Makhamadjonov, Farrukh Fahy, Brendan Martins, Carlo Saalbach, Gerhard Seung, David |
author_facet | Kamble, Nitin Uttam Makhamadjonov, Farrukh Fahy, Brendan Martins, Carlo Saalbach, Gerhard Seung, David |
author_sort | Kamble, Nitin Uttam |
collection | PubMed |
description | The plastidial α-glucan phosphorylase (PHS1) can elongate and degrade maltooligosaccharides (MOSs), but its exact physiological role in plants is poorly understood. Here, we discover a specialized role of PHS1 in establishing the unique bimodal characteristic of starch granules in wheat (Triticum spp.) endosperm. Wheat endosperm contains large A-type granules that initiate at early grain development and small B-type granules that initiate in later grain development. We demonstrate that PHS1 interacts with B-GRANULE CONTENT1 (BGC1), a carbohydrate-binding protein essential for normal B-type granule initiation. Mutants of tetraploid durum wheat (Triticum turgidum) deficient in all homoeologs of PHS1 had normal A-type granules but fewer and larger B-type granules. Grain size and starch content were not affected by the mutations. Further, by assessing granule numbers during grain development in the phs1 mutant and using a double mutant defective in both PHS1 and BGC1, we demonstrate that PHS1 is exclusively involved in B-type granule initiation. The total starch content and number of starch granules per chloroplast in leaves were not affected by loss of PHS1, suggesting that its role in granule initiation in wheat is limited to the endosperm. We therefore propose that the initiation of A- and B-type granules occurs via distinct biochemical mechanisms, where PHS1 plays an exclusive role in B-type granule initiation. |
format | Online Article Text |
id | pubmed-10615211 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-106152112023-10-31 Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1 Kamble, Nitin Uttam Makhamadjonov, Farrukh Fahy, Brendan Martins, Carlo Saalbach, Gerhard Seung, David Plant Cell Research Article The plastidial α-glucan phosphorylase (PHS1) can elongate and degrade maltooligosaccharides (MOSs), but its exact physiological role in plants is poorly understood. Here, we discover a specialized role of PHS1 in establishing the unique bimodal characteristic of starch granules in wheat (Triticum spp.) endosperm. Wheat endosperm contains large A-type granules that initiate at early grain development and small B-type granules that initiate in later grain development. We demonstrate that PHS1 interacts with B-GRANULE CONTENT1 (BGC1), a carbohydrate-binding protein essential for normal B-type granule initiation. Mutants of tetraploid durum wheat (Triticum turgidum) deficient in all homoeologs of PHS1 had normal A-type granules but fewer and larger B-type granules. Grain size and starch content were not affected by the mutations. Further, by assessing granule numbers during grain development in the phs1 mutant and using a double mutant defective in both PHS1 and BGC1, we demonstrate that PHS1 is exclusively involved in B-type granule initiation. The total starch content and number of starch granules per chloroplast in leaves were not affected by loss of PHS1, suggesting that its role in granule initiation in wheat is limited to the endosperm. We therefore propose that the initiation of A- and B-type granules occurs via distinct biochemical mechanisms, where PHS1 plays an exclusive role in B-type granule initiation. Oxford University Press 2023-08-18 /pmc/articles/PMC10615211/ /pubmed/37595145 http://dx.doi.org/10.1093/plcell/koad217 Text en © The Author(s) 2023. Published by Oxford University Press on behalf of American Society of Plant Biologists. https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Article Kamble, Nitin Uttam Makhamadjonov, Farrukh Fahy, Brendan Martins, Carlo Saalbach, Gerhard Seung, David Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1 |
title | Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1 |
title_full | Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1 |
title_fullStr | Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1 |
title_full_unstemmed | Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1 |
title_short | Initiation of B-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase PHS1 |
title_sort | initiation of b-type starch granules in wheat endosperm requires the plastidial α-glucan phosphorylase phs1 |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10615211/ https://www.ncbi.nlm.nih.gov/pubmed/37595145 http://dx.doi.org/10.1093/plcell/koad217 |
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