Arabidopsis thaliana branching enzyme 1 is essential for amylopectin biosynthesis and cesium tolerance
Copyright © 2020 Elsevier GmbH. All rights reserved.
| Veröffentlicht in: | Journal of plant physiology. - 1979. - 252(2020) vom: 15. Sept., Seite 153208 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2020
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| Zugriff auf das übergeordnete Werk: | Journal of plant physiology |
| Schlagworte: | Journal Article Amylopectin Arabidopsis thaliana Branching enzyme Cesium tolerant Arabidopsis Proteins Cesium 1KSV9V4Y4I 9037-22-3 BE1 protein, Arabidopsis mehr... |
| Zusammenfassung: | Copyright © 2020 Elsevier GmbH. All rights reserved. Arabidopsis thaliana BRANCHING ENZYME 1 (AtBE1) is a chloroplast-localized embryo-lethal gene previously identified in knockout mutants. AtBE1 is thought to function in carbohydrate metabolism; however, this has not been experimentally demonstrated. Chlorosis is a typical symptom of cesium (Cs) toxicity in plants. The genetic target of Cs toxicity is largely unknown. Here, we isolated a Cs+-tolerant and chlorophyll-defective Arabidopsis ethyl methanesulfonate (EMS) mutant, atbe1-5. Mapping by sequencing and genetic complementation confirmed that a single amino acid change (P749S) in a random coil motif of AtBE1 confers the mutant's Cs+-tolerant and chlorophyll-defective phenotype. An isothermal titration calorimetry assay determined that the 749th residue is the Cs+-binding site and hence likely the target of Cs+ toxicity. We hypothesized that binding of Cs+ to the 749th residue of AtBE1 inhibits the enzyme's activity and confers Cs+ toxicity, which in turn reduces photosynthetic efficiency. In support with this hypothesis, atbe1-5 leaves have a reduced photosynthetic efficiency, and their amylose and amylopectin contents are ∼60 % and ∼1%, respectively, of those in Col-0 ecotype leaves. Leaves of the mutant have a lower sucrose, but higher maltose, concentration than those of Col-0. This study demonstrated that AtBE1 is an essential gene for amylopectin and amylose biosynthesis, as well as the target of Cs+ toxicity; therefore, it can serve as a genetic locus for engineering plants to extract Cs+ from contaminated soil while maintaining growth |
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| Beschreibung: | Date Completed 01.03.2021 Date Revised 01.03.2021 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1618-1328 |
| DOI: | 10.1016/j.jplph.2020.153208 |