Functional characterisation and in silico modelling of MdPSY2 variants and MdPSY5 phytoene synthases from Malus domestica
Copyright © 2020 Elsevier GmbH. All rights reserved.
| Veröffentlicht in: | Journal of plant physiology. - 1979. - 249(2020) vom: 25. Juni, Seite 153166 |
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| 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 Carotenoids Heterologous complementation In silico modelling Malus domestica cv. ‘Fuji’ Phytoene synthase Plant Proteins Alkyl and Aryl Transferases EC 2.5.- |
| Zusammenfassung: | Copyright © 2020 Elsevier GmbH. All rights reserved. Carotenoids are plastid isoprenoid pigments that play critical roles in light harvesting, photoprotection, and phytohormone biosynthesis. They are also vitamin-A precursors and antioxidant molecules important for human nutrition. Apples (e.g. Malus x domestica Borkh), one of the most widely consumed fruits with high nutrient levels, have a very low carotenoid concentration in flesh, compared with other fruits and vegetables. This could be explained by a deficiency in carotenoid synthesis/accumulation and/or accelerated degradation. We analysed the contribution of M. domestica cv. 'Fuji' phytoene synthase (PSY) in the biosynthesis of carotenoids and determined that among four MdPSY genes present in the organism, MdPSY2 and MdPSY5 are highly expressed in leaves and during fruit ripening in line with an increment in carotenoid content in fruits. Furthermore, two representative polymorphic MdPSY2 variants were found, one with a Tyr358Phe substitution (MdPSY2_F) and the other that additionally has a six-amino-acid deletion in the signal peptide (MdPSY2_CG). MdPSY2, MdPSY5, MdPSY2_F and MdPSY2_CG are all localised in plastids. Interestingly, the polymorphic MdPSY2_F and MdPSY2_CG variants show lower enzymatic activity than the wild-type form in a heterologous complementation assay, which could be attributed to the Tyr358Phe substitution close to the active-site pocket, as was suggested by 3-D modelling analysis. The presence of polymorphic MdPSY2 variants with lower enzymatic activity could be partially responsible for the low carotenoid content in Fuji apple fruits |
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| Beschreibung: | Date Completed 13.10.2020 Date Revised 13.10.2020 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1618-1328 |
| DOI: | 10.1016/j.jplph.2020.153166 |