Host-dependent specialized metabolism of nitrogen export in actinorhizal nodules induced by diazotrophic Actinomycetota Frankia cluster-2
© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology.
| Veröffentlicht in: | Journal of experimental botany. - 1985. - 76(2025), 4 vom: 25. Feb., Seite 1164-1178 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2025
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| Zugriff auf das übergeordnete Werk: | Journal of experimental botany |
| Schlagworte: | Journal Article Frankia Actinorhizal symbiosis GS synthetase TCA cycle nitrogenase root nodules succinic semialdehyde dehydrogenase Nitrogen N762921K75 |
| Zusammenfassung: | © The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. Frankia cluster-2 strains are diazotrophs that engage in root nodule symbiosis with actinorhizal plants of the Cucurbitales and the Rosales. Previous studies have shown that an assimilated nitrogen source, presumably arginine, is exported to the host in nodules of Datisca glomerata (Cucurbitales), while a different metabolite is exported in the nodules of Ceanothus thyrsiflorus (Rosales). To investigate if an assimilated nitrogen form is commonly exported to the host by cluster-2 strains, and which metabolite would be exported in Ceanothus, we analysed gene expression levels, metabolite profiles, and enzyme activities in nodules. We conclude that the export of assimilated nitrogen in symbiosis seems to be a common feature for Frankia cluster-2 strains, but the source of nitrogen is host dependent. The export of assimilated ammonium to the host suggests that 2-oxoglutarate is drawn from the tricarboxylic acid (TCA) cycle at a high rate. This specialized metabolism obviates the need for the reductive branch of the TCA cycle. We found that several genes encoding enzymes of central carbon and nitrogen metabolism were lacking in Frankia cluster-2 genomes: the glyoxylate shunt and succinate semialdehyde dehydrogenase. This led to a linearization of the TCA cycle, and we hypothesized that this could explain the low saprotrophic potential of Frankia cluster-2 |
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| Beschreibung: | Date Completed 25.04.2025 Date Revised 25.04.2025 published: Print Citation Status MEDLINE |
| ISSN: | 1460-2431 |
| DOI: | 10.1093/jxb/erae446 |