Cu+‐chaperones are a diverse group of proteins that allocate Cu+ions to specific copper proteins, creating different copper pools targeted to specific physiological processes. Symbiotic nitrogen fixation carried out in legume root nodules indirectly requires relatively large amounts of copper, for example for energy delivery via respiration, for which targeted copper deliver systems would be required. MtNCC1 is a nodule‐specific Cu+‐chaperone encoded in the A subset of the copper proteome is also affected in the
Iron is an essential cofactor for symbiotic nitrogen fixation, required by many of the enzymes involved, including signal transduction proteins, O2homeostasis systems, and nitrogenase itself. Consequently, host plants have developed a transport network to deliver essential iron to nitrogen‐fixing nodule cells. Ferroportin family members in model legume These data indicate that MtFPN2 plays a primary role in iron delivery to nitrogen‐fixing bacteroids in
- NSF-PAR ID:
- 10452856
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 228
- Issue:
- 1
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 194-209
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary Medicago truncatula genome, with a N‐terminus Atx1‐like domain that can bind Cu+with picomolar affinities. MtNCC1 is able to interact with nodule‐specific Cu+‐importer MtCOPT1.MtNCC1 is expressed primarily from the late infection zone to the early fixation zone and is located in the cytosol, associated with plasma and symbiosome membranes, and within nuclei. Consistent with its key role in nitrogen fixation,ncc1 mutants have a severe reduction in nitrogenase activity and a 50% reduction in copper‐dependent cytochromec oxidase activity.ncc1 mutant nodules. Many of these proteins can be pulled down when using a Cu+‐loaded N‐terminal MtNCC1 moiety as a bait, indicating a role in nodule copper homeostasis and in copper‐dependent physiological processes. Overall, these data suggest a pleiotropic role of MtNCC1 in copper delivery for symbiotic nitrogen fixation. -
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Abstract Transport systems are crucial in many plant processes, including plant–microbe interactions. Nodule formation and function in legumes involve the expression and regulation of multiple transport proteins, and many are still uncharacterized, particularly for nitrogen transport. Amino acids originating from the nitrogen-fixing process are an essential form of nitrogen for legumes. This work evaluates the role of MtN21 (henceforth MtUMAMIT14), a putative transport system from the MtN21/EamA-like/UMAMIT family, in nodule formation and nitrogen fixation in
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null (Ed.)In legumes, symbiotic nitrogen (N) fixation (SNF) occurs in specialized organs called nodules after successful interactions between legume hosts and rhizobia. In a nodule, N-fixing rhizobia are surrounded by symbiosome membranes, through which the exchange of nutrients and ammonium occurs between bacteria and the host legume. Phosphorus (P) is an essential macronutrient, and N2-fixing legumes have a higher requirement for P than legumes grown on mineral N. As in the previous studies, in P deficiency, barrel medic (Medicago truncatula) plants had impaired SNF activity, reduced growth, and accumulated less phosphate in leaves, roots, and nodules compared with the plants grown in P sufficient conditions. Membrane lipids in M. truncatula tissues were assessed using electrospray ionization–mass spectrometry. Galactolipids were found to increase in P deficiency, with declines in phospholipids (PL), especially in leaves. Lower PL losses were found in roots and nodules. Subsequently, matrix-assisted laser desorption/ionization–mass spectrometry imaging was used to spatially map the distribution of the positively charged phosphatidylcholine (PC) species in nodules in both P-replete and P-deficient conditions. Our results reveal heterogeneous distribution of several PC species in nodules, with homogeneous distribution of other PC classes. In P poor conditions, some PC species distributions were observed to change. The results suggest that specific PC species may be differentially important in diverse nodule zones and cell types, and that membrane lipid remodeling during P stress is not uniform across the nodule.more » « less
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