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
Yellow Stripe‐Like (YSL) proteins are a family of plant transporters that are typically involved in transition metal homeostasis. Three of the four YSL clades (I, II and IV) transport metals complexed with the non‐proteinogenic amino acid nicotianamine or its derivatives. No such capability has been shown for any member of clade III, but the link between these YSLs and metal homeostasis could be masked by functional redundancy. We studied the role of the clade III YSL protein MtSYL7 in
- PAR ID:
- 10452100
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Plant, Cell & Environment
- Volume:
- 44
- Issue:
- 6
- ISSN:
- 0140-7791
- Page Range / eLocation ID:
- p. 1908-1920
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary Medicago truncatula were identified and their expression was determined. Yeast complementation assays, immunolocalization, characterization of atnt1 insertional mutant line, and synchrotron‐based X‐ray fluorescence assays were carried out in the nodule‐specificM. truncatula ferroportinMedicago truncatula nodule‐specific geneFerroportin2 (MtFPN2 ) is an iron‐efflux protein. MtFPN2 is located in intracellular membranes in the nodule vasculature and in inner nodule tissues, as well as in the symbiosome membranes in the interzone and early‐fixation zone of the nodules. Loss‐of‐function ofMtFPN2 alters iron distribution and speciation in nodules, reducing nitrogenase activity and biomass production. Using promoters with different tissular activity to driveMtFPN2 expression inMtFPN2 mutants, we determined that expression in the inner nodule tissues is sufficient to restore the phenotype, while confiningMtFPN2 expression to the vasculature did not improve the mutant phenotype.M. truncatula nodules. -
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Medicago truncatula . To dissect this transporter’s role, we assessed the expression ofMtUMAMIT14 using GUS staining, localized the corresponding protein inM. truncatula root and tobacco leaf cells, and investigated two independentMtUMAMIT14 mutant lines. Our results indicate that MtUMAMIT14 is localized in endosomal structures and is expressed in both the infection zone and interzone of nodules. Comparison of mutant and wild-typeM. truncatula indicates MtUMAMIT14, the expression of which is dependent on the presence ofNIN, DNF1, andDNF2 , plays a role in nodule formation and nitrogen-fixation. While the function of the transporter is still unclear, our results connect root nodule nitrogen fixation in legumes with the UMAMIT family. -
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The model legume
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