Trace metal nutrition and response to deficiency

Blaby-Haas, Crysten E.; Merchant, Sabeeha

doi:10.1016/b978-0-12-821430-5.00002-x

Cited by 4 publications

(3 citation statements)

References 190 publications

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“…The gene is generally tightly repressed in Fe-replete medium, making it a particularly sensitive marker of Fe status (Allen et al 2007b). Although there are other candidate reductases encoded in the Chlamydomonas genome that also respond to poor Fe nutrition (Blaby-Haas and Merchant 2023), the timing and magnitude of FRE1 expression compared to these other reductases suggests it as a key player responsible for Fe assimilation.…”

Section: Discussionmentioning

confidence: 99%

“…Chlamydomonas, which is in the green lineage, is a reference organism widely used for the study of chloroplast metabolism and photosynthesis (Salomé and Merchant 2019). We have developed this alga as a useful system for investigating trace metal homeostasis (Blaby-Haas & Merchant, 2012, 2023; Glaesener et al, 2013; Merchant et al, 2006). It is easy to manipulate the Fe content within the defined growth medium and homogenously supply Fe to cells without variations in organ, tissue, or cell type (Hui et al 2023).…”

Section: Introductionmentioning

confidence: 99%

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Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium

Liu,

Urzica,

Gallaher

et al. 2024

Preprint

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Low iron (Fe) bioavailability can limit the biosynthesis of Fe-containing proteins, which are especially abundant in photosynthetic organisms, thus negatively affecting global primary productivity. Understanding cellular coping mechanisms under Fe limitation is therefore of great interest. We surveyed the temporal responses of Chlamydomonas (Chlamydomonas reinhardtii) cells transitioning from an Fe-rich to an Fe-free medium to document their short- and long-term adjustments. While slower growth, chlorosis and lower photosynthetic parameters are evident only after one or more days in Fe-free medium, the abundance of some transcripts, such as those for genes encoding transporters and enzymes involved in Fe assimilation, change within minutes, before changes in intracellular Fe content are noticeable, suggestive of a sensitive mechanism for sensing Fe. Promoter reporter constructs indicate a transcriptional component to this immediate primary response. With acetate provided as a source of reduced carbon, transcripts encoding respiratory components are maintained relative to transcripts encoding components of photosynthesis and tetrapyrrole biosynthesis, indicating metabolic prioritization of respiration over photosynthesis. In contrast to the loss of chlorophyll, carotenoid content is maintained under Fe limitation despite a decrease in the transcripts for carotenoid biosynthesis genes, indicating carotenoid stability. These changes occur more slowly, only after the intracellular Fe quota responds, indicating a phased response in Chlamydomonas, involving both primary and secondary responses during acclimation to poor Fe nutrition.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium

Liu,

Urzica,

Gallaher

et al. 2024

Preprint

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“…ZNG1 is a eukaryote-specific subfamily of the nucleotide-dependent metallochaperones (NMCs) ( Blaby-Haas and Merchant, 2023 ). These proteins are also sometimes referred to as cobalamin biosynthesis proteins because of similarity to the CobW protein from bacteria ( Crouzet et al., 1991 ) or referred to as COG0523 ( Haas et al., 2009 ), a phylogeny-based designation from the database of Clusters of Orthologous Groups of proteins (COGs) ( Tatusov et al., 1997 ).…”

Section: Introductionmentioning

confidence: 99%

Two related families of metal transferases, ZNG1 and ZNG2, are involved in acclimation to poor Zn nutrition in Arabidopsis

Zhang,

Braynen,

Fahey

et al. 2023

Front. Plant Sci.

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Metal homeostasis has evolved to tightly modulate the availability of metals within the cell, avoiding cytotoxic interactions due to excess and protein inactivity due to deficiency. Even in the presence of homeostatic processes, however, low bioavailability of these essential metal nutrients in soils can negatively impact crop health and yield. While research has largely focused on how plants assimilate metals, acclimation to metal-limited environments requires a suite of strategies that are not necessarily involved in metal transport across membranes. The identification of these mechanisms provides a new opportunity to improve metal-use efficiency and develop plant foodstuffs with increased concentrations of bioavailable metal nutrients. Here, we investigate the function of two distinct subfamilies of the nucleotide-dependent metallochaperones (NMCs), named ZNG1 and ZNG2, that are found in plants, using Arabidopsis thaliana as a reference organism. AtZNG1 (AT1G26520) is an ortholog of human and fungal ZNG1, and like its previously characterized eukaryotic relatives, localizes to the cytosol and physically interacts with methionine aminopeptidase type I (AtMAP1A). Analysis of AtZNG1, AtMAP1A, AtMAP2A, and AtMAP2B transgenic mutants are consistent with the role of Arabidopsis ZNG1 as a Zn transferase for AtMAP1A, as previously described in yeast and zebrafish. Structural modeling reveals a flexible cysteine-rich loop that we hypothesize enables direct transfer of Zn from AtZNG1 to AtMAP1A during GTP hydrolysis. Based on proteomics and transcriptomics, loss of this ancient and conserved mechanism has pleiotropic consequences impacting the expression of hundreds of genes, including those involved in photosynthesis and vesicle transport. Members of the plant-specific family of NMCs, ZNG2A1 (AT1G80480) and ZNG2A2 (AT1G15730), are also required during Zn deficiency, but their target protein(s) remain to be discovered. RNA-seq analyses reveal wide-ranging impacts across the cell when the genes encoding these plastid-localized NMCs are disrupted.

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Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium

Liu,

Urzica,

Gallaher

et al. 2024

Photosynth Res

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Trace metal nutrition and response to deficiency

Cited by 4 publications

References 190 publications

Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium

Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium

Two related families of metal transferases, ZNG1 and ZNG2, are involved in acclimation to poor Zn nutrition in Arabidopsis

Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium

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