Iron and zinc complexation in wild-type and ferritin-expressing wheat grain: implications for mineral transport into developing grain

Neal, Andrew L.; Geraki, Kalotina; Borg, Søren; Quinn, Paul D.; Mosselmans, J. Frederick W.; Brinch-Pedersen, Henrik; Shewry, Peter R.

doi:10.1007/s00775-013-1000-x

Cited by 44 publications

(51 citation statements)

References 39 publications

(50 reference statements)

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“…Synchrotron-based techniques for analyzing elemental distribution and speciation in plant tissues. The images of cowpea root, wheat grain, and rice grain are reproduced, with permission, from [37,75,84]. The rice node image is based on unpublished data from the authors.…”

Section: Trends In Plant Sciencementioning

confidence: 99%

“…19,No. 3 than two P atoms, whereas Zn was coordinated tetrahedrally by four O atoms and approximately 1.5 P atoms [75]. In the case of Cu, Cu(II) is reduced to Cu(I) and coordinated to S, possibly as Cu(I)-metallothionein complexes in tomato (Solanum lycopersicum) and oat (Avena sativa) plants [76] and in alpine pennycress (Noccaea caerulescens; formerly Thlaspi caerulescens), which hyperaccumulates Zn and Cd but not Cu [77].…”

Section: Reviewmentioning

confidence: 99%

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Imaging element distribution and speciation in plant cells

Zhao

Moore

Lombi

et al. 2014

Trends in Plant Science

138

103

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To maintain cellular homeostasis, concentrations, chemical speciation, and localization of mineral nutrients and toxic trace elements need to be regulated. Imaging the cellular and subcellular localization of elements and measuring their in situ chemical speciation are challenging tasks that can be undertaken using synchrotronbased techniques, such as X-ray fluorescence and X-ray absorption spectrometry, and mass spectrometry-based techniques, such as secondary ion mass spectrometry and laser-ablation inductively coupled plasma mass spectrometry. We review the advantages and limitations of these techniques, and discuss examples of their applications, which have revealed highly heterogeneous distribution patterns of elements in different cell types, often varying in chemical speciation. Combining these techniques with molecular genetic approaches can unravel functions of genes involved in element homeostasis. Spatial and chemical information of mineral element homeostasisPlants take up a range of mineral elements from the soil, some of which are essential for growth, whereas others are non-essential [1]. Deficiencies of essential elements are a major limiting factor for crop production in many areas worldwide, whereas excessive accumulation of both essential and non-essential elements can lead to phytotoxicity [1]. Accumulation of some elements, such as cadmium (Cd) [2] and arsenic (As) [3], in the edible parts of crops may pose a significant risk to human health well before phytotoxicity occurs. By contrast, there is a need to increase essential micronutrients, such as iron (Fe) and zinc (Zn), in plantbased foods to alleviate their deficiencies in humans [4]. Plant nutrition research aims to understand how minerals are acquired, transported, distributed, stored, and used in plants. This knowledge is important not only for sustainable agricultural production but also for ensuring the nutritional quality and safety of agricultural products [5].Analyses of total elemental concentrations can now be performed using high-throughput platforms to reveal the ionomic profile (see Glossary) of plant tissues [6]. Although the total concentrations of minerals can provide information about the capacity for uptake and translocation, it is well recognized that minerals are distributed heterogeneously across different cell types [7]. Not only may the total concentrations vary at the tissue, cellular, and subcellular scales but also the chemical speciation of minerals may vary. This spatial information is crucial for understanding the homeostasis of minerals, particularly how different cell types and, fundamentally, different genes function in controlling the distribution, complexation, and storage of minerals, and how these processes vary among diverse plant species in the ecophysiological context.A range of techniques are available for mapping element distribution at various spatial scales. Traditional methods, such as energy-dispersive X-ray microanalysis (EDX) and proton (particle)-induced X-ray emission (PIXE), have been u...

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Section: Trends In Plant Sciencementioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

Imaging element distribution and speciation in plant cells

Zhao

Moore

Lombi

et al. 2014

Trends in Plant Science

138

103

View full text Add to dashboard Cite

show abstract

“…Usually zinc is considered as a “borderline” metal, which does not consistently act either “hard” (not very polarizable) or “soft” (highly polarizable); and hence does not have a strong preference for coordinating with either oxygen or nitrogen or sulphur atoms [5], [6]. Speciation of Zn in barley and wheat grain is not well understood although several hypotheses exist regarding the association with S or O atoms in the aleurone layers of the grain [19], [74]. B-hordein is known to be localized mainly in the sub-aleurone layer of the grain.…”

Section: Discussionmentioning

confidence: 99%

Effects of Zn Fertilization on Hordein Transcripts at Early Developmental Stage of Barley Grain and Correlation with Increased Zn Concentration in the Mature Grain

2014

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Zinc deficiency is causing malnutrition for nearly one third of world populations. It is especially relevant in cereal-based diets in which low amounts of mineral and protein are present. In biological systems, Zn is mainly associated with protein. Cereal grains contain the highest Zn concentration during early developmental stage. Although hordeins are the major storage proteins in the mature barley grain and suggested to be involved in Zn binding, very little information is available regarding the Zn fertilization effects of hordein transcripts at early developmental stage and possible incorporation of Zn with hordein protein of matured grain. Zinc fertilization experiments were conducted in a greenhouse with barley cv. Golden Promise. Zn concentration of the matured grain was measured and the results showed that the increasing Zn fertilization increased grain Zn concentration. Quantitative real time PCR showed increased level of total hordein transcripts upon increasing level of Zn fertilization at 10 days after pollination. Among the hordein transcripts the amount of B-hordeins was highly correlated with the Zn concentration of matured grain. In addition, protein content of the matured grain was analysed and a positive linear relationship was found between the percentage of B-hordein and total grain Zn concentration while C-hordein level decreased. Zn sensing dithizone assay was applied to localize Zn in the matured grain. The Zn distribution was not limited to the embryo and aleurone layer but was also present in the outer part of the endosperm (sub-aleurone layers) which known to be rich in proteins including B-hordeins. Increased Zn fertilization enriched Zn even in the endosperm. Therefore, the increased amount of B-hordein and decreased C-hordein content suggested that B-hordein upregulation or difference between B and C hordein could be one of the key factors for Zn biofortification of cereal grains due to the Zn fertilization.

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“…Bran is rich in both vitamins and minerals, with the majority of these nutrients residing in the aleurone component (Neal et al . ; Wu et al . ; Latunde‐Dada et al .…”

Section: Cereals As An Important Source Of Mineralsmentioning

confidence: 99%

Enhancing mineral bioavailability from cereals: Current strategies and future perspectives

et al. 2018

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Inadequate intake of essential minerals such as iron and zinc is a public health concern in the UK, particularly for girls and young women. Approximately 30% and 50% of the zinc and iron, respectively, in the UK diet is provided by cereals. In wheat, most of the iron and zinc is contained within the aleurone cell layer; however, aleurone is removed during processing of wheat into white flour. While elemental iron powder is added back into white flour at the milling stage, there is no restoration of zinc. Elemental iron powder has very low bioavailability, and therefore, in our current Biotechnology and Biological Sciences Research Council Diet and Health Research Industry Club‐funded project, we are investigating the potential use of aleurone as a bioavailable source of minerals that could be added to wheat‐based foods. This work has relevance for the food industry and may establish the use of aleurone as a functional food ingredient for fortification of a range of cereal‐based food products.

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Iron and zinc complexation in wild-type and ferritin-expressing wheat grain: implications for mineral transport into developing grain

Cited by 44 publications

References 39 publications

Imaging element distribution and speciation in plant cells

Imaging element distribution and speciation in plant cells

Effects of Zn Fertilization on Hordein Transcripts at Early Developmental Stage of Barley Grain and Correlation with Increased Zn Concentration in the Mature Grain

Enhancing mineral bioavailability from cereals: Current strategies and future perspectives

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