Arsenic translocation in rice investigated using radioactive 73As tracer

Zhao, Fang‐Jie; Stroud, Jacqueline L.; Khan, Md. Asaduzzaman; McGrath, Steve P.

doi:10.1007/s11104-011-0926-4

Cited by 68 publications

(32 citation statements)

References 40 publications

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“…Thus, the companion cells possibly provide the most important storage capacity of As in rice aboveground tissues, implying that the biosynthesis of phytochelatins and the vacuolar transport of As(III)-phytochelatin complexes are likely to be much enhanced in this cell type. This distribution pattern also supports the notion that inorganic As is transported to the grain mainly via the phloem [40,41], although with a restricted mobility, presumably because of the vacuolar sequestration. In rice grain, information obtained largely through fluorescence tomography indicates that inorganic As [mainly As(III)] accumulates preferentially in the ovular vascular traces (OVTs) (Figure 2F), which are the conducting tissues transporting nutrients and water to the grain [42][43][44].…”

Section: Trends In Plant Sciencesupporting

confidence: 83%

“…NanoSIMS has been used to reveal the uptake and competition between rhizosphere microorganisms and plant roots for 15 N labeled ammonium [55,56]. Pulsing cut stems of bean (Phaseolus vulgaris) plants with 26 Mg, 41 K, 44 Ca, and H 2 18 O and using cryo-SIMS to image their distribution at different times revealed a rapid exchange of cations between xylem vessels and the adjacent xylem parenchyma cells, and a slow exchange with cambium and phloem; the three cations also exhibited different exchange kinetics [57,58]. In these studies, samples were shock-frozen in melting propane, fractured, and analyzed under cryo-conditions, thus preserving the cellular structure and in situ element distribution.…”

Section: Trends In Plant Sciencementioning

confidence: 99%

See 1 more Smart Citation

Imaging element distribution and speciation in plant cells

Zhao

Moore

Lombi

et al. 2014

Trends in Plant Science

Self Cite

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 Sciencesupporting

confidence: 83%

Section: Trends In Plant Sciencementioning

confidence: 99%

Imaging element distribution and speciation in plant cells

Zhao

Moore

Lombi

et al. 2014

Trends in Plant Science

Self Cite

138

103

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“…Carey et al (2011) fed excised flag leaves with As(III), and found As in the flag leaf, while no As was detected in the grain. In contrast, Zhao et al (2012) exposed excised flag leaves to radioactive 73 As-labeled As(III) and found 2%-3% of the total absorbed As was transported to the grain. The different results between the studies were explained by the higher sensitivity of the 73 As method.…”

Section: As Species In Polished Ricementioning

confidence: 97%

“…As(III) transport into rice grain occurs nearly exclusively via the phloem, since the grain As level was reduced by 90% to 97% when phloem at the base of the panicle was destroyed (Carey et al, 2010;Zhao et al, 2012). As(III) may be loaded into the phloem in the leaves, especially the flag leaf, as well as in the stem nodes by xylem-to-phloem transfer.…”

Section: As Species In Polished Ricementioning

confidence: 99%

Silicon decreases the arsenic level in rice grain by limiting arsenite transport

Fleck

Mattusch

Schenk

2013

Z. Pflanzenernähr. Bodenk.

125

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Silicon (Si) reduces arsenic (As) levels in rice shoot and grain. However, the underlying mechanisms remain unclear. In this study, we examined the effect of Si application to three rice paddy soils on the dynamics of Si, iron (Fe), phosphorus (P), and As in the soil solution, As accumulation in rice straw, flag leaf, husk, brown rice, and polished rice, and on As speciation in polished rice. Silicon application to soil increased the concentrations of Si, Fe, As, and P in the soil solution, while the redox potential was unaffected. Arsenic concentrations of straw, flag leaf, and husk were reduced by half by Si application, while As concentrations of brown and polished rice were decreased by 22%. The main As species in polished rice was arsenite, As(III), with a fraction of 70%, followed by dimethylarsinic acid (DMA) and arsenate, As(V), with 24% and 6%, respectively. Silicon application to the soil did not affect DMA or As(V) concentration of polished rice, while the As(III) concentration was reduced by 33%. These results confirm that Si reduces As(III) uptake and translocation into the shoot. Furthermore, data indicate that decrease of As concentration of polished rice is due to decreased As(III) transport into grain. Possible underlying mechanisms are discussed.

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“…Wu et al 26 (2012) also showed that there was no significant difference between arsenite and arsenate treatments in As accumulation in rice roots. However, there was a significant difference in As accumulation in shoots between these two As treatments (P<0.001) and this may be due to different transportation mechanisms from root to shoot between arsenite and arsenate (Zhao et al, 2012) 48 . Aerated treatments showed significantly lower As accumulations in roots compared to stagnant treatments (Table 2).…”

Section: Disscussionmentioning

confidence: 88%

Oxic and anoxic conditions affect arsenic (As) accumulation and arsenite transporter expression in rice

Liu

Xue

et al. 2017

Chemosphere

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Arsenic (As) exposure from rice consumption has now become a global health issue.It is known that arsenite and silicic (Si) acid share the same transporters, as do arsenate and phosphate (Pi) in rice. Growing rice aerobically, rather than in waterlogged conditions, may significantly reduce As accumulation in rice. This study aimed to investigate the effects of oxidation status on Si and Pi transporter expressions and to determine the effect of oxidation status on As uptake, translocation and speciation in four different rice genotypes. The study includes two hybrid genotypes, Xiangfengyou9 and Shenyou9586, and two conventional indica subspecies, Xiangwanxian17 and Xiangwanxian12. Results showed that oxidative treatments have significant effects on root length (P<0.001) and root weight (P<0.05). With the same As treatment, total As concentrations in roots were dramatically lower in oxic treatments, (82.4 to 242.8 mg/kg) compared to anoxic treatments (142.9 to 265.4 mg/kg) (P<0.001). Furthermore, As treatments had a significant effect on the total As concentrations of shoots (P<0.001), with higher As contents in arsenite treatments compared to arsenate treatments. In arsenate treatments, root arsenite concentrations in anoxic treatments were 1.5-2.5-fold higher than that in oxic treatments. The relative abundance of Lsi1 and Lsi2 expressions displayed a trend of down-regulation in oxic treatments compared to anoxic treatments, especially significantly different for Xiangwanxian17, Xiangwanxian12 in Lsi1 expressions, and Xiangfengyou9, Shenyou9586, Xiangwanxian17 in Lsi2 expressions (P<0.05). The relative abundance of phosphate transporter expressions also presented a trend of down-regulation in oxic treatments compared to anoxic treatments, especially significantly different for Shenyou9586, Xiangwanxian17, Xiangwanxian12 in inorganic phosphate transporter expressions, and Xiangwanxian17 in phosphate:H + symporter family protein expression (P<0.05). Different As treatment did not exert significant differences in Lsi1, Lsi2 and Pi transporters' expressions. Additionally, there were no significant genotypic differences on Lsi1, Lsi2 and phosphate transporters' expressions regardless of hybrid or conventional genotypes. The arsenic transporter expression level differences between oxic and anoxic conditions may be a possible reason for low As accumulation in rice growing in oxic compared to anoxic conditions; this may be a potential route to reduce the risk of As entering the food chain.

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Arsenic translocation in rice investigated using radioactive 73As tracer

Cited by 68 publications

References 40 publications

Imaging element distribution and speciation in plant cells

Imaging element distribution and speciation in plant cells

Silicon decreases the arsenic level in rice grain by limiting arsenite transport

Oxic and anoxic conditions affect arsenic (As) accumulation and arsenite transporter expression in rice

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