Zinc localization and speciation in rice grain under variable soil zinc deficiency

Shen，Yating1,2,3; Wiita，Elizabeth1,4; Nghiem，Athena A.1; Liu，Jingyu5; Haque，Ezazul6; Austin，Rachel N.4; Seng，Chheng Y.7; Phan，Kongkea7; Zheng，Yan1,5; Bostick，Benjamin C.1

2023

10.1007/s11104-023-06140-1

Plant and Soil   Impact Factor & Quartile

0032-079X

1573-5036

Background and aims: Rice accounts for around 20% of the calories consumed by humans. Essential nutrients like zinc (Zn) are crucial for rice growth and for populations relying on rice as a staple food. No well-established study method exists. As a result, we a lack a clear picture of the chemical forms of zinc in rice grain. Furthermore, we do not understand the effects of widespread and variable zinc deficiency in soils on the Zn speciation, and to a lesser extent, its concentration, in grain. Methods: The composition and Zn speciation of Cambodian rice grain is analyzed using synchrotron-based microprobe X-ray fluorescence (µ-XRF) and extended X-ray absorption fine-structure spectroscopy (EXAFS). We developed a method to quantify Zn species in different complexes based on the coordination numbers of Zn to oxygen and sulfur at characteristic bond lengths. Results: Zn levels in brown rice grain ranged between 15–30 mg kg and were not correlated to Zn availability in soils. 72%-90% of Zn in rice grains is present as Zn-phytate, generally not bioavailable, while smaller quantities of Zn are bound as labile nicotianamine complexes, Zn minerals like ZnCO or thiols. Conclusion: Zn speciation in rice grain is affected by Zn deficiency more than previously recognized. A majority of Zn was bound in phytate complexes in rice grain. Zinc phytate complexes were found in higher concentrations and also in higher proportions, in Zn-deficient soils, consistent with increased phytate production under Zn deficiency. Phytates are generally not bioavailable to humans, so low soil Zn fertility may not only impact grain yields, but also decrease the fraction of grain Zn bioavailable to human consumers. The potential impact of abundant Zn-phytate in environments deficient in Zn on human bioavailability and Zn deficiency requires additional research.

Bioaccessibility Bioavailability Micro-XRF Phytate Zn Zn deficiency Zn EXAFS

SCI

English

Others

National Science Foundation (NSF)["EAR 22-26647","EAR 1521356","ICR 1414131"] ; National Institute of Environmental Health Sciences["P42ES010349","P42ES033719"] ; Strategic Priority Research Program of Chinese Academy of Sciences[XDA20060402] ; National Natural Science Foundation of China[41877505] ; U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences[DE-AC02-76SF00515]

Agriculture ; Plant Sciences

Agronomy ; Plant Sciences ; Soil Science

WOS:001030498400001

SPRINGER

AGRICULTURAL SCIENCES

2-s2.0-85164793982

Scopus

1.Lamont-Doherty Earth Observatory of Columbia University,New York,61 Route 9W, Palisades,10964,United States
2.National Research Center for Geo-Analysis (NRCGA),Beijing,100037,China
3.Key Laboratory of Eco-Geochemistry,Ministry of Natural Resources of China,Beijing,100037,China
4.Department of Chemistry,Barnard College,New York,10027,United States
5.State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
6.IDGP in Human Toxicology and Department of Occupational and Environmental Health,University of Iowa,Iowa City,52242,United States
7.Department of Food Chemistry,Faculty of Science and Technology,International University,Phnom Penh,12101,Cambodia

Shen，Yating,Wiita，Elizabeth,Nghiem，Athena A.,et al. Zinc localization and speciation in rice grain under variable soil zinc deficiency[J]. Plant and Soil,2023,491(1-2).

Shen，Yating.,Wiita，Elizabeth.,Nghiem，Athena A..,Liu，Jingyu.,Haque，Ezazul.,...&Bostick，Benjamin C..(2023).Zinc localization and speciation in rice grain under variable soil zinc deficiency.Plant and Soil,491(1-2).

Shen，Yating,et al."Zinc localization and speciation in rice grain under variable soil zinc deficiency".Plant and Soil 491.1-2(2023).