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Wang J, Liang S, Xiang W, Dai H, Duan Y, Kang F, Chai T. A repeat region from the Brassica juncea HMA4 gene BjHMA4R is specifically involved in Cd 2+ binding in the cytosol under low heavy metal concentrations. BMC PLANT BIOLOGY 2019; 19:89. [PMID: 30819104 PMCID: PMC6394093 DOI: 10.1186/s12870-019-1674-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/07/2019] [Indexed: 05/31/2023]
Abstract
BACKGROUND HMA4 transporters are involved in the transport and binding of divalent heavy metals (Cd, Zn, Pb [lead] and Co [cobalt]). In general, as efflux pumps, HMA4 transporters can increase the heavy metal tolerance of yeast and Escherichia coli. Additional research has shown that the C-terminus of HMA4 contains a heavy metal-binding domain and that heterologous expression of a portion of peptides from this C-terminal domain in yeast provides a high level of Cd tolerance and Cd hyperaccumulation. RESULTS We cloned BjHMA4 from Brassica juncea, and quantitative real-time PCR analysis revealed that BjHMA4 was upregulated by Zn and Cd in the roots, stems and leaves. Overexpression of BjHMA4 dramatically affects Zn/Cd distribution in rice and wheat seedlings. Interestingly, BjHMA4 contains a repeat region named BjHMA4R within the C-terminal region; this repeat region is not far from the last transmembrane domain. We further characterized the detailed function of BjHMA4R via yeast and E. coli experiments. Notably, BjHMA4R greatly and specifically improved Cd tolerance, and BjHMA4R transformants both grew on solid media that contained 500 μM CdCl2 and presented improved Cd accumulation (approximately twice that of wild-type [WT] strains). Additionally, visualization via fluorescence microscopy indicated that BjHMA4R clearly localizes in the cytosol of yeast. Overall, these findings suggest that BjHMA4R specifically improves Cd tolerance and Cd accumulation in yeast by specifically binding Cd2+ in the cytosol under low heavy metal concentrations. Moreover, similar results in E. coli experiments corroborate this postulation. CONCLUSION BjHMA4R can specifically bind Cd2+ in the cytosol, thereby substantially and specifically improving Cd tolerance and accumulation under low heavy metal concentrations.
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Affiliation(s)
- Jianwu Wang
- Shaanxi Key Laboratory of Ecological Restoration in Shanbei Mining Area, Yulin University, Yulin, 719000 Shaanxi China
| | - Shuang Liang
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Weiwei Xiang
- Shaanxi Key Laboratory of Ecological Restoration in Shanbei Mining Area, Yulin University, Yulin, 719000 Shaanxi China
| | - Huiping Dai
- College of Biological Science and Engineering, Shaanxi University of Technology, Hanzhong, Shaanxi 723001 People’s Republic of China
| | - Yizhong Duan
- Shaanxi Key Laboratory of Ecological Restoration in Shanbei Mining Area, Yulin University, Yulin, 719000 Shaanxi China
| | - Furen Kang
- Shaanxi Key Laboratory of Ecological Restoration in Shanbei Mining Area, Yulin University, Yulin, 719000 Shaanxi China
| | - Tuanyao Chai
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
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Zhang XY, Zhang X, Zhang Q, Pan XX, Yan LC, Ma XJ, Zhao WZ, Qi XT, Yin LP. Zea mays Fe deficiency-related 4 (ZmFDR4) functions as an iron transporter in the plastids of monocots. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:147-163. [PMID: 28103409 DOI: 10.1111/tpj.13482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 01/02/2017] [Accepted: 01/09/2017] [Indexed: 05/25/2023]
Abstract
Iron (Fe)-homeostasis in the plastids is closely associated with Fe transport proteins that prevent Fe from occurring in its toxic free ionic forms. However, the number of known protein families related to Fe transport in the plastids (about five) and the function of iron in non-green plastids is limited. In the present study, we report the functional characterization of Zea mays Fe deficiency-related 4 (ZmFDR4), which was isolated from a differentially expressed clone of a cDNA library of Fe deficiency-induced maize roots. ZmFDR4 is homologous to the bacterial FliP superfamily, coexisted in both algae and terrestrial plants, and capable of restoring the normal growth of the yeast mutant fet3fet4, which possesses defective Fe uptake systems. ZmFDR4 mRNA is ubiquitous in maize and is inducible by iron deficiency in wheat. Transient expression of the 35S:ZmFDR4-eGFP fusion protein in rice protoplasts indicated that ZmFDR4 maybe localizes to the plastids envelope and thylakoid. In 35S:c-Myc-ZmFDR4 transgenic tobacco, immunohistochemistry and immunoblotting confirmed that ZmFDR4 is targeted to both the chloroplast envelope and thylakoid. Meanwhile, ultrastructure analysis indicates that ZmFDR4 promotes the density of plastids and accumulation of starch grains. Moreover, Bathophenanthroline disulfonate (BPDS) colorimetry and inductively coupled plasma mass spectrometry (ICP-MS) indicate that ZmFDR4 is related to Fe uptake by plastids and increases seed Fe content. Finally, 35S:c-Myc-ZmFDR4 transgenic tobacco show enhanced photosynthetic efficiency. Therefore, the results of the present study demonstrate that ZmFDR4 functions as an iron transporter in monocot plastids and provide insight into the process of Fe uptake by plastids.
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Affiliation(s)
- Xiu-Yue Zhang
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xi Zhang
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Qi Zhang
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xiao-Xi Pan
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Luo-Chen Yan
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xiao-Juan Ma
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Wei-Zhong Zhao
- Institute of Mathematics and Interdisciplinary Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xiao-Ting Qi
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Li-Ping Yin
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
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Li S, Zhang X, Zhang XY, Xiao W, Berry JO, Li P, Jin S, Tan S, Zhang P, Zhao WZ, Yin LP. Expression ofMalus xiaojinensisIRT1 (MxIRT1) protein in transgenic yeast cells leads to degradation through autophagy in the presence of excessive iron. Yeast 2015; 32:499-517. [DOI: 10.1002/yea.3075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 04/04/2015] [Accepted: 04/06/2015] [Indexed: 02/02/2023] Open
Affiliation(s)
- Shuang Li
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
| | - Xi Zhang
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
| | - Xiu-Yue Zhang
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
| | - Wei Xiao
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
- Department of Microbiology and Immunology; University of Saskatchewan; Saskatoon SK Canada
| | - James O. Berry
- Department of Biological Sciences; State University of New York; Buffalo NY USA
| | - Peng Li
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
| | - Si Jin
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
| | - Song Tan
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
| | - Peng Zhang
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
| | - Wei-Zhong Zhao
- Institute of Mathematics and Interdisciplinary Sciences; Capital Normal University; Beijing People's Republic of China
| | - Li-Ping Yin
- College of Life Sciences; Capital Normal University; Beijing People's Republic of China
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Li S, Pan XX, Berry JO, Wang Y, Ma S, Tan S, Xiao W, Zhao WZ, Sheng XY, Yin LP. OsSEC24, a functional SEC24-like protein in rice, improves tolerance to iron deficiency and high pH by enhancing H(+) secretion mediated by PM-H(+)-ATPase. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 233:61-71. [PMID: 25711814 DOI: 10.1016/j.plantsci.2015.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/29/2014] [Accepted: 01/01/2015] [Indexed: 05/16/2023]
Abstract
Iron is abundant in the soil, but its low solubility in neutral or alkaline soils limits its uptake. Plants can rely on rhizosphere acidification to increase iron solubility. OsSEC27p was previously found to be a highly up-regulated gene in iron-deficient rice roots. Here, pH-dependent complementation assays using yeast mutants sec24Δ/SEC24 and sec27Δ/SEC27 showed that OsSEC27 could functionally complement SEC24 but not SEC27 in yeast; thus, it was renamed as OsSEC24. We found that OsSEC24-transgenic tobacco plants increased the length and number of roots under iron deficiency at pH 8.0. To explore how OsSEC24 confers tolerance to iron deficiency, we utilized transgenic tobacco, rice and rice protoplasts. H(+) flux measurements using Non-invasive Micro-test Technology (NMT) indicated that the transgenic OsSEC24 tobacco and rice enhanced H(+) efflux under iron deficiency. Conversely, the application of plasma membrane PM-H(+)-ATPase inhibitor vanadate elucidated that H(+) secretion increased by OsSEC24 was mediated by PM-H(+)-ATPase. OsPMA2 was used as a representative of iron deficiency-responsive PM-H(+)-ATPases in rice root via RT-PCR analysis. In transgenic rice protoplasts OsPMA2 was packaged into OsSEC24 vesicles after export from the ER through confocal-microscopy observation. Together, OsSEC24 vesicles, along with PM-H(+)-ATPases stimulate roots formation under iron deficiency by enhancing rhizosphere acidification.
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Affiliation(s)
- Shuang Li
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - Xiao-Xi Pan
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - James O Berry
- Department of Biological Sciences, State University of New York, Buffalo, NY 14260, USA
| | - Yi Wang
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - Shuang Ma
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - Song Tan
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - Wei Xiao
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - Wei-Zhong Zhao
- Institute of Mathematics and Interdisciplinary Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - Xian-Yong Sheng
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China
| | - Li-Ping Yin
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Beijing 100048, China.
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Over-expression of the MxIRT1 gene increases iron and zinc content in rice seeds. Transgenic Res 2014; 24:109-22. [PMID: 25099285 DOI: 10.1007/s11248-014-9822-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 07/28/2014] [Indexed: 01/01/2023]
Abstract
Iron and zinc are essential in plant and human nutrition. Iron deficiency has been one of the causes of human mortality, especially in developing countries with high rice consumption. MxIRT1 is a ferrous transporter that has been screened from an iron-efficient genotype of the apple tree, Malus xiaojinensis Cheng et Jiang. In order to produce Fe-biofortified rice with MxIRT1 to solve the Fe-deficiency problem, plant expression vectors of pCAMBIA1302-MxIRT1:GFP and pCAMBIA1302-anti MxIRT1:GFP were constructed that led to successful production of transgenic rice. The transgenic plant phenotypes showed that the expression of endogenous OsIRT1 was suppressed by anti-MxIRT1 in antisense lines that acted as an opposing control, while sense lines had a higher tolerance under Zn- and Fe-deficient conditions. The iron and zinc concentration in T3 seeds increased by three times in sense lines when compared to the wild type. To understand the MxIRT1 cadmium uptake, the MxIRT1 cadmium absorption trait was compared with AtIRT1 and OsIRT1 in transgenic rice protoplasts, and it was found that MxIRT1 had the lowest Cd uptake capacity. MxIRT1 transgenic tobacco-cultured bright yellow-2 (BY-2) cells and rice lines were subjected to different Fe conditions and the results from the non-invasive micro-test technique showed that iron was actively transported compared to cadmium as long as iron was readily available in the environment. This suggests that MxIRT1 is a good candidate gene for plant Fe and Zn biofortification.
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Naren, Zhang P, Ma D, Wang Y, Li S, Yin L. Overexpression of OsDPR, a novel rice gene highly expressed under iron deficiency, suppresses plant growth. SCIENCE CHINA. LIFE SCIENCES 2012; 55:1082-91. [PMID: 23233223 DOI: 10.1007/s11427-012-4414-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 10/29/2012] [Indexed: 10/27/2022]
Abstract
Preliminary microarray analysis of cDNA from rice roots revealed an up-regulated transcript that was highly expressed in a five-day iron deficiency treatment. The entire sequence of this gene was determined by bioinformatics analysis. There were no proteins with significant levels of similarity detected in public databases. This novel gene with unknown biological function was designated as OsDPR (dwarf phenotype-related gene). We constructed a stable plant expression vector pCAMBIA1302-OsDPR::GFP and produced transgenic tobacco plants. The phenotypes suggested that OsDPR restrained the growth of transformed plants. To understand the mechanisms of this suppression effect, cell size and number were compared between transformants and wild-type plants. The cell proliferation rate was lower in OsDPR transgenic BY-2 cells than in wild-type cells, but OsDPR expression did not affect cell size. Moreover, the cell division-related gene CyclinD2.1, which is involved in plant growth, was down-regulated in transgenic tobacco plants. These findings suggested that the novel iron-regulated gene OsDPR is responsible for the nanism phenotype of transgenic seedlings because of the inhibition of plant cell proliferation.
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Affiliation(s)
- Naren
- College of Life Science, Capital Normal University, Beijing 100048, China
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