Chin Bull Bot ›› 2018, Vol. 53 ›› Issue (4): 451-455.doi: 10.11983/CBB18056

• COMMENTARIES • Previous Articles     Next Articles

A Defensin-like Protein Regulates Cadmium Accumulation in Rice

Huang Xinyuan*(), Zhao Fangjie   

  1. State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2018-03-08 Accepted:2018-03-30 Online:2018-09-11 Published:2018-07-01
  • Contact: Huang Xinyuan
  • About author:† These authors contributed equally to this paper


Cadmium (Cd) is a highly toxic heavy metal that threatens human health. Rice is one of food crops that can accumulate Cd in the grain to levels that are unsafe for human consumption. With increasing contamination of heavy metals in paddy soils in China, considerable proportions of rice grain produced in some areas of southern China exceed the 0.2 mg·kg-1 Cd limit of the Chinese food standard, which causes widespread public concern. Molecular breeding of rice varieties that accumulate Cd in straw for removing Cd from paddy soil while producing safe grain is one of the strategies for phytoremediation of contaminated soils. Recently, Luo et al. identified a quantitative trait locus CAL1 in rice that specifically regulates the accumulation of Cd in leaves. CAL1 encodes a defensin-like protein that can chelate Cd in the cytosol and facilitates Cd secretion from xylem parenchyma cells into xylem vessels for long-distance transport. The chelation of Cd to CAL1 appears to prevent Cd from being loaded into the phloem for transport to rice grain. Thus, CAL1 does not affect the accumulation of Cd in rice grain. These findings shed light on understanding the molecular mechanism of Cd translocation and allocation in rice and provide a molecular tool to breed rice varieties that may be used to remove Cd from the soil without affecting grain Cd concentration.

Key words: rice, cadmium, phytoremediation, defensin protein

Figure 1

Schematic diagram of the uptake and transport of Cd in rice rootsThe uptake of Cd into rice roots is mediated by OsNRAMP5, which is also responsible for the transport of Cd from cortex cells into endodermis. Part of Cd is then sequestered into vacuoles by OsHMA3. In xylem parenchyma cells, Cd is chelated with CAL1 in the cytosol and then is secreted into the xylem vessels for long-distance transport to shoots. CAL1 is also expressed in exodermis, where CAL1 is also able to chelate Cd and potentially facilitates the Cd secretion from exodermis into cortex cells. However, it is still not clear whether transporters or vesicular trafficking pathways are responsible for translocating the CAL1-Cd complex across the plasma membrane."

1 环境保护部和国土资源部 (2014). 全国土壤污染状况调查公报. .
2 Das N, Bhattacharya S, Bhattacharyya S, Maiti MK (2017). Identification of alternatively spliced transcripts of rice phytochelatin synthase 2 gene OsPCS2 involved in miti- gation of cadmium and arsenic stresses. Plant Mol Biol 94, 167-183.
3 Du Y, Hu XF, Wu XH, Shu Y, Jiang Y, Yan XJ (2013). Affects of mining activities on Cd pollution to the paddy soils and rice grain in Hunan province, Central South China.Environ Monit Assess 185, 9843-9856.
4 Ishikawa S, Ishimaru Y, Igura M, Kuramata M, Abe T, Senoura T, Hase Y, Arao T, Nishizawa NK, Nakanishi H (2012). Ion-beam irradiation, gene identification, and marker- assisted breeding in the development of low-cadmium rice.Proc Natl Acad Sci USA 109, 19166-19171.
5 Ishimaru Y, Takahashi R, Bashir K, Shimo H, Senoura T, Sugimoto K, Ono K, Yano M, Ishikawa S, Arao T, Nakanishi H, Nishizawa NK (2012). Characterizing the role of rice NRAMP5 in manganese, iron and cadmium transport.Sci Rep 2, 286.
6 Luo JS, Huang J, Zeng DL, Peng JS, Zhang GB, Ma HL, Guan Y, Yi HY, Fu YL, Han B, Lin HX, Qian Q, Gong JM (2018). A defensin-like protein drives cadmium efflux and allocation in rice.Nat Commun 9, 645.
7 Miyadate H, Adachi S, Hiraizumi A, Tezuka K, Nakazawa N, Kawamoto T, Katou K, Kodama I, Sakurai K, Tak- ahashi H, Satoh-Nagasawa N, Watanabe A, Fujimura T, Akagi H (2011). OsHMA3, a P1B-type of ATPase affects root-to-shoot cadmium translocation in rice by mediating efflux into vacuoles.New Phytol 189, 190-199.
8 Sasaki A, Yamaji N, Yokosho K, Ma JF (2012). Nramp5 is a major transporter responsible for manganese and cad- mium uptake in rice.Plant Cell 24, 2155-2167.
9 Song Y, Wang Y, Mao WF, Sui HX, Yong L, Yang DJ, Jiang DG, Zhang L, Gong YY (2017). Dietary cadmium expo- sure assessment among the Chinese population.PLoS One 12, e0177978.
10 Tang L, Mao BG, Li YK, Lv QM, Zhang LP, Chen CY, He HJ, Wang WP, Zeng XF, Shao Y, Pan YL, Hu YY, Peng Y, Fu XQ, Li HQ, Xia ST, Zhao BR (2017). Knockout of OsNramp5 using the CRISPR/Cas9 system produces low Cd-accumulating indica rice without compromising yield.Sci Rep 7, 14438.
11 Ueno D, Yamaji N, Kono I, Huang CF, Ando T, Yano M, Ma JF (2010). Gene limiting cadmium accumulation in rice.Proc Natl Acad Sci USA 107, 16500-16505.
12 Yan JL, Wang PT, Wang P, Yang M, Lian XM, Tang Z, Huang CF, Salt DE, Zhao FJ (2016). A loss-of-function allele of OsHMA3 associated with high cadmium accu- mulation in shoots and grain of Japonica rice cultivars. Plant Cell Environ 39, 1941-1954.
13 Yang M, Zhang YY, Zhang LJ, Hu JT, Zhang X, Lu K, Dong HX, Wang DJ, Zhao FJ, Huang CF, Lian XM (2014). OsNRAMP5 contributes to manganese translocation and distribution in rice shoots.J Exp Bot 65, 4849-4861.
14 Zhao FJ, Ma YB, Zhu YG, Tang Z, McGrath SP (2015). Soil contamination in China: current status and mitigation stra- tegies.Environ Sci Technol 49, 750-759.
15 Zhu HH, Chen C, Xu C, Zhu QH, Huang DY (2016). Effects of soil acidification and liming on the phytoavailability of cadmium in paddy soils of central subtropical China.En- viron Pollut 219, 99-106.
[1] . A New Progress of Green Revolution: Epigenetic Modification Dual-regulated by Gibberellin and Nitrogen Supply Contributes to Breeding of High Yield and Nitrogen Use Efficiency Rice [J]. Chin Bull Bot, 2020, 55(1): 0-0.
[2] Zhang Tong,Guo Yalu,Chen Yue,Ma Jinjiao,Lan Jinping,Yan Gaowei,Liu Yuqing,Xu Shan,Li Liyun,Liu Guozhen,Dou Shijuan. Expression Characterization of Rice OsPR10A and Its Function in Response to Drought Stress [J]. Chin Bull Bot, 2019, 54(6): 711-722.
[3] Zhang Shuo, Wu Changyin. Long Noncoding RNA Ef-cd Promotes Maturity Without Yield Penalty in Rice [J]. Chin Bull Bot, 2019, 54(5): 550-553.
[4] Li Weitao, He Min, Chen Xuewei. Discovery of ZmFBL41 Chang7-2 as A Key Weapon against Banded Leaf and Sheath Blight Resistance in Maize [J]. Chin Bull Bot, 2019, 54(5): 547-549.
[5] Tian Huaidong, Li Jing, Tian Baohua, Niu Pengfei, Li Zhen, Yue Zhongxiao, Qu Yajuan, Jiang Jianfang, Wang Guangyuan, Cen Huihui, Li Nan, Yan Feng. Method for N-methyl-N-nitrosourea Mutagenesis on Hermaphroditic Germ Cells of Rice [J]. Chin Bull Bot, 2019, 54(5): 625-633.
[6] Zhou Chun, Jiao Ran, Hu Ping, Lin Han, Hu Juan, Xu Na, Wu Xianmei, Rao Yuchun, Wang Yuexing. Gene Mapping and Candidate Gene Analysis of Rice Early Senescence Mutant LS-es1 [J]. Chin Bull Bot, 2019, 54(5): 606-619.
[7] Liu Dongfeng, Tang Yongyan, Luo Shengtao, Luo Wei, Li Zhitao, Chong Kang, Xu Yunyuan. Identification of Chilling Tolerance of Rice Seedlings by Cold Water Bath [J]. Chin Bull Bot, 2019, 54(4): 509-514.
[8] Liu Jin, Yao Xiaoyun, Yu Liqin, Li Hui, Zhou Huiying, Wang Jiayu, Li Maomao. Detection and Analysis of Dynamic Quantitative Trait Loci at Three Years for Seed Storability in Rice (Oryza sativa) [J]. Chin Bull Bot, 2019, 54(4): 464-473.
[9] Cheng Xinjie, Yu Hengxiu, Cheng Zhukuan. Protocols for Analyzing Rice Meiotic Chromosomes [J]. Chin Bull Bot, 2019, 54(4): 503-508.
[10] Wang Xiaolin,Wang Ertao. NRT1.1B Connects Root Microbiota and Nitrogen Use in Rice [J]. Chin Bull Bot, 2019, 54(3): 285-287.
[11] Li Lulu, Yin Wenchao, Niu Mei, Meng Wenjing, Zhang Xiaoxing, Tong Hongning. Functional Analysis of Brassinosteroids in Salt Stress Responses in Rice [J]. Chin Bull Bot, 2019, 54(2): 185-193.
[12] Chen Lin,Lin Yan,Chen Pengfei,Wang Shaohua,Ding Yanfeng. Effect of Iron Deficiency on the Protein Profile of Rice (Oryza sativa) Phloem Sap [J]. Chin Bull Bot, 2019, 54(2): 194-207.
[13] Ye Wenlan,Ma Guolan,Yuan liyanan,Zheng Shiyi,Cheng Linqiao,Fang Yuan,Rao Yuchun. Research Progress on Pathogenic Characteristics and Resistance of Bacterial Panicle Blight of Rice [J]. Chin Bull Bot, 2019, 54(2): 277-283.
[14] Yang Dewei,Wang Mo,Han Libo,Tang Dingzhong,Li Shengping. Progress of Cloning and Breeding Application of Blast Resistance Genes in Rice and Avirulence Genes in Blast Fungi [J]. Chin Bull Bot, 2019, 54(2): 265-276.
[15] Zhu Li, Qian Qian. Astaxanthin Functional Rice: New Idea of Biofortification, New Perspectives for High-quality Rice Breeding [J]. Chin Bull Bot, 2019, 54(1): 4-8.
Full text



[1] Hu Shi-yi. Fertilization in Plants IV. Fertilization Barriers Inoompalibilty[J]. Chin Bull Bot, 1984, 2(23): 93 -99 .
[2] JIANG Gao-Ming. On the Restoration and Management of Degraded Ecosystems: with Special Reference of Protected Areas in the Restoration of Degraded Lands[J]. Chin Bull Bot, 2003, 20(03): 373 -382 .
[3] . [J]. Chin Bull Bot, 1994, 11(专辑): 65 .
[4] . [J]. Chin Bull Bot, 1996, 13(专辑): 103 .
[5] ZHANG Xiao-Ying;YANG Shi-Jie. Plasmodesmata and Intercellular Trafficking of Macromolecules[J]. Chin Bull Bot, 1999, 16(02): 150 -156 .
[6] Chen Zheng. Arabidopsis thaliana as a Model Species for Plant Molecular Biology Studies[J]. Chin Bull Bot, 1994, 11(01): 6 -11 .
[7] . [J]. Chin Bull Bot, 1996, 13(专辑): 13 -16 .
[8] LEI Xiao-Yong HUANG LeiTIAN Mei-ShengHU Xiao-SongDAI Yao-Ren. Isolation and Identification of AOX (Alternative Oxidase) in ‘Royal Gala’ Apple Fruits[J]. Chin Bull Bot, 2002, 19(06): 739 -742 .
[9] Chunpeng Yao;Na Li. Research Advances on Abscisic Acid Receptor[J]. Chin Bull Bot, 2006, 23(6): 718 -724 .
[10] Li Wang, Qinqin Wang, Youqun Wang. Cytochemical Localization of ATPase and Acid Phosphatase in Minor Veins of the Leaf of Vicia faba During Different Developmental Stages[J]. Chin Bull Bot, 2014, 49(1): 78 -86 .