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Regulatory mechanism of silicon in strengthening cadmium immobilization in the foliar cell wall of a grain low-cadmium rice line
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  • Jingyi Guo,
  • Daihua Ye,
  • Xizhou Zhang,
  • Huagang Huang,
  • Yongdong Wang,
  • Zicheng Zheng,
  • Tingxuan Li,
  • Haiying Yu
Jingyi Guo
Sichuan Agricultural University - Chengdu Campus
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Daihua Ye
Sichuan Agricultural University - Chengdu Campus
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Xizhou Zhang
Sichuan Agricultural University - Chengdu Campus
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Huagang Huang
Sichuan Agricultural University - Chengdu Campus
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Yongdong Wang
Sichuan Agricultural University - Chengdu Campus
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Zicheng Zheng
Sichuan Agricultural University - Chengdu Campus
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Tingxuan Li
Sichuan Agricultural University - Chengdu Campus

Corresponding Author:[email protected]

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Haiying Yu
Sichuan Agricultural University - Chengdu Campus
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Abstract

Cadmium (Cd) remobilization in leaves is the major source of Cd accumulation in brown rice, which is affected by whether Cd is stored in nonlabile subcellular compartments. Silicon (Si) can improve mechanical and chemical properties of cell wall in plant, however its influence in Cd immobilization in cell wall hasn’t been entirely understood. In this research, we found the isolated foliar cell wall of a rice line YaHui2816 exhibited a lower capacity for Cd chemisorption but a higher desorption amount than a contrasting line C268A, which was resulted from its fewer relative peak areas of functional groups in cell wall, such as carboxyl C=O and OH stretching. Foliar Si application increased the Cd concentration in pectin and hemicellulose 1 of foliar cell wall in YaHui2816. Combined with RNA-seq analysis, this strengthening of Cd binding in the cell wall mainly resulted from i) depressing the metal transporter OsZIP7 and ii) promoting the cell wall polysaccharide metabolism under upregulation of OsCht1 (chitinase 1) and genes participating in UDP-glucose metabolism. Overall, we revealed the mechanism by which foliar Si fertilizer improves of Cd binding onto foliar cell walls in rice, inspiring further avenues to ensure food safety in rice grains.