Multifunctional Roles of Zinc in Cadmium Transport in Soil–Rice Systems: Novel Insights from Stable Isotope Fractionation and Gene Expression

作者：Songxiong Zhong, Xiaomin Li, Liping Fang, Jianghao Bai, Ruichuan Gao, Yao-Hui Huang, Yingmei Huang, Yuhui Liu, Chuanping Liu, Haoming Yin, Tongxu Liu, Fang Huang, Fangbai Li · 发表于：Environmental Science & Technology · 年份：2024 · DOI：10.1021/acs.est.4c01851 · 被引用次数：30 · 研究领域：Heavy metals in environment、Plant Micronutrient Interactions and Effects、Aluminum toxicity and tolerance in plants and animals

The effect of Zn on Cd accumulation in rice varies under flooding and drainage conditions, and the underlying mechanism during uptake and transport from the soil to grains remains unclear. Isotope fractionation and gene expression were investigated using pot experiments under distinct water regimes and with Zn addition to gain a deeper understanding of the molecular effects of Zn on Cd uptake and transport in rice. The higher OsHMA2 expression but constitutively lower expression of zinc-regulated, iron-regulated transporter-like protein ( ZIP ) family genes in roots under the drainage regime than the flooding regime caused the enrichment of nonheavy Zn isotopes in the shoots relative to roots but minimally affected Cd isotopic fractionation. Drainage regime seem to exert a striking effect on the root-to-shoot translocation of Zn rather than Cd, and increased Zn transport via OsHMA2. The changes in expression patterns in response to Zn addition were similar to those observed upon switching from the flooding to drainage regime, except for OsNRAMP1 and OsNRAMP5 . However, soil solution-to-rice plants and root-to-shoot fractionation toward light Zn isotopes with Zn addition (Δ 66 Zn rice plant-soil solution = −0.49 to −0.40‰, Δ 66 Zn shoot-root = −0.36 to −0.27‰) indicated that Zn transport occurred via nonspecific uptake pathways and OsHMA2, respectively. Accordingly, the less pronounced and minimally varied Cd isotope fractionation suggested that OsNRAMP5 and OsHMA2 are crucial...