State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, the Research Institute of Subtropical Forestry Chinese Academy of Forestry, Hangzhou, Zhejiang 311400, PR China; Zhejiang Xiaoshan Institute of Cotton & Bast Fiber Crops, Zhejiang Institute of Landscape Plants and Flowers, Zhejiang Academy of Agricultural Sciences, Hangzhou 311251, China.
Key Laboratory of Three Gorges Regional Plant Genetic & Germplasm Enhancement (CTGU)/ Biotechnology Research Center, China Three Gorges University, Yichang 443002, Hubei, PR China.
J Hazard Mater. 2024 Jul 5;472:134517. doi: 10.1016/j.jhazmat.2024.134517. Epub 2024 May 4.
Cadmium (Cd) is a heavy metal pollutant mainly originating from the discharge of industrial sewage, irrigation with contaminated water, and the use of fertilizers. The phytoremediation of Cd polluted soil depends on the identification of the associated genes in hyperaccumulators. Here, a novel Cd tolerance gene (SpCTP3) was identified in hyperaccumulator Sedum plumbizincicola. The results of Cd binding and thermodynamic analyses, revealed the CXXC motif in SpCTP3 functions is a Cd binding site. A mutated CXXC motif decreased binding to Cd by 59.93%. The subcellular localization analysis suggested that SpCTP3 is primarily a cytoplasmic protein. Additionally, the SpCTP3-overexpressing (OE) plants were more tolerant to Cd and accumulated more Cd than wild-type Sedum alfredii (NHE-WT). The Cd concentrations in the cytoplasm of root and leaf cells were significantly higher (53.75% and 71.87%, respectively) in SpCTP3-OE plants than in NHE-WT. Furthermore, malic acid levels increased and decreased in SpCTP3-OE and SpCTP3-RNAi plants, respectively. Moreover, SpCTP3 interacted with malate dehydrogenase 1 (MDH1). Thus, SpCTP3 helps regulate the subcellular distribution of Cd and increases Cd accumulation when it is overexpressed in plants, ultimately Cd tolerance through its interaction with SpMDH1. This study provides new insights relevant to improving the Cd uptake by Sedum plumbizincicola.
镉（Cd）是一种重金属污染物，主要来源于工业污水排放、受污染水灌溉和化肥使用。镉污染土壤的植物修复依赖于超富集植物中相关基因的鉴定。在这里，我们在超富集植物景天属中鉴定了一个新的镉耐受基因（SpCTP3）。镉结合和热力学分析的结果表明，SpCTP3 中的CXXC 基序是一个镉结合位点。突变的 CXXC 基序使 SpCTP3 对 Cd 的结合能力降低了 59.93%。亚细胞定位分析表明，SpCTP3 主要是一种细胞质蛋白。此外，与野生型Sedum alfredii（NHE-WT）相比，SpCTP3 过表达（OE）植株对 Cd 的耐受性更强，积累的 Cd 更多。SpCTP3-OE 植株的根和叶细胞细胞质中 Cd 浓度分别显著升高（分别为 53.75%和 71.87%）。此外，在 SpCTP3-OE 和 SpCTP3-RNAi 植株中，苹果酸水平分别增加和降低。此外，SpCTP3 与苹果酸脱氢酶 1（MDH1）相互作用。因此，SpCTP3 有助于调节 Cd 的亚细胞分布，并在植物中超表达时增加 Cd 积累，最终通过与 SpMDH1 的相互作用提高 Cd 耐受性。本研究为提高景天属对 Cd 的吸收提供了新的见解。
