<i>SpHsfA4c</i> from <i>Sedum plumbizincicola</i> Enhances Cd Tolerance by the AsA–GSH Pathway in Transgenic <i>Populus × canescens</i>
Miao Yu,
Zhengquan He,
Shaocui Li,
Zhuchou Lu,
Juanjuan Chen,
Tongbao Qu,
Jing Xu,
Wenmin Qiu,
Xiaojiao Han,
Renying Zhuo
Affiliations
Miao Yu
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
Zhengquan He
Key Laboratory of Three Gorges Regional Plant Genetic & Germplasm Enhancement (CTGU)/Biotechnology Research Center, China Three Gorges University, Yichang 443002, China
Shaocui Li
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
Zhuchou Lu
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
Juanjuan Chen
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
Tongbao Qu
College of Forestry and Grassland, Jilin Agricultural University, Changchun 130118, China
Jing Xu
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
Wenmin Qiu
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
Xiaojiao Han
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
Renying Zhuo
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding of Zhejiang Province, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
The ascorbate (AsA)–glutathione (GSH) metabolism pathway is an important antioxidant system in cadmium (Cd) detoxification; the AsA–GSHpathway is generally regulated by a specific set of functional genes. However, transcription factors involved in AsA–GSH pathway have yet to be identified. Herein, we transformed a heat shock transcription factor SpHsfA4c from Sedum plumbizincicola into Populus. × canescens. Under 100 μM CdCl2 stress for 30 d, the leaf chlorosis of wild-type poplars (WT) is more serious than that in transgenic poplars. The root biomass, shoot biomass and tolerance index (TIs) of transgenic poplars were higher than those in WT. In addition, transgenic poplars have higher Cd2+ uptake and Cd content. Compared with WT, the contents of hydrogen peroxide (H2O2) and superoxide anion (O2•−) in transgenic poplars were significantly reduced in leaves under Cd treatment. The expression levels of five enzymes (ascorbate peroxidase (APX), catalases (CAT), superoxide dismutase (SOD), peroxidase (POD) and glutathione S-transferase (GST)) were higher in transgenic poplars than those in WT. Transgenic poplars contained higher concentrations of intermediate metabolites, including GSH, AsA and phytochelatins (PCs), and a higher GSH/GSSG ratio in the AsA–GSH metabolism pathway. In Fourier transform infrared (FTIR) spectra, the characteristic peaks indicated that the contents of cysteine, GSH and AsA in transgenic poplars were exceeded compared to those in WT. These results suggested that SpHsfA4c can activate the AsA–GSH metabolism pathway to reduce Cd-associated oxidative stress. Therefore, overexpressing SpHsfA4c in P. × canescens can give rise to a superior Cd tolerance. Our results provide a theoretical significance for breeding potential new germplasm resources with high biomass and high Cd tolerance for remediation of soil heavy metal pollution.
