Recently, the Innovation Team of Soil-Plant Interactions of the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) found that the process of phosphorus accumulation of the CrPHT3 gene-mediated significantly influences the arsenic tolerance of Chlamydomonas reinhardtii. This work provides a new perspective and in-depth understanding on the regulatory role of mitochondrial phosphate transport proteins in the arsenic metabolism in plant, and supplies important scientific references for protecting aquatic environments, mitigating plant arsenic toxicity, and developing new phytoremediation technologies. This finding was published by the title "Phosphorous accumulation associated with mitochondrial PHT3-mediated enhanced arsenate tolerance in Chlamydomonas reinhardtii" in the Journal of Hazardous Materials.

Arsenic are widely distributed in nature, and easily enter the environment through natural migration and transformation processes as well as human activities, thus impacting organisms and even human health. In response to environmentally friendly remediation policies, natural water environments are more inclined towards plant and ecological restoration. Algae, as typical floating aquatic plants, play a role in regulating the biogeochemical cycle of arsenic elements in nature and possess natural advantages in improving the water quality of arsenic-polluted waters. Therefore, algae serve as excellent materials for efficient and cost-effective plant remediation, playing an important regulatory role in arsenic-polluted water restoration.

Researchers focused on Chlamydomonas reinhardtii and the Crpht3 mutant, and performed an in-depth analysis on arsenic tolerance of the mitochondrial phosphate transport protein PHT3 gene-mediated. The study revealed that the wild-type C30 strain of Chlamydomonas reinhardtii and the Crpht3 mutant had no phenotypic difference under phosphate supply. However, under 500 μmol L-1 pentavalent arsenic stress, an adequate supply of phosphate significantly increased the absorption of polyphosphates and intracellular phosphates in the Crpht3 mutant, enhancing arsenate tolerance of the Crpht3 mutant. Under arsenate stress, the Crpht3 mutant significantly upregulated the PHT3 gene, leading to the accumulation of more phosphates in the cytoplasm, triggering the up-regulation of different genes, thus affecting the metabolism processes such as glutathione redox reactions, antioxidant activity, and cellular detoxification capacity. In contrast, the wild-type C30 strain of Chlamydomonas reinhardtii accumulated lower phosphate and exhibited weaker arsenate tolerance, indicating that the CrPHT3 gene could influence the phosphate accumulation profile, thereby alleviating arsenate toxicity in algal. This achievement provides a new approach and perspective for utilizing specific gene-modified plants in low-cost, environmentally friendly strategies for phytoremediation in the aquatic environment with heavy metal pollution.

Dr. Tao Leyuan from the Institute of Agricultural Resources and Regional Planning at the Chinese Academy of Agricultural Sciences and Associate Professor Wang Long from Yangzhou University are the co-first authors of the paper, with Professor Zhang Qianru and Professor Cheng Xianguo as the corresponding authors. The research was jointly supported by the National Key Laboratory for Efficient Utilization of Dryland Cropland in Northern China, the National Key Research and Development Program, and the Major Tasks of the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences.

[Citation]:

Tao, L.Y., Wang, L., Liu, L.H., Cheng X.G.*, Zhang Q.R.* 2024. Phosphorous accumulation associated with mitochondrial PHT3-mediated enhanced arsenate tolerance in Chlamydomonas reinhardtii. Journal of Hazardous Materials. 478: 135460

Original Article Link: https://doi.org/10.1016/j.jhazmat.2024.135460