Arsenic Accumulation in two Pteris vittata Ecotypes: Insights into Transpiration, Spore As/P Ratios, and Arsenic Metabolism Gene Expression

Arsenic (As) contamination in soils poses a potential risk to human health. The arsenic-hyperaccumulator Pteris vittata has been utilized for phytoremediation of As-contaminated soils. P. vittata from different regions all accumulates As, with accumulation ability varying among ecotypes. Typically, ecotypes with greater transpiration and lower As levels in their habitat show greater As accumulation, but the underlying molecular mechanisms remain unclear. Here, we assessed the As contents, As speciation, and As metabolism-related genes in two ecotypes of P. vittata from Kunming and Hangzhou in Southwest and Southeast China. After 30 days of growth in sand media with 50 µM As, the Kunming ecotype with greater transpiration accumulated 1.5-fold more As in the fronds than Hangzhou, which was negatively correlated with its spore As contents but positively correlated with its spore P contents. Besides, the arsenite (AsIII) content in P. vittata fronds of Kunming ecotype was 1.5-fold greater than Hangzhou ecotype. The greater As and AsIII contents in the fronds of Kunming ecotype were probably due to the greater expression of As metabolism genes, including a 2.8-fold greater in P transporter PvPht1;3 (As uptake), 1.8-fold greater in arsenate reductase PvHAC2 (As reduction) and 2.9-fold greater in arsenite antiporter PvACR3;2 (As translocation), being critical genes for As accumulation by P. vittata. This is the first examination of genes related to As metabolism In different P. vittata ecotypes, providing valuable insights to select P. vittata with greater As accumulation for more efficient phytoremediation.