Genome-wide identification and characterization of phosphate transporter gene family members in tea plants (Camellia sinensis L. O. kuntze) under different selenite levels

Selenium (Se) is an essential element for human health and an important nutrient for plant growth. Selenite is the main form of Se available to plants in acidic soils. Previous studies have shown that phosphate transporters (PTHs) participate in selenite uptake in plants. Research on the PHT gene family is therefore vital for production of Se-rich products. Here, 23 CsPHT genes were identified in the tea (Camellia sinensis) genome and renamed based on homology with AtPHT genes in Arabidopsis thaliana. The CsPHT genes were divided into four subfamilies: PHT1, PHT3, PHT4, and PHO, containing nine, three, six, and five genes, respectively. Phylogenetic analysis indicated that fewer duplication events occurred in tea plants than in A. thaliana, rice, apple, and poplar. Genes in the same subfamily tended to share similar gene structures, conserved motifs, and potential functions. CsPHT genes were differentially expressed in various tissues and in roots under different Se levels, suggesting key roles in selenite uptake, translocation, and homeostasis. The results illuminate the contributions of CsPHT genes to selenite supply in tea plants, and lay a foundation for follow-up studies on their potential functions in this plant species.