The expression patterns of phosphate transporter genes in relationship with PAP26 encoding a phosphatase enzyme in Arabidopsis thaliana

Phosphorus (P) is one of the most vital elements for all living organisms, which acts as a constituent of essential biomolecules and metabolic reactions. Plants to cope with phosphate (Pi) deficiency have developed different adaptive mechanisms, including induction of acid phosphatases genes, Pi transporters and release of organic acids in rhizosphere as well. Under conditions of phosphorus deficiency stress, maintaining cellular phosphorus homeostasis depends on the interactions between these components. In the present study, the relationship between gene expression pattern of three families of phosphate transporters PHT1, PHT2 and PHO1 in Arabidopsis thaliana in interaction with AtPAP26 as the dominant purple acid phosphatase among 29 identified PAPs in A. thaliana genome were studied under Pi-deficient and Pi-sufficient conditions (MS culture medium). For this purpose, three different genotypes including the wild type (Wt) plants Col-0 as the control, mutated homozygote plants with T-DNA fragment insertion (Mu26), and the homozygous overexpress plants (OE26) for AtPAP26 gene were used in all experiments. Our results showed a significant reduction in the expression level of PHT1, PHT2 and PHO1 genes, as well as the phosphatase activity in Mu26 plants compared to the Wt ones under -P condition. Under +P conditions, 58% and 42% incensement were observed in total and free phosphate content. In addition, the dry weight biomass increased 3- folds in the mutant plants compared to the wild type, respectively. On the other hand, the results showed the improvement of morphological and physiological characteristics in OE26 plants compared to Wt plants in both environmental conditions. Our result demonstrated that maintaining cellular phosphorus homeostasis in Arabidopsis plant requires the interaction of important phosphatases such as AtPAP26 with phosphate transporter in Pi stress conditions. These findings can be use in production of plants with the ability to absorb the minimum amount of phosphorus for plant growth under phosphorus stress.