Dehydration-Responsive Element-Binding Factor 2C Activates PHOSPHATE TRANSPORTER1;9 in Arabidopsis thaliana in Response to Phosphate Starvation

Lack of the mineral nutrient phosphate (Pi) greatly limits plant growth and development. This study addressed the role of dehydration-responsive element-binding factor 2 C (DREB2C) in regulating Pi starvation in Arabidopsis thaliana. Both levels of DREB2C transcript and DREB2C promoter-driven beta-glucuronidase activity increased under Pi-starvation conditions. Plants overexpressing DREB2C maintained their root architecture. DREB2C overexpression was associated with increased expression of PHOSPHATE TRANSPORTER1;9 (AtPHT1;9), which is responsible for phosphate translocation in Arabidopsis roots and shoots. DREB2C directly bound to the AtPHT1;9 promoter and acted as a transcriptional activator of AtPHT1;9 during Pi starvation. Moreover, expression of AtPHT1;9 and total phosphate capacity increased in plants overexpressing DREB2C. These findings demonstrated that, by regulating AtPHT1;9 expression, DREB2C played a crucial role in maintaining Pi homeostasis in plants experiencing environmental Pi starvation.