Wheat heat shock factor TaHsfA2d contributes to plant responses to phosphate deficiency

Phosphate (Pi) availability has become a major constraint limiting crop growth and production. Heat shock factors (Hsfs) play important roles in mediating plant resistance to various environmental stresses, including heat, drought and salinity. However, whether members of the Hsf family are involved in the transcriptional regulation of plant responses to Pi insufficiency has not been reported. Here, we identified that TaHsfA2d, a member of the heat shock factor family, was strongly repressed by Pi deficiency. Overexpressing TaHsfA2d-4A in Arabidopsis results in significantly enhanced sensitivity to Pi deficiency, evidenced by increased anthocyanin content, decreased proliferation and elongation of lateral roots, and reduced Pi uptake. Furthermore, RNA-seq analyses showed that TaHsfA2d-4A functions through up-regulation of a number of genes involved in stress responses and flavonoid biosynthesis. Collectively, these results provide evidence that TaHsfA2d participates in the regulation of Pi deficiency stress, and that TaHsfA2d could serve as a valuable gene for genetic modification of crop tolerance to Pi starvation.