Transcriptional Regulation of Pi Starvation Responses by WRKY75.

Adaptive responses during phosphate (Pi) starvation are regulated by complex molecular mechanisms in plants. Transcription factors are believed to be the key determinants of Pi starvation responses. We have recently identified the plant-specific WRKY75 transcription factor as an important component of the Pi stress responses. WRKY75 is a positive regulator of several phosphate starvation induced (PSI) genes including phosphatases, Mt4/TPS1-like genes and high affinity Pi transporters. It also acts as a negative regulator of some components of root development, independent of Pi stress response. WRKY75 has considerable effect on anthocyanin accumulation, Pi uptake and Pi content in the plant. Here we present a hypothetical model of transcriptional regulation during phosphate starvation induced processes in plants which help in the maintenance of Pi homeostasis.