Abstract: Phosphorus is a macronutrient essential for plant growth and development, however, phosphate (Pi), the major form of phosphorus absorbed by plants, is quite limiting in soil. To cope with this nutritional stress, plants have evolved an array of adaptive responses, which are largely regulated by changing gene expression in response to Pi deficiency. The transcription factor, PHR1 plays a key role in regulating plant transcriptional response to Pi deficiency. Besides, most land plants can form symbiosis with arbuscular mycorrhizal (AM) fungi, through which plants can obtain Pi from soil more effectively. Recently, the research group of Ertao Wang of Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, reported that a PHR-centered gene regulatory network plays an essential role in promoting plant-AM symbiosis. Therefore, PHR not only functions in maintaining plant Pi homeostasis, but also in communicating with beneficial microorganisms in the environments, which provides another route for plants to obtain Pi from soil.

Key words: low phosphate stress, transcriptional response, PHR transcription factor, gene network, arbuscular mycorrhiza, plant-arbuscular mycorrhizal symbiosis