Phytohormonal orchestration of plant phosphate starvation responses

Abstract

Phosphorus (P) is an essential macronutrient for plant growth and development, yet its availability in soils is frequently limited due to fixation and slow diffusion. To cope with phosphate (Pi) starvation, plants have evolved sophisticated signaling networks involving multiple phytohormones that coordinate morphological, physiological, and molecular responses. This review provides a comprehensive overview of the roles and mechanisms of major phytohormones, including auxin, cytokinin, ethylene, strigolactones, abscisic acid, jasmonic acid, gibberellins, and brassinosteroids, in regulating plant responses to Pi deficiency. We also highlight recent advances in understanding how phytohormone signaling is coordinated with PHR1, the key transcription factor governing plant Pi starvation responses, including mechanisms of translational regulation, post-translational modifications, and protein-protein interactions. Finally, we propose future research directions for developing crops with improved phosphorus use efficiency through hormonal manipulation.

Keywords: PHR1; Phosphate starvation; Phosphorus use efficiency; Phytohormones; Root architecture; Signaling crosstalk.