Insights into plant phosphate sensing and signaling

- Pi stress restricts primary root growth through dual regulatory pathways.
- Vacuolar transporters regulate cytosolic Pi homeostasis.
- InsP interacts with SPX domain to regulate Pi transport and/or signal transduction.
- Phloem delivers Pi signaling RNAs to specific sinks for downstream regulation.
- Phosphate starvation-response (PSR) attenuates plant defenses to allow symbiosis with beneficial microbes.

Phosphorus (P) is a macronutrient essential for plant growth, therefore, soil P level is critical to crop yield potential in agriculture. As Pi levels limit crop yield under many soil conditions, it is crucial to understand the mechanisms by which plants adapt to low-phosphate (Pi) soil conditions and interact with their soil microbiome to improve crop P use efficiency, in order to ensure global food security. Recent advances have been made towards achieving this goal through advancing our understanding of the plant's response to limiting Pi conditions to maintain P homeostasis. In this review, we assess advances made in local and systemic Pi sensing and signaling, and in the molecular events for Pi absorption, redistribution and plant-symbiont interactions. These findings offer important avenues for bio-engineering of agricultural crops with traits for enhanced Pi acquisition and utilization.

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