A PHR-dependent Reciprocal Antagonistic Interplay Between UV Response and P-deficiency Adaptation in Plants

Plants are often simultaneously stressed by both UV radiation and phosphorus (P) deficiency in agricultural ecosystems. Coordinated responses and adaptations to these stressors are critical for plant growth, development, and survival. However, the underlying molecular response and adaptation mechanisms in plants are not fully understood. Here, we show that plants use a reciprocal antagonistic strategy in response to UV radiation and P deficiency. UV radiation inhibits P-starvation response processes and disrupts phosphate (Pi) homeostasis by suppressing the function of PHOSPHATE STARVATION RESPONSE PROTEINS (PHRs), the Pi central regulators. Conversely, P availability modulates plant UV tolerance and the expression of UV radiation response genes in a PHR-dependent manner. Therefore, reducing the P supply or increasing PHR activities can improve tolerance to UV stress in rice. Moreover, this antagonistic interaction is conserved across various plant species. Our meta-analysis showed that the increase in global UV radiation over the last 40 years may have reduced crop P-utilization efficiency worldwide. Our findings provide insights for optimizing P fertilizer management and breeding smart crops that are resilient to fluctuations in UV radiation and soil P levels.