High-throughput screening and structure-guided design of small molecules enable modulation of SAL-PAP stress signaling.

A small molecule inhibitor, V20, was identified that modulates SAL enzyme activity, increasing PAP levels and stress tolerance in Arabidopsis thaliana.

• Why it matters: Understanding and controlling chloroplast-to-nucleus stress signaling pathways can improve plant resilience without causing growth defects, addressing a key challenge in plant biology.
• What they did: Researchers screened 13,000 small molecules in vitro, identified V20 as a potent competitive inhibitor of AtSAL1, and used structural and biochemical analyses to define its binding features and effects.
• The result: Application of V20 increased PAP accumulation and oxidative stress tolerance in plants, demonstrating a new approach for selectively manipulating stress signaling and sulfur metabolism in plants.