A new study led by Prof. ZHANG Daoyuan of the Xinjiang Institute of Ecology and Geography of the Chinese Academy of Sciences, has uncovered the acetylation-mediated regulatory mechanisms behind desiccation tolerance in Syntrichia caninervis, a model moss widely used in desiccation tolerance research. The findings were published in Plant Physiology on March 16.

Using high-throughput acetylomics — a technique that maps chemical modifications on proteins — the researchers profiled the lysine acetylome of Syntrichia caninervis across dehydration–rehydration cycles. They identified 11,474 acetylation sites on 4,171 proteins, representing the largest such dataset ever reported for plants.

The study shows that lysine acetylation functions as a sophisticated molecular "switch" in plant cells. During dehydration, this modification fine-tunes metabolic pathways to enhance cellular stability and maintain a healthy internal chemical balance (redox homeostasis), effectively protecting the plant from damage.

Upon rehydration, however, lysine acetylation quickly redirects its regulatory role. It specifically targets key processes including glycolysis — the breakdown of sugars to generate energy — and the proteasome, the cell's degradation and repair system, to rapidly restore energy metabolism and launch cellular repair, supporting fast and strong recovery.

Notably, the team found that Syntrichia caninervis uses a unique molecular signature for its acetylation program. Whereas many other plant species favor histidine, tyrosine, and phenylalanine in related modifications, this moss shows a distinct preference for leucine.

The researchers further identified a specific protein, pyruvate kinase cPK5, and showed that acetylation at lysine 513 is critical for the protein's catalytic activity and stability. This improved function directly supports the moss's strong desiccation tolerance.

This study maps the dynamic regulatory network of lysine acetylation in an extremophilic plant, and provides new insights into how plants adapt to extreme water stress. It also offers potential strategies for breeding more drought-resistant crop varieties.