Multi-omics analysis reveals the perception and defense of Betula platyphylla Suk. to Ultraviolet‑B

Ultraviolet‑B (UV-B) is not only a potential environmental stress, but also a kind of pivotal morphogenesis signal. Plants have a variety of coping mechanisms against UV-B stress. We found that long-term UV-B can change the growth phenotype of Betula platyphylla Suk. (birch), increasing the content of lignin, hemicellulose and the cell wall thickness of birch xylem. We analyzed the transcriptome, phosphoproteome, and metabolome of UV-B treated birch. The specific transcriptome response to UV-B in birch was localized to pathways such as phenylpropane and sucrose metabolism. Phosphoproteome reveals that MAPK cascade pathways and multiple CDPKs are activated by UV-B. Through metabolome analysis, we found that the metabolites of the phenylpropane pathway, sucrose pathway, variety of amino acids and lipid metabolism pathway were upregulated under UV-B treatment, and alkaloids were upregulated. We also identified an AP2/ERF transcription factor BpERF11, which can directly interact with BpMPK3 and phosphorylated in plant and in vitro. BpMPK3 mediated phosphorylation of BpERF11 increases its stability. In conclusion, our study demonstrates that UV-B activates multiple kinase signaling pathways in birch and leads to the accumulation of various secondary metabolites to scavenge reactive oxygen species. This study provides theoretical references for further investigating the molecular mechanisms underlying birch responses to UV-B regulation, laying the foundation for enhancing the adaptability of trees to environmental changes and targeted improvement of wood properties.