Integrated analysis of transcriptome and proteome provides novel insights into the response mechanisms of maca (Lepidium meyenii Walp.) to UV-B radiation

UV-B radiation is a significant environmental factor that affects a wide range of biological processes in plants. Maca (Lepidium meyenii Walp.), a critical herbaceous plant native to high altitudes, shows strong adaptation to environmental stimuli including UV-B radiation. Despite the importance of maca for studying high-altitude adaptation, comprehensive transcriptomic and proteomic data on the response of maca to UV-B are lacking. This study used integrated comparative transcriptomics and proteomics to examine the gene and protein expression in maca leaves exposed to UV-B radiation for 0, 12, 24, and 36 h. As a result, 7255 significant differentially expressed genes and 257 differentially expressed proteins were identified following UV-B exposure. Bioinformatics revealed that UV-B radiation induced complex changes in the transcriptome and proteome of maca, affecting energy, carbohydrate, nucleotide, and glycan metabolism. Enrichment and protein-protein interaction network analyses highlighted the "glutathione metabolism" pathway as significantly upregulated upon UV-B radiation. Quantitative PCR of eight genes associated with this pathway revealed that seven exhibited significant transcriptional upregulation, highlighting the critical role of this pathway in maca response to UV-B radiation. Glutathione content measurement and inhibition assays demonstrated that disruption of the "glutathione metabolism" pathway led to a significant reduction in UV-B-induced total glutathione, reduced glutathione, and oxidized glutathione levels. This further supports the conclusion that the "glutathione metabolism" pathway plays a crucial role in maca's response to UV-B radiation. The transcriptomic and proteomic data presented here provide valuable insights into the functional aspects and molecular response mechanisms of maca plants to UV-B radiation.