Analysis of Leaf Trait and Differentially Expressed Genes of Leaf Development in Eucommia ulmoides Oliver after Ultraviolet-B (UV-B) Radiation

Background Eucommia ulmoides Oliver (EUO) has a great medicinal value in China. The using leaf model of Eucommia planting (ULMEP) is a promising approach to resolve the shortage of EUO resources. We focused on leaf responses and differentially expressed genes (DEGs) for transcriptome profiling after ultraviolet-B radiation (UV-B) in the east-north China. ResultsThe leaf traits were significantly affected after UV-B treatment, and the leaf area, leaf thickness and total leaf fresh/dry weight significantly increased (p<0.05). Anatomical results showed that cells from the leaf epidermal and palisade tissue were larger than those of control. Two transcriptome databases were assembled and integrated, the transcriptome databases comparative analysis revealed 1,826 up-regulated and 1,872 down-regulated genes. Among them, the up-regulated unigenes were mainly participated in Signal transduction mechanisms, and Cell wall/membrane biogenesis by the KOG database, and up-regulated genes were analyzed in plant hormone signal transduction and phenylpropanoid metabolic pathways by KEGG pathway. Furthermore, randomly 10 candidate unigenes expression were examined using RT-qPCR, the two libraries exhibited differential expression and were same as those obtained by sequencing. Conclusions This study was helpful to clarify the cause of leaf enlargement after UV-B treatment, the differentially expressed genes (DEGs) from plant auxin and phenylpropanoid biosynthesis signal pathways were focused on after UV-B treatment. This study provided a valuable reference for the ULMEP in the east-north China.