Transcriptome profiling of the UV-B stress response in the desert shrub Lycium ruthenicum

Abstract

Ultraviolet-B (UV-B) is a natural component of the solar radiation. Due to its high energy, low dosages of UV-B can bring huge potential damage effect to organisms. Despite much research that has analyzed the gene expression changes of plants that under UV-B radiation, the transcriptome response of Lycium ruthenicum under the UV-B induction is still unavailable. The aim of our study was to identify UV-B responsive genes and gain an insight into the underlying genetic basis of the pathobiology of UV-B related damage. We collected leaf samples from L. ruthenicum with and without UV-B exposure, and then performed a transcriptome profiling to comprehensively investigate their expression signatures. By employing the high throughput RNA-sequencing analysis of samples with and without UV-B exposure, we identified 1,913 up-regulated and 536 down-regulated genes at least by twofold changes. The activity of antioxidant enzyme related genes, including the superoxide dismutase, was decreased, genes related to the synthesis of secondary metabolites and defense responses, such as cinnamyl alcohol dehydrogenase, chalcone-flavanone isomerase and dihydroflavonol reductase were also downregulated. The expression patterns of 14 randomly selected genes resulted from quantitative real-time PCR were basically consistent with their transcript abundance changes identified by RNA-sequencing. We found that several biological pathways related to biotic and abiotic stresses, including cell defense, photosynthesis processes, energy metabolism, were involved in the process of UV-B stress response. A genome-wide screening of gene deregulation under UV-B induction would provide an insight into the understanding of the molecular bases and pathogenesis of UV-B responses.