Transcriptome analysis of Clematis lanuginosa: Novel features of the molecular events occurring under heat-shock stress

The weak heat tolerance of Clematis ornamental varieties negatively affects their ornamental qualities in the summer. To elucidate heat resistance mechanisms, Clematis lanuginosa, which is an important original parent of the Clematis large-flowered group of ornamental varieties, was selected for use in this study. Here, six libraries, including three biological replicates each of control and heat-shock stress samples, were determined using RNA-sequencing technology. In total, 62,050 unigenes were obtained, and 6,439 unigenes exceeded 1 kb in length. A total of 42,377 unigenes were annotated using six databases. Between the two treatments, 2,165 differentially expressed genes were identified, with 1,565 being up-regulated and 600 down-regulated. In addition, 51 heat-shock protein-encoding genes were identified, among which the small heat-shock proteins accounted for 68.63%. In total, two heat-shock factors and 12 ribosomal proteins were significantly up-regulated under heat-stress conditions. The differential expressions of ethylene-responsive transcription factor, chalcone synthase, cysteine-rich receptor-like kinase and aspartic protease unigenes in guard cells were induced by heat-shock. The data obtained will assist the elucidation of the molecular events underlying heat-stress responses in C. lanuginosa.