S. purpurea transcriptomics
Sarracenia purpurea Transcriptome or Gene expression
Sarracenia species (pitcher plants) are carnivorous plants which obtain a portion of their  nutrients from insects captured in the pitchers. To investigate these plants, we sequenced the  transcriptome of two species, S. psittacina and S. purpurea, using Roche 454 pyrosequencing  technology. We obtained 46,275 and 36,681 contigs by de novo assembly methods for S.  psittacina and S. purpurea, respectively, and further identified 16,163 orthologous contigs  between them. Estimation of synonymous substitution rates between orthologous and paralogous  contigs indicates the events of genome duplication and speciation within the Sarracenia genus  both occurred approximately 2 million years ago. The ratios of synonymous and non30  synonymous substitution rates indicated 491 contigs have been under positive selection (Ka/Ks  >1). Significant proportions of these contigs were involved in functions related to binding  activity. We also found that the greatest sequence similarity for both of these species was to Vitis  vinifera, which is most consistent with a non-current classification of the order Ericales as an  asterid. This study has provided new insights into pitcher plants and will contribute greatly to  future research on this genus and its distinctive ecological adaptations.