Rachel Martin and Carter Butts have sequenced the genome of the carnivorous plant Drosera capensis. This represents the first carnivorous plant genome from order Caryophyllales, and only the third genome of any carnivorous plant. Caryophylalles includes many of the best-known carnivorous plants, including the sundews (Drosera sp.), the Venus flytrap (Dionaea muscipula), and the tropical pitcher plants (Nepenthes), from which interesting and technologically useful digestive enzymes are already being discovered. The existence of pepsin-like aspartic proteases in Drosera mucilage was first hypothesized by Darwin in 1895; recent work from the Martin and Butts labs present sequences and molecular models for these proteins, which will provide a starting point for experimental investigations and technological applications. One class of proteases in D. capensis not only digests proteins but also contains an antifungal peptide insert that protects the plant from fungal infection and can potentially be adapted to fight fungal pathogens of crop plants or even humans.
This approach represents a new road map for rich annotation of genomic data, a generally applicable method for using modern computational chemistry to exploit the wealth of information provided by whole genome shotgun sequencing. Computational techniques, despite their limitations, are now powerful enough to allow potentially useful proteins to be identified directly from genomic "source code" and filtered for strong indicators of biochemical function.
Graduate students and postdocs involed in this work include Jan Bierma, Xuhong Zhang, John E. Kelly, Kyle W. Roskamp, Megha H. Unhelkar, J. Alfredo Freites, and Seemal Tahir.