Venus Flytrap Secrets Revealed

To identify and quantify the proteins present in the digestive fluid, an approach combining transcriptomics and proteomics was applied (Figure 2). The researchers initially carried out deep sequencing of cDNA derived from Venus flytrap leaves that were stimulated by different methods, including feeding with ants and beetles. For the proteomics analyses, protocols were developed that avoided contamination of digestive fluid with prey proteins. Using these artificial stimulation methods, the researchers collected digestive fluid and analysed it by mass spectrometry.

The data obtained were searched against the transcriptomes and the proteins present in the digestive fluid were identified, quantified, and functionally annotated using this approach. The data showed that the protein composition is very different from that in animal digestive juices. In vertebrates and in the carnivorous plant Nepenthes, the proteolytic enzymes are mostly aspartic proteases. In the Venus flytrap, however, cysteine proteases were the most abundant class, followed by a serine carboxypeptidase and aspartic proteases. As expected, chitinases that probably facilitate degradation of the exoskeleton of trapped insects were also identified. The majority of the most abundant proteins in the digestive fluid were homologous with proteins involved in the defense against pathogens in other plants. This suggests a shift from defense-related processes to digestion-related processes among the carnivorous plants.

The majority of the most abundant proteins in the digestive fluid were homologous with proteins involved in the defense against pathogens in other plants. It suggests a shift from defense-related processes to digestion-related processes among the carnivorous plants.
The strategic research alliance NOVENIA

Dr. Jan J. Enghild’s group is continuing its work on the Venus flytrap plant and recombinant versions of the major enzymes to gain a better understanding of their biochemical characteristics and the digestion mechanism at the molecular level. In addition, the biochemical analyses may reveal properties that could be exploited commercially. This is of interest for the industrial partners in the research alliance ‘Novel enzymes of industrial relevance: specialized proteolytic enzymes for release of new bioactive peptides (NOVENIA)’, see www.novenia.dk, supported by the Danish Council for Strategic Research. In NOVENIA, different digestive systems and marine microbial communities are being analysed to identify proteolytic enzymes of industrial relevance.

The findings have just been published in Molecular and Cellular Proteomics (http://www.mcponline.org).

The project was carried out in collaboration with colleagues at the University of Southern Denmark, the Max Planck Institute of Molecular Plant Physiology (Potsdam), the Heinrich Heine University Düsseldorf, and the University of Würzburg.

Contacts and sources: