Fitzek-Campbell
Dr. Elisabeth Fitzek-Campbell
Current Research Projects
- Land plant terrestrialization
The verification of charophyte green algae (CGAs) as closest cousin to land plants sparked the new interest to investigate the transition from water to land at the molecular scale. Briefly, CGAs consists of six lineages and are divided into 2 clades: basal CGA or KCM (Mesostimatophyceae, Chlorokybophyceae, Klebsormidiophyceae) and the advance CGA or ZCC. Previous RNA-Seq and genome analysis of Spirogyra sp. and K. nitens have confirmed the presence of proteins involved in hormone biosynthesis and response among others. Plant hormones are important for sensing environmental changes and adequately responding to it. Furthermore, these are relevant for plant development. Here we are focusing on two plant hormones, namely abscisic acid (ABA) and cytokinin (CK). These are crucial for stress signaling and plant development.
Furthermore, cross-talk between both signaling pathways mediate critical decisions between stress response and growth. We hypothesize that similar cross-talk existed already in the progenitor of land plants. Since in land plants cross-talk between hormones allows thriving and fast response to a changing environment. We are investigating different species and strains within the ZCC clade and determine their response towards environmental stresses, such as osmotic stress, in a time-series manner. This study will contribute to the understanding if cross-talk already excited in CGAs or if it occurred after plants established themselves on land.
- Polysaccharide utilization in marine species Vibrio
Alginate is one of the most abundant carbon sources in the marine environment and found for example in seaweed. It has a wide application in food, pharmaceutical industry as well as promising aspects in biofuel. In bacterioides, the degradation pathway of polysaccharide utilization loci (PULs) and alginate utilization loci (AUL) is carried out by a well characterized transporter duo SusC-SucD. However, in proteobacteria the SusC-SusD transporters are absent. This suggests that AULs in marine proteobacteria contain a different uptake mechanism.
In this project we investigated the utilization of alginate in a newly isolated scallop gut bacterium. Genome sequencing of the newly isolated bacterium predicted its placement within the Vibrio genus and was named Vibrio splendidus OU02. An in-house script was developed to find potential regions of alginate utilization loci (AUL). These are composed of carbohydrate active enzymes, transporter(s) and transcription factors Genome assembly (RAST), annotation (BLAST, HMMER) and comparative genome analyses across the Vibrio genus (Mauve), revealed a large AUL gene cluster with a multi-domain Aly gene. Furthermore, RNA-Seq analysis of glucose and alginate treated V. splendidus OU02 species confirmed the up-regulation of AlyB and KdgM (Fig 1). Future experiments will entail the protein characterization of AlyB.
