Interdisciplinary PhD in Molecular Biosciences

Dr. Bruce Cahoon - Research Interests

Primary focus 1: Chloroplast Biogenesis

My lab is primarily focused on plastid biogenesis and attendant expression of plastome encoded genes. Plastids are a family of organelles in plant cells which are considered semi-autonomous due to the presence of a chromosome (plastome) yet are fully functionally integrated into numerous metabolic processes necessary for plant cell viability.

Thousands of genes, nuclear and plastome encoded, are required for plastid/chloroplast function. We choose to focus on the 120-140 genes found on the plastome itself. The plastome is a circular chromosome with genes grouped into co-transcribed (operon-like) genes which are expressed via plastid specific machinery. These co-transcribed mRNAs must be processed with endonucleases prior to translation. We are currently studying how transcript processing changes during chloroplast biogenesis.

Primary focus 2: Organelle Genomes (Plastomes & Chondriomes)

Cahoon Lab Research Interests

Plastids and mitochondria carry their own circular chromosomes. The conservation of senteny (gene order) and sequences between species and the large number of organelle chromosomes which have been completed makes a post-genomics approach to new chromosome sequencing possible. Undergraduate independent study students, genetics lab students, and some graduate students in the Cahoon lab have sequenced the complete plastome of tall fescue (Lollium arundinaceum, Genbank FJ46687 ) and the timber rattlesnake (Crotalus horridus, GenBank HM641837). The rattlesnake work is a collaboration with Vince Cobb a herpetologist in MTSU's department of biology. More sequences are on the way.

Secondary foci

Several projects undertaken in my lab have been initiated through collaborations or student interest.

  • Grass (Poaceae) identification and barcoding
  • Fescue-Neotyphodium symbiosis
  • Lipid biosynthesis gene expression in Chlamydomonas reinhardtii.