Poster

         Education and Outreach

Student Exploration of the Plastid Genome

Presenting Author
Sue Harley
Description
One of the fascinating aspects of plant biology that students are often unfamiliar with is their three genomes: nuclear, mitochondrial, and plastid.  We put together a laboratory experience with a follow up phylogenetics exercise to provide students the opportunity to explore the plastid genome, using either chloroplasts or the usually less familiar chromoplasts. After an overview of the structure of the plastid genome, types of plastids, and plastid heredity, students isolate chloroplasts or chromoplasts from leaves, flowers, or fruits using a high salt method (Shi et al., 2012). We have found that this method works well for both chloroplasts and chromoplasts from a variety of flowering plants. With the high salt method, highly pure plastids suitable for subsequent DNA extraction can be obtained using benchtop centrifuges without the need of sucrose, Percoll, or Ficoll gradients. Students use one lab period to isolate plastids and a second period to extract DNA using a plant-specific DNA prep kit. They then check the quality of their DNA preps by A260/A280 ratio and electrophoresis.  As a follow up exploration, students are introduced to using the plastid genome in phylogenetics. They can look up the plastid DNA sequence for their plant or a related one and select restriction enzymes for further study of their chosen plastid’s DNA.