Mark D. Lazzaro - Research

My research program in plant cell biology engages undergraduates in the lab. Many students have presented their work at the College of Charleston School of Sciences and Mathematics annual poster session. Some have presented their work at national meetings and others are co-authors on publications. Most of my work involves imaging and microscopy of live cells and organelles.

Genes and proteins that control fruit shape

Naturally occurring mutations in OVATE and other ovate family protein (OFP) genes control the shape of tomatoes and other fruits through an unclear mechanism.  Tomato flowers self-pollinate and fruit shape is determined by specific patterns of cell division and expansion in the ovary when the flowers open after pollination.  In plant cells, patterns of division and expansion are controlled by the cytoskeleton. In collaboration with Esther van der Knaap's lab at University of Georgia, we identify and characterize cytoskeletal associated proteins that co-express with OVATE to understand the mechanism of how OFPs control fruit shape.  The tools we use include bioinformatic analysis of RNA sequence data, gene cloning and fusion with fluorescent proteins, and confocal microscopy of fluorescent protein expression using the Nicotiana benthamiana leaf system.

Effect of low level laser light on mitochondria

Low level laser therapy is a therapeutic process used to promote wound repair and tissue growth in humans and other animals.  Non-thermal red laser light increases cellular metabolism through the elevation of cytochrome c oxidase (COX) activity.  One hypothesis is that the absorption of red light energy enhances the transfer of electrons through the cytochrome hemes and copper ions in COX.  The role of specific COX subunits in the response to red laser light is not known.  We use Arabidopsis thaliana knockout lines with reduced expression of specific COX subunits to understand which ones are involved in the response to red light.

Polarized growth in conifer pollen tubes

Conifer pollen tubes exhibit polarized growth but their underlying mechanisms differ from growth in flowering plant pollen tubes. These slower growing pollen tubes use microtubules and their associated motors to regulate and control elongation dependent on microfilaments and myosin. This mechanism is similar to how polarized growth occurs in mosses and ferns.

Acid secreting trichomes

Many plants are covered with trichomes, multicellular hairs that secrete many different compounds. Chickpea trichomes secrete hydrochloric acid and other compounds. This acid can be quite strong, with a pH of 0.5 in collected secretions! The mechanism controlling this secretion is not known. These trichomes also contain a system of tubular vacuoles which pass between cells through a plasmodesmata like system.