Patrick Mendoza
Year: 2017
Faculty Advisor: Mike Scanlon

“Identifying Genes Involved in the Establishment of Leaf Polarity within Solanum lycopersicum”


Project Summary:

Leaves develop from shoot apical meristems (SAMs), which comprise the pool of stem cells that generate plant shoots.  Development of asymmetrically polarized leaf surfaces was a critical step in the evolution of plants that is not completely understood.  Some scientists hypothesize that there is a signal from the stem to the leaf that determines development while others contend that a signal in the leaf tip is responsible.  Thus, the genetic circumstances underlying this complex phenomenon remain unknown for many agricultural crops.  Understanding how leaves orient their tissues and organs to maximize photosynthesis and transpire efficiently has implications for future manipulation to maximize yield and is a necessary step as the world faces global warming, increased populations, and the associated increase in food needs.  

My project studies mechanisms whereby three genes affect polar leaf development in the tomato plant.  Specifically, I am analyzing mutant plants that were generated via CRISPR/Cas9 technology to determine what specific leaf phenotypes are affected.  Experimental methods used include DNA extraction and PCR amplification, sequencing to determine the nature of the genetic lesions, as well as macroscopic and microscopic analyses of the plant phenotypes throughout ontogeny.  Preliminary results indicate that these genes impact the density of leaves, leaf morphology, and epidermal cell patterning, as well as vascular tissue placement and fertility.  In conclusion, this project sheds new light on the mechanisms of leaf patterning in tomato and can potentially be used to further research in other crop species.

My Experience:

My experience as a summer REU intern has been phenomenal.  I’ve made friends and contacts that will help me through my academic career and beyond.  As a horticultural student with no experience in genetic or molecular work, being part of a large and supportive lab has given me exposure to techniques and equipment that I wouldn’t have thought possible at this stage.  Having a mentor that guided me through basic lab processes then allowed me to determine experimental paths has given me confidence and a sense of ownership that will aid in my future as a researcher.  

In addition to working on a specific project, I was exposed to many different faculty members in varying areas of plant science through seminars and in-person interactions.  Discussions with those faculty have given me insight into where I want to direct and prepare myself for graduate school.  This past summer has been invaluable in so many ways that it’s impossible to fit on this page!