Craig Richard
Craig Richard
Year: 2013
Faculty Advisor: Jeff Doyle

Selection tests and network analysis of Nod factor receptors (NFRs) in Glycine subgenus Glycine

Polyploidy is the presence of multiple sets of chromosomes in the genome of an organism. Polyploidy can result in changes in morphology, physiology and reproductive strategy, as well as changes in ecological relationships such as plant-pollinator and plant-herbivore interactions. In legumes, symbiotic relationships occur in plant root structures called nodules, which contain endosymbiotic bacteria referred to as ‘rhizobia’. Rhizobia have the ability to convert atmospheric nitrogen into nitrogen compounds accessible to the host plant. While certain studies suggest that polyploidy may have contributed to development of legume nodulation, connections between polyploidy and nodulation remain to be fully elucidated. Clarifying these connections will enhance understanding of the potential ecological impacts of both polyploidy and nodulation and will provide potential insights for agriculture. Our study examined Nod factor receptors (NFRs), which are key plant receptors involved in the signaling and perception that leads to nodulation. NFR5 sequences from four wild perennial diploid species of the Glycine subgenus Glycine polyploid complex were the focus of this study. Our goal was to establish a basis for predictions about the expected NFR sequences in Glycine subgenus Glycine allopolyploids for which the diploids in the present study are progenitors. DNA extracted from the diploid species was amplified using PCR and products were examined via gel electrophoresis, before sequencing by the Sanger method. Population genetic analyses were used to assess levels of nucleotide diversity and to test for selection. Network analysis using TCS was also conducted, providing an estimate of the gene genealogy for the sequences generated.

My Experience

As a biological engineer the research I normally conduct has a clearly defined and concrete application. Being able to see the pure research that applied research is based on has helped develop my ability to critically analyze and synthesize ideas. Interesting and innovative plant research was presented every week that always piqued my curiosity. The PGRP internship has allowed me to experience what plant research entails. It has helped me to become a more independent and more skilled researcher. The laboratory skills that I have acquired here will definitely benefit me later in my academic career. Spending this summer at Cornell University has really helped me to broaden my interests. Through this program I was able to establish relationships with people whom share the same passion for plants as I do. I look forward to future summer internships and research experiences and hope they are as amazing as this one has been.