David Martinez
David Martinez
Year: 2013
Faculty Advisor: Jim Giovannoni

Development of nearly isogenic lines of tomato for the gene conferring the green shoulder phenotype

The tomato uniform ripening (u) mutation confers a light green fruit phenotype as compared the wild type (U) green shoulder and is widely used in breeding for tomato varieties producing evenly ripened fruit. U encodes a GLK transcription factor influencing chlorophyll accumulation and distribution in developing fruit. Tomato GLK influences fruit chloroplast development and fruit quality and manipulating GLK expression is a means to enhance fruit quality and nutritional value. Most commercial tomato varieties have the u mutation and hence non-functional GLK protein. One approach to manipulate GLK expression is to bring back the normal green shoulder phenotype to elite cultivars using traditional breeding techniques. The introgression line 10-1 of Solanum pennellii in the cultivated tomato M82 has the green shoulder phenotype but also contains a large segment of chromosome 10 from the wild species that may include genes that could modify characters other than the green shoulder phenotype targeted here. I screened a large segregating population derived from this introgression line to identify recombination events near the U locus and successfully identified several plants with smaller introgressed fragment sizes. Homozygous progeny from these plants will be compared with the M82 line for sugar and carotenoids to test the effect of the green shoulder phenotype absent changes that might result from additional linked wild species alleles.

My Experience

My overall experience here in the Giovannoni lab was great. The environment and lab setting has giving me the confidence to continue research. Along with learning new techniques I feel that I will benefit from and can bring along with me in any research I may conduct in the future. Although I’ve learned plenty of different things in the lab, I feel that one thing that I’ve learned is more patience. Working one-on-one with my mentor and other faculty members has giving me the opportunity to troubleshoot experiments. My mentor has also giving me the chance to work independently and stressed the importance of being precise in scientific tests. This being my first internship, I’ve learned a new level of respect and the hard work that goes into the production of conclusive data in science.