Pyramiding for Fruit Nutritional Quality: Elucidating the genetic basis of folate accumulation utilizing tomato F2 populations
Folate (Vitamin B9), the collective name for tetrahydrofolate and its derivatives, are vital compounds required for the metabolism of nearly all organisms. Plants and many microorganisms synthesize folates de novo, however, humans lack this ability and require a dietary supplement, mostly from plant foods. Deficiencies in folate are associated with congenital abnormalities like neural tube defects, as well anemia, cardiovascular diseases, certain cancers and dementia. Folate deficiency remains a severe challenge worldwide, especially in developing countries. Due to the risks of folate deficiencies, governments and health organizations worldwide have recommended folate supplementation, leading to mandates on fortification of foods with synthetic folic acid in western countries. It is important to diversify dietary sources of folate, and biofortification has been proposed as another means of increasing intake of natural folates. The tomato fruit is a good model because of available breeding populations, such as the Solanum pennellii introgression lines (ILs). Each of the ILs contains a genetically mapped, single introgression from the green-fruited, wild species S. pennellii in the background of S. lycopersicum cv. M82. In this study, the objective was to identify quantitative trait loci associated with elevated fruit folate levels. Previous work analyzing genetic variation of folate levels in the ILs identified lines significantly higher and lower in folate compared to M82. Lines were also selected based on differences in expression of folate biosynthetic genes. The resulting data was used to generate crosses between selected ILs in order to pyramid (i.e., increase) folate levels. The F2 progeny of these crosses were screened for genetic markers bordering the introgressions and scored. A microbiological assay was then used to measure folate levels; this revealed that folate content is a complex nutritional trait. Further genotyping and gene expression analysis in these lines will be undertaken to elucidate the genetic basis of folate accumulation.
I really enjoyed working at BTI this summer. Through the program, I was able to learn in depth about the process plant genome research. Not only did I learn widely applicable skills in the lab, but I was also able to learn about the process of applying for funding, presenting my research, and other skills crucial for a career in plant science research. I especially enjoyed the graduate school panel, where I got an in-depth view of Cornell’s graduate programs. The panelists were passionate about their research and highlighted the revolutionary research at Cornell. Activities like the seminar series were captivating and showed me the breadth of research in the plant sciences. After each seminar, I appreciated how we were able to get lunch and discuss their research with each lecturer. Working in the Giovannoni lab, every member was cordial and a pleasure to work with each day. I am especially grateful for my mentor Betsy Ampofo who gave her insightful guidance throughout the summer. Through my mentor, I was able to learn invaluable lessons in experimental design and other skills crucial in plant genome research. Leaving the BTI PGR program, I look forward to a career in scientific research.