Michael Dzakovich, of the Department of Horticulture and Crop Science, will be speaking in 102 Rightmire Hall on July 12th at 12:30 PM.
Title: From Bitter to Better: Exploring Variation in Tomato Glycoalkaloids
Abstract: Tomatoes (Solanum lycopersicum) are an economically and nutritionally important crop that produce many phytochemicals including tomato steroidal glycoalkaloids (tSGAs). Tomatoes uniquely produce tSGAs which provide protection against biotic stress due to their fungicidal and insecticidal properties. Pre-clinical studies have suggested that tSGAs strongly contributed to health benefits observed in mice that consumed tomato-rich diets. However, little is known about the chemical diversity, structure, and concentration of most tomato tSGAs. We hypothesized that genetic variation would influence the type and concentration of tomato fruit tSGAs. To test this hypothesis, we developed a panel of 108 genetically diverse tomato accessions including 25 accessions of Solanum pimpinellifolium and 32 accessions of Solanum lycopersicum var. cerasiforme. In addition, we included commercial processing and fresh market germplasm. Our diversity panel was grown in three environments and red ripe fruits were characterized for 22 tSGAs using an ultra-high performance liquid chromatography tandem mass spectrometry method. We found that tSGA concentrations and profiles varied considerably in tomatoes based on their genetic background and environment. Data from populations constructed to determine the inheritance of α-tomatine, a prominent tSGA, indicate that high levels are recessive. This observation suggests loss of function; either loss of degradation, modification, or sequestration. Preliminary mapping experiments are underway to describe the genetic architecture of α-tomatine concentration in ripe fruits. Our data indicate that there is substantial natural variation present in tomato tSGAs that may be exploited to develop new germplasm potentially with improved biotic stress resistance and human health benefits.