Submitted to: Journal of Experimental Botany
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/25/2005
Publication Date: 2/10/2006
Citation: Tieman, D., Zeigler, M., Schmelz, E.A., Taylor, M., Bliss, P., Kirst, M., Klee, H. 2006. Identification of loci affecting flavor volaltile emissions in tomato fruits. Journal of Experimental Botany. 57(4):887-896. Interpretive Summary: Plant volatiles influence a myriad of biological interactions including human taste perception. Fruit volatiles that positively and negatively mediate the flavor of fresh tomatoes are derived from primary nutrient precursors including amino acids, lipids and carotenoids. A biochemical understanding of volatile production and regulation promises to enable targeted agronomic improvements in flavor and other characteristics; however, many key regulatory enzymes and elements remain unknown. Working with the University of Florida (Department of Horticultural Sciences and School of Forest Resources and Conservation), scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, FL, have discovered numerous unique chromosomal regions of the tomato genome that regulate fruit volatile emission. This knowledge will be useful both in improving fruit flavor through classical plant breeding programs and identifying specific genes controlling volatile emission, flavor, and ecological interactions.
Technical Abstract: Fresh tomato fruit flavor is the sum of interaction between sugars, acids and a set of approximately 30 volatile compounds synthesized from a diverse set of precursors, including amino acids, lipids and carotenoids. Some of these volatiles impart desirable qualities while others are negatively perceived. As a first step to identify genes responsible for synthesis of flavor-related chemicals, we have sought to identify loci that influence the chemical composition of ripe fruits. We used a genetically diverse but well defined Lycopersicon pennellii RIL population (Eshed and Zamir, 1995). Because L. pennellii is a small green-fruited species, this population exhibits great biochemical diversity and is a rich source of genes affecting both fruit development (Fridman et al. 2004) and chemical composition (Causse et al., 2004; Schauer et al. 2005). Here, we use this population to identify multiple loci affecting the composition of chemicals related to flavor. We identified 25 loci that are significantly altered in one or more of 23 different volatiles and four altered in citric acid content. Linked molecular markers should be useful for breeding programs aimed at improving fruit flavor. In the longer term, genes responsible for controlling levels of these chemicals will be important tools for understanding the complex interactions that ultimately integrate to provide the unique flavor of a tomato.