ARS | Publication request: MICROARRAY ANALYSIS OF CAROTENOID BIOSYNTHESIS GENES DURING COOL TEMPERATURE LYCOPENE PRODUCTION IN TOMATO SEPALS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 22, 2005
Publication Date: June 22, 2005
Citation: Bartley, G.E., Ishida, B.K., Zhu, T., Ono, M. 2005. Microarray Analysis of Carotenoid Biosynthesis Genes During Cool Temperature Lycopene Production in Tomato Sepals. Meeting Abstract, p. 17, 2nd Int'l Congress on Antioxidant Methods, 6/22/05, Orlando, FL.

Technical Abstract: Ripe tomato fruit are the result of numerous physiological changes controlled by hormonal and developmental signals. Ripening is characterized by tissue softening, accumulation of sugars and acids, conversion of chloroplasts to lycopene-accumulating chromoplasts, and evolution of ethylene and flavor volatiles. Of the various carotenoids found in tomato, lycopene is the most potent antioxidant in chemical assays. The consumption of tomato products containing lycopene has been shown to be associated with decreased risk of prostate cancer. Increased lycopene production in tomatoes will increase the nutritional value of tomato products. VFNT Cherry tomato sepals cultured in test tubes at 16 to 23 degrees C change their developmental program to that of ripening fruit, i.e., they evolve ethylene and accumulate lycopene, the red pigment in ripe tomato fruit. Those cultured at 28 degrees C remain green. We have used microarray analysis with a tomato oligo chip representing over 22,000 tomato genes to better elucidate carotenoid biosynthesis during cool temperature induction of lycopene synthesis. A number of carotenoid biosynthesis genes in tomato belong to gene families, at least two phytoene synthase (PSY), four putative geranylgeranyl diphosphate synthase (GGPS), possibly three isopentenyl isomerase (IPI), and three 1-deoxyxylulose-5-phosphate synthase (DXS) genes. We have determined which members of these and other carotenoid biosynthesis gene families are induced, suppressed, or constitutively expressed, during cool temperature sepal morphogenesis. Results of this analysis indicate further manipulation of more than one gene may be necessary to achieve significant increases of lycopene.