Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2002
Publication Date: 8/3/2002
Citation: ALBA, R., MOORE, S., PAYTON, P.R., CORDONNIER-PRATT, M., PRATT, L., GIOVANNONI, J.J. CHARACTERIZATION OF PHYTOCHROME-REGULATED TOMATO RIPENING UTILIZING FUNCTIONAL GENOMICS. AMERICAN SOCIETY OF PLANT BIOLOGISTS ANNUAL MEETING. 2002. SUPPLEMENT 369, P. 99. Interpretive Summary: SUMMARY NOT REQUIRED
Technical Abstract: We have shown that phytochromes (phy) regulate the accumulation of lycopene during tomato (Lycopersicon esculentum Mill.) ripening. Red-light (R) treatments of harvested mature-green fruit (cv. UC-82B) stimulate lycopene accumulation 2.3-fold during ripening. This R-induced lycopene accumulation is reversed by subsequent treatment with far-red light (FR), establishing that lycopene accumulation in tomatoes is regulated by fruit-localized phy. R & R/FR treatments do not influence ethylene production, fruit softening, or the accumulation of ascorbate, citrate, malate, fructose, glucose, or sucrose in pericarp, indicating that significant increases in lycopene are attainable without adverse effects on other determinants of fruit quality. These results are consistent with two conclusions: 1. fruit-localized phy regulate light-induced lycopene accumulation independently of ethylene biosynthesis, & 2. fruit-localized phy are not global regulators of ripening, but instead regulate subsets of this process. To determine the molecular nature of phy regulation of ripening parameters, cDNA microarrays & phy mutants are being utilized. A "baseline" of gene expression in pericarp during ripening has been generated for ten stages of fruit development. Expression profiles of "ripening related" genes (e.g., phytoene synthase, E8, polygalacturonase 2a, expansin) correlate well with published data. Data presented here imply that tomato maturation & ripening is the result of distinct programs of coordinated gene expression. Of the ESTs analyzed, most appear to be governed by one of these programs of coordinated gene expression. Expression profiling experiments using pericarp from phy mutants & fruit receiving specific light treatments are in progress.