cDNA Microarray Analysis of Differential Gene Expression in Tomato Fruits Exposed to Blue, UV-A, and UV-A plus UV-B

Plants of tomato 'Micro Tom' were grown under metal-halide lamps with a UV-safe acrylic plate installed between the lights and plants. Plants with fruits at the breaker stage were transferred to a growth chamber equipped with white fluorescent lamps filtered with UV-A-absorbing (<370 nm) acrylic plates. Four hours after the start of the light period, the fruit were irradiated with one of three types of supplemental light sources: blue LED, UV-A fluorescent lamps (UV-A+UV-B), and UV-A fluorescent lamps filtered through a UV-B-safe glass plate (UV-A). Microarray hybridization was performed on all combinations of cDNAs from blue, UV-A, UV-A+UV-B, and white light groups. The gene expression profile of the UV-A group was similar to that of the control (white light), and a few genes were up-regulated slightly by blue light. In contrast, the expression of several genes was down-regulated by UV-A+UV-B. Many of these genes were categorized as those involved in transcriptional regulation and signal transduction.