1 March 2004 Genome Biology 2004, 5:R16 The electronic version of this article is the complete one and can be found online at Received: 27 October 2003 Revised: 15 December 2003 Accepted: 22 January 2004 © 2004 Casati and Walbot; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. B fluence ratesof skin cancer and has raised terrestrial levels of ultraviolet-Bfor plants | Research Open Access Rapid transcriptome responses of maize Zea mays to UV-B in irradiated and shielded tissues Paula Casati and Virginia Walbot Address Department of Biological Sciences 385 Serra Mall Stanford University Stanford CA 94305-5020 USA. Correspondence Paula Casati. E-mail pcasati@ Published I March 2004 Genome Biology 2004 5 R16 The electronic version of this article is the complete one and can be found online at http 2004 5 3 R16 Received 27 October 2003 Revised 15 December 2003 Accepted 22 January 2004 2004 Casati and Walbot licensee BioMed Central Ltd. This is an Open Access article verbatim copying and redistribution of this article are permitted in all media for any purpose provided this notice is preserved along with the article s original URL. Abstract Background Depletion of stratospheric ozone has raised terrestrial levels of ultraviolet-B radiation UV-B an environmental change linked to an increased risk of skin cancer and with potentially deleterious consequences for plants. To better understand the processes of UV-B acclimation that result in altered plant morphology and physiology we investigated gene expression in different organs of maize at several UV-B fluence rates and exposure times. Results Microarray hybridization was used to assess UV-B responses in directly exposed maize organs and organs shielded by a plastic that absorbs UV-B. After 8 hours of high UV-B the abundance of 347 transcripts was altered 285 were increased significantly in at least one organ and 80 were downregulated. More transcript changes occurred in directly exposed than in shielded organs and the levels of more transcripts were changed in adult compared to seedling tissues. The time course of transcript abundance changes indicated that the response kinetics to UV-B is very rapid as some transcript levels were altered within 1 hour of exposure. Conclusions Most of the UV-B regulated genes are organ-specific. Because shielded tissues .
