?Analysis of the maize leaf proteome after various UV-B treatments of lines differing in UV-B sensitivity?

PAULA CASATI; XIN ZHANG; AL BURLINGAME; VIRGINIA WALBOT

Aix-les-Bains, Francia

Congreso; 11th Congress of the European Society for Photobiology.; 2005

European Society for Photobiology.

We systematically surveyed responses of maize leaves to UV-B radiation using DIGE 2D gels followed by identification of selected proteins by MS/MS and Western blot analysis. Given its heightened sensitivity to UV-B the b, pl W23 flavonoid-deficient line was compared to two maize landraces from high altitudes (Cacahuacintle, and Confite Puneño) that have improved UV-B tolerance. Protein patterns in adult maize leaves (Zea mays) were documented after growth for 21 days in sunlight depleted of UV-B or growth in sunlight including an 8h UV-B supplementation during one day in the field. We found that there is a very high correlation between mRNA accumulation assessed by microarray hybridization and qRT-PCR and protein expression after UV-B irradiation in leaves of W23. Multiple isoforms were confirmed for some proteins; at least one protein, pyruvate phosphate dikinase (PPDK), is regulated post-translationally by reversible phosphorylation during UV-B exposure. Proteins differentially regulated by UV-B in W23 with higher levels under similar UV-B conditions in high altitude plants were also identified. These can be genetically fixed traits conferring UV-B tolerance and are specific adaptations to living at high altitude.