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

PAULA CASATI; XIN ZHANG; ALMA L. BURLINGAME; VIRGINIA WALBOT

Pinamar

Congreso; XLI Reunión Annual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2005

We systematically surveyed responses of maize leaves to UV-B radiation using DIGE 2D gels followed by identification of proteins by MS/MS. Given its heightened sensitivity to UV-B the b, pl W23 flavonoid-deficient line was compared to two landraces from high altitudes (Cacahuacintle, and Confite Puneño) that have improved UV-B tolerance.  Protein patterns in adult maize leaves 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 by 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.