title: Analysis of leaf proteome after UV-B irradiation in maize lines differing in sensitivity.
abstract: UV-B radiation causes diverse morphological and physiological responses in plants, but the underlying mechanisms governing these integrated responses are unknown. In this study, we systematically surveyed responses of maize leaves to UV-B radiation using DIGE 2D gels and identified selected proteins by mass spectrometry and immunodetection analysis. To identify changes in protein accumulation in response to UV-B radiation, a line (b, pl W23) deficient in flavonoid sunscreen compounds and hence similar to commercial corn was used. In addition, its proteome in natural UV-B conditions was compared with that of 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 radiation or growth in sunlight including an 8-h UV-B supplementation during 1 day in the field. We found that there is a very high correlation between previously documented mRNA accumulation assessed by microarray hybridization and quantitative real time reverse transcription-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, is regulated post-translationally by phosphorylation by UV-B exposure. Proteins differentially regulated by UV-B radiation in W23 with higher levels under similar UV-B conditions in high altitude plants were also identified. These could be genetically fixed traits conferring UV-B tolerance and offer clues to specific adaptations to living in high ambient UV-B conditions.
authors.affiliation: Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA. paulacasati@gmail.com
authors.forename: Paula
authors.initials: P
authors.lastname: Casati
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Alma L
authors.initials: AL
authors.lastname: Burlingame
authors.forename: Virginia
authors.initials: V
authors.lastname: Walbot
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010766:Phosphorylation; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D010940:Plant Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D040081:Protein Array Analysis; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D011772:Pyruvate, Orthophosphate Dikinase / Q000032:analysis; D011836:Radiation Tolerance; D014466:Ultraviolet Rays; D003313:Zea mays / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*
chemical_list: D010940:Plant Proteins; D020543:Proteome; C037396:PPDK protein, Zea mays; D011772:Pyruvate, Orthophosphate Dikinase