title: Transcriptomic, proteomic and metabolomic analysis of UV-B signaling in maize.
abstract: BACKGROUND
  Under normal solar fluence, UV-B damages macromolecules, but it also elicits physiological acclimation and developmental changes in plants. Excess UV-B decreases crop yield. Using a treatment twice solar fluence, we focus on discovering signals produced in UV-B-irradiated maize leaves that translate to systemic changes in shielded leaves and immature ears.
  
  
  RESULTS
  Using transcriptome and proteomic profiling, we tracked the kinetics of transcript and protein alterations in exposed and shielded organs over 6 h. In parallel, metabolic profiling identified candidate signaling molecules based on rapid increase in irradiated leaves and increased levels in shielded organs; pathways associated with the synthesis, sequestration, or degradation of some of these potential signal molecules were UV-B-responsive. Exposure of just the top leaf substantially alters the transcriptomes of both irradiated and shielded organs, with greater changes as additional leaves are irradiated. Some phenylpropanoid pathway genes are expressed only in irradiated leaves, reflected in accumulation of pathway sunscreen molecules. Most protein changes detected occur quickly: approximately 92% of the proteins in leaves and 73% in immature ears changed after 4 h UV-B were altered by a 1 h UV-B treatment.
  
  
  CONCLUSIONS
  There were significant transcriptome, proteomic, and metabolomic changes under all conditions studied in both shielded and irradiated organs. A dramatic decrease in transcript diversity in irradiated and shielded leaves occurs between 0 h and 1 h, demonstrating the susceptibility of plants to short term UV-B spikes as during ozone depletion. Immature maize ears are highly responsive to canopy leaf exposure to UV-B.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
authors.forename: Paula
authors.initials: P
authors.lastname: Casati
authors.forename: Mabel
authors.initials: M
authors.lastname: Campi
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Morrow
authors.forename: John F
authors.initials: JF
authors.lastname: Fernandes
authors.forename: Virginia
authors.initials: V
authors.lastname: Walbot
mesh_terms: D020869:Gene Expression Profiling; D055442:Metabolome; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D020543:Proteome / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014466:Ultraviolet Rays; D003313:Zea mays / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D020543:Proteome