Comparative proteomics analysis of the effect of combined red and blue lights on sugarcane somatic embryogenesis

Sugarcane is a renewable energy source that provides an alternative to fossil fuels and somatic embryogenesis can improve plant breeding for this purpose. Sugarcane somatic embryo development involves several unknown biochemical and molecular processes, and shotgun proteomics analysis may be helpful for the identification of somatic embryo-related proteins. The aims of this study were to evaluate the influence of combinations of red and blue wavelengths from LED lamps on the maturation of somatic embryos of sugarcane cv. SP80-3280 and to identify proteins that might be associated with the morphogenetic response. Embryogenic callus were subjected to maturation treatments with various combinations of red and blue wavelengths, and a fluorescent lamp was used as a control. The W_mB_dR_fR (450/530/660/735 nm) treatment for 28 days yielded 58 somatic embryos per callus, whereas the control yielded 23 somatic embryos per callus. Samples from the control and W_mB_dR_fR treatments were subjected to shotgun proteomic analysis and the proteomics data were processed with Progenesis QI software against the SUCEST project database. The quantitative shotgun proteomics analysis identified 1171 proteins common to the fluorescent and W_mB_dR_fR treatments, and of these 39 and 38 proteins were up-regulated and down-regulated, respectively, in the W_mB_dR_fR compared with the fluorescent treatment. The W_mB_dR_fR treatment induced a higher abundance of methyltransferases and clathrin heavy chain 1, which are related to differentiation and dedifferentiation processes and might be candidate markers for sugarcane somatic embryogenesis. Overall, our data indicate that LEDs can be advantageous substitutes for fluorescent lamps and that a combination of red and blue lights can enhance somatic embryo maturation and conversion in sugarcane.