Proteomics of European beech (Fagus sylvatica L.) seed dormancy breaking: Influence of abscisic and gibberellic acids

Abstract

A proteomic approach was used to analyze mechanisms of dormancy breaking in beech (Fagus sylvatica L.) seeds and the participation of abscisic and gibberellic acids (ABA and GA) in this process. After imbibition in water, ABA, or GA₃ solutions, beechnuts were subjected to cold stratification, which breaks their dormancy. ABA delayed, whereas GA₃ promoted seed dormancy breaking. Proteome maps for water, ABA, and GA₃ were established, which displayed 1544 silver-stained spots. A total of 74 spots, showing significant changes in volume, were identified by MS. Of these, 18, 45, and 16 spots were identified as water-, ABA-, and GA₃-responsive, respectively (five were regulated by both hormones). The classification of proteins showed that most of the proteins associated with dormancy breaking in water are involved in energy metabolism and protein destination. Most of the ABA-responsive proteins are involved in protein destination, energy metabolism, and development. Most of the GA₃-responsive proteins are involved in energy metabolism (many more than for ABA and water) and plant defense. We conclude that the mechanism of seed dormancy breaking involves the proteins of many processes, beginning with hormone signal initiation, through signal transduction, transcription, protein synthesis, energy metabolism, storage materials, and ending with the cell cycle.