Proteomic analysis of Zanthoxylum nitidum seeds dormancy release: Influence of stratification and gibberellin

Zanthoxylum nitidum (Roxb.) DC. is one of the most important economic crops on account of its value as a Chinese herbal medicine (Zanthoxyli radix), health product and daily chemical raw materials. Zanthoxylum nitidum seeds are characterized to be an intermediate physiological dormancy that requires three months of cold stratification (4 °C) or gibberellin (GA) treatment (300 mg L−1, soaking for two days) to relieve seed dormancy and promote germination. Exploring the changes of proteins and related biosynthetic and metabolic pathways during seed dormancy release will contribute to expand our knowledge of this process. In this study, mature Zanthoxylum nitidum seeds from Pingyuan County, Guangdong province were treated with cold stratification and GA solution. The differently expressed proteins after treatments were characterized by iTRAQ coupled LC-MS/MS. In total, 484 proteins showed that at least 1.3-fold differences in abundance were detected after treatments; a majority of the differently abundant proteins are involved in the respiration-related metabolism processes, biosynthesis of amino acids and translation during the dormancy release of Zanthoxylum nitidum seeds. This study is the first to use the iTRAQ-based proteomics approach to analyse the proteome of Zanthoxylum nitidum seeds, pointing out the direction for our further research on the pathways and even the key genes and proteins associated with the dormancy release of Zanthoxylum nitidum seeds.