Seasonal Dormancy of Flower Buds in Japanese Apricot (Prunus mume)

Transcriptomic and proteomic analyses of the role of gibberellin (GA₄) in the acceleration of dormancy release in flower buds of Japanese apricot, Prunus mume, have been reported, but metabolic changes brought about by GA₄ remained to be determined. The present study was undertaken to assess changes in metabolites in response to GA₄ treatment using GC-MS and Principal Component Analysis (PCA). Following GA₄ treatment, 55 metabolites that showed a two-fold difference (P<0.05) between samples taken across time for a given treatment, or between the two treatments were studied further. These metabolites could be mainly categorized into six groups: amino acids and their isoforms (10); amino acid derivatives (7); sugars and polyols (14); organic acids (12); fatty acids (4); and others (8) that are involved in various metabolic pathways, in particular, galactose metabolism, glyoxylate and dicarboxylate metabolism, and starch and sucrose metabolism. These results confirm our previous conclusion that energy metabolism is important in dormancy release following GA₄ treatment at the metabolic level. We also found that proline and sucrose levels can be used as a potential biomarker for understanding the process of dormancy. The current research extends our understanding of the mechanisms involved in budburst and the release of dormancy by GA₄, and provides a theoretical basis for applying GA₄ to break dormancy.