Metabolic changes of peanut (Arachis hypogaea L.) buds in response to low temperature (LT)

In the present study, we report a metabolomics analysis on peanut buds to delineate metabolic changes at LT using gas chromatography time-of-flight mass spectrometry (GC-TOF/MS). Principle component analysis (PCA) determined overall metabolite alterations. It was found that more metabolites were up-regulated (78.1%) than down-regulated (21.9%). Enrichment of the KEGG pathway indicated that 18 metabolic pathways were significantly changed in peanut buds in response to LT. Compared with the metabolites of peanut buds before LT, there were 73 differentially expressed metabolites detected in peanut buds grown at 25 °C for 12 h, and those metabolites that were up-regulated (50.7%) were similar to those that were down-regulated (49.3%). There were 90 differentially expressed metabolites detected in peanut buds grown at 25 °C for 24 h, the types of up-regulated metabolite (60%) exceeded those that were decreased (40%). The result indicated that with peanut buds to restore growth, most of metabolites which accumulated in response to LT decreased quickly. However, some metabolites (e.g., phytosphingosine, proline, putrescine, and turanose) remained elevated as compared to those before LT, which may contribute to cold tolerance of plants. Observations provide a basis for further elucidation of the molecular physiological mechanism in peanut buds in response to LT.