Abstract
We carried out comparative analyses of both metabolites and transcripts using Arabidopsis plants under low-temperature and drought stress conditions and transgenic plants overexpressing DREB1A (35S:DREB1A) and DREB2A (35S:DREB2ACA). Metabolites analyses were performed using GC-TOF-MS, CE-ESI-MS and LC-IT-MS. Identified metabolites were statistically compared by principal component analysis. Then, we selected candidates of critical factors under low-temperature and drought conditions. Transcripts analyses were performed using an Agilent Arabidopsis2 oligo array. We found that genes encoding some of the metabolic key enzymes were induced under low-temperature and/or drought conditions and, a clear correlation was observed between induction of the genes and increments of synthesizing sugars in the plants. In addition, DREB1A was related to the regulation of starch degradation and raffinose synthesis. Using GFP fusion proteins we found that a raffinose synthase encoded by a low-temperature inducible gene was located in chloroplast suggesting that raffinose was accumulated in chloroplast under low-temperature condition.
