Analysis of differential expression patterns of mRNA and protein during cold- and de-acclimation in Arabidopsis

Overwintering plants are capable of exhibiting high levels of cold tolerance, which is acquired through the process of cold acclimation (CA). In contrast to CA, the acquired freezing tolerance is rapidly reduced during cold de-acclimation (DA) and plants resume growth after sensing warm temperatures. In order to better understand plant growth and development, and to aid in the breeding of cold-tolerant plants, it is important to decipher the functional mechanisms of the DA process.In this study, we performed comparative transcriptomic and proteomic analyses during CA and DA. As revealed by shotgun proteomics, we identified 3,987 peptides originating from 1,569 unique proteins and the corresponding mRNAs were analyzed. Among the 1,569 genes, 658 genes were specifically induced at the transcriptional level during the process of cold acclimation. In order to investigate the relationship between mRNA and the corresponding protein expression pattern, a Pearson correlation was analyzed. Interestingly, 199 genes showed a positive correlation of mRNA and protein expression pattern, indicating that both their transcription and translation occurred during CA. However, 226 genes showed a negative correlation of mRNA and protein expression pattern, indicating that their mRNAs were transcribed during CA and were stored for the subsequent DA step. Under this scenario, those proteins were specifically increased during DA without additional transcription of mRNA. These data indicate that the expression of specific mRNAs and subsequent accumulation of corresponding proteins are not always in accordance under low temperature stress conditions in plants.