Proteomics analysis reveals post-translational mechanisms for cold-induced metabolic changes in XXXX .

@entity7969 @entity958 @entity25409 @entity1735 @entity969 @entity6626 @entity413
Cold-induced changes of gene expression and metabolism are critical for plants to survive freezing. Largely by changing gene expression, exposure to a period of non-freezing low temperatures increases plant tolerance to freezing-a phenomenon known as cold acclimation. Cold also induces rapid metabolic changes, which provide instant protection before temperature drops below freezing point. The molecular mechanisms for such rapid metabolic responses to cold remain largely unknown. Here, we use two-dimensional difference gel electrophoresis (2-D DIGE) analysis of sub-cellular fractions of @entity958 proteome coupled with spot identification by tandem mass spectrometry to identify early cold-responsive proteins in @entity958 . These proteins include four enzymes involved in starch degradation, three HSP100 proteins, several proteins in the @entity6626 cycle, and @entity969 metabolism. Upon cold treatment, the @entity25409 ( @entity25409 ), a cytosolic transglucosidase metabolizing maltose to @entity413 , increased rapidly in the centrifugation pellet fraction and decreased in the soluble fraction. Consistent with cold-induced inactivation of @entity25409 enzymatic activity, the @entity25409 mutant showed increased freezing tolerance without affecting the C-repeat binding transcription factor (CBF) transcriptional pathway. These results support a model that cold-induced inactivation of @entity25409 leads to rapid accumulation of @entity7969 , which is a cold-induced compatible solute that protects cells from freezing damage. This study provides evidence for a key role of rapid post-translational regulation of @entity1735 metabolic enzymes in plant protection against sudden temperature drop.
