NO way to treat a cold

Temperature is one of the crucial factors that determines plant survival and distribution on the Earth. Various plant species acquire enhanced freezing tolerance by cold acclimation in which prior exposure to low, but nonfreezing, temperatures boosts the chances of surviving subsequent freezing events. Various physiological and biochemical changes take place during the cold acclimation, for example, an increase in osmolites, such as proline (Zhao et al., 2009), and ice-crystal formation in intercellular spaces (Ashraf & Foolad, 2007). These changes are reflected in a massive reprogramming of both the transcriptome and the metabolome (see e.g. Guy et al., 2008 and Thomashow, 2010 for recent reviews). Now, in this issue of New Phytologist, Cantrel et al. (pp. 415–427) have clearly established nitric oxide (NO) as a key player in the plant response to cold stress and have demonstrated that it plays a central role in modulating the synthesis of sphingolipid signals. Based on these insights, novel strategies to improve cold tolerance in plants may be expected.