Exploring the impact of blue light on cold acclimation mechanisms in wheat: A comparative analysis of leaf and root responses.

Light spectrum may also affect the stress acclimation processes in plants. The main aim of the present study was to reveal how the additional blue light may affect the stress-related processes in winter wheat (Triticum aestivum L. cv. Mv Béres) under control and cold hardening conditions. Plants were grown under either white or blue light conditions, then cold treatment was carried out either in the same light, or plants were transferred from white to blue or from blue to white light conditions. The chlorophyll-a fluorescence induction data suggested that the used cold acclimation did not cause severe stress; and together with the metabolomics data, they suggest that the temperature acclimation processes are influenced by the spectrum during both the growth and cold acclimating periods. Twelve out of the 77 compounds identified in untargeted metabolite analysis have been described here for the first time, to the best of our knowledge. Quinic acid derivatives substantially increased at low temperature, especially those that were grown under blue light. While most of the agmatine derivatives decreased, the putrescine derivatives increased at low temperatures both in the leaves and roots; however, the effect of spectrum was less obvious. Blue light influences cold-induced gene expression, especially in the ICE-CBF-COR pathway, which is essential for freezing tolerance in plants, physiological adaptations, and stress responses at metabolite levels. In conclusion, present results demonstrate that blue light may induce specific cold acclimation processes in wheat leaves, and certain effects of light signals can also be detected in the roots.