A study recently published in Nature Plants by Prof. Julio Salinas, principal investigator of the Plant Molecular Biology Laboratory at Centro de Investigaciones Biológicas (CSIC), identifies for the first time the molecular mechanism by which the NPR1 (Non-expresser of Pathogenesis-Related genes 1) regulator activates cold acclimation, an adaptive process whereby during fall, many plants prepare to winter by increasing their freezing tolerance in response to low non-freezing temperatures.
Using a multidisciplinary experimental approach with Arabidopsis as plant model system, the study, result of an international collaboration, demonstrates that in response to low non-freezing temperatures, cytoplasmic NPR1 oligomers release monomers which translocate to the nucleus where they interact with HSFA1 (Heat Shock Transcription Factor 1). This interaction, in turn, promotes the induction of numerous HSFA1-regulated genes, many of them encoding chaperones - proteins that assist to folding of others - that would act as powerful buffers to minimize the impact of freezing temperatures, and would be essential for the full development of the cold acclimation process.
NPR1 is well known for its critical role in regulating the plant response to pathogens, conferring immunity to the plants through a transcriptional cascade mediated by salicylic acid and TGA transcription factors. The new findings reported in the study led by Prof. Salinas place NPR1 as a central hub integrating cold and pathogen signaling for a better adaptation of plants to their ever-changing environment, opening the avenue for future studies that may allow the development of new biotechnological strategies to generate crop varieties with improved tolerance to challenging environmental conditions.
Reference: NPR1 mediates a novel regulatory pathway in cold acclimation by interacting with HSFA1 factors. Ema Olate, José M. Jiménez-Gómez, Loreto Holuigue, Julio Salinas. Nature Plants (2018). https://doi.org/10.1038/s41477-018-0254-2
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