The role of antifreeze proteins in the regulation of genes involved in the response of Hosta capitata to cold

Cold temperatures are a major source of stress for plants and negatively impact crop yield. A possible way to protect plants is to treat them with antifreeze proteins (AFPs). Here, we investigated whether fish AFPs can shield the rare ornamental species Hosta capitata from low-temperature stress. We elucidated the expression patterns of the cold-inducible genes C-repeat binding factor 1 (CBF1) and dehydrin 1 (DHN1), as well as the antioxidant genes superoxide dismutase (SOD) and catalase (CAT). All were upregulated at low temperature (4 °C). With increasing exposure time, CBF1 and DHN1 expression generally rose (except CBF1 at 48 h). In contrast, SOD and CAT expression gradually declined from 6 to 48 h. Depending on exposure duration, AFP regulation of gene transcription varied with concentration. However, compared with other concentrations, 100 µg/L AFP reduced CBF1 and DHN1 expression and increased SOD and CAT expression in plants, regardless of exposure time. Both AFP I and III were likely to be most effective at protecting plants against cold stress at concentrations of 100 µg/L. Their involvement in H. capitata cold-stress treatment occurred through regulating the expression of important stress-response genes.