Enhanced multiple stress tolerance in <italic>Arabidopsis</italic> by overexpression of the polar moss peptidyl prolyl isomerase <italic>FKBP12</italic> gene.

Key message: <italic>PaFKBP12</italic> overexpression in <italic>Arabidopsis</italic> resulted in stress tolerance to heat, ABA, drought, and salt stress, in addition to growth promotion under normal conditions.Abstract: <italic>Polytrichastrum alpinum</italic> (alpine haircap moss) is one of polar organisms that can withstand the severe conditions of the Antarctic. In this study, we report the isolation of a peptidyl prolyl isomerase <italic>FKBP12</italic> gene (PaFKBP12) from <italic>P. alpinum</italic> collected in the Antarctic and its functional implications in development and stress responses in plants. In <italic>P. alpinum, PaFKBP12</italic> expression was induced by heat and ABA. Overexpression of <italic>PaFKBP12</italic> in <italic>Arabidopsis</italic> increased the plant size, which appeared to result from increased rates of cell cycle. Under heat stress conditions, <italic>PaFKBP12</italic>-overexpressing lines (<italic>PaFKBP12</italic>-OE) showed better growth and survival than the wild type. <italic>PaFKBP12</italic>-OE also showed higher root elongation rates, better shoot growth and enhanced survival at higher concentrations of ABA in comparison to the wild type. In addition, <italic>PaFKBP12</italic>-OE were more tolerant to drought and salt stress than the wild type. All these phenotypes were accompanied with higher induction of the stress responsive genes in <italic>PaFKBP12</italic>-OE than in the wild type. Taken together, our findings revealed important functions of <italic>PaFKBP12</italic> in plant development and abiotic stress responses. [ABSTRACT FROM AUTHOR]