Figure 1.

Low-temperature stress represses the accumulation of anthocyanins in strawberry fruits. A, Phenotypes of detached strawberry fruits under low-temperature stress. Diploid strawberry fruits (F. vesca, cv Fragola di Bosco) at the big green, white, and turning stages were fed with 88 mM sucrose at 25°C, 10°C, or 4°C. Photographs were taken every day, and representative images are shown. Bar, 1 cm. B, Strawberry plants carrying three white or turning fruits per plant were placed in a growth chamber set to 25°C (control conditions), 10°C, or 4°C. Photographs were taken every day, and representative images are shown. Bar, 1 cm. C, Phenotypes of strawberry plants carrying white fruits cultivated at 25°C, 10°C, or 4°C for 8 days. Bar, 5 cm. D, Fruits of the cultivar Benihoppe grown at ∼20°C (left) or 4°C (right) in the greenhouse. Bar, 2 cm. E, Relative expression levels of selected regulators involved in anthocyanin biosynthesis in white strawberry fruits at 25°C or subjected to 4°C treatment. Values are means ± standard error of mean (sem) of three biological replicates. Statistical significance was determined by Student’s t test (*P < 0.05, **P < 0.01).