Abstract
A previous study showed that high air temperature causes poor fruit coloration in strawberries ‘Sachinoka’ (Fragaria ×ananassa Duch). So, to investigate the precise effect of high air temperature on pigment loss, we compared strawberry plants grown in growth chambers under a high air temperature (30/15°C, 14/10 h, day/night) regime and a control (20/15°C, 14/10 h, day/night). The harvested fruits were divided into three sections, skin, flesh, and pith, prior to analysis. First, we measured the anthocyanin concentration in the different fruit sections grown under both temperature regimes. We found that the anthocyanin concentration decreased under the high air temperature regime, especially in the fruit skin and flesh. Then, we analyzed the expression levels of the genes for anthocyanin biosynthesis enzymes and their regulators. In the plants exposed to high air temperature, the expression of flavonoid pathway genes and FaMYB10 in the fruit skin and flesh became lower. In particular, four genes (FaDFR, FaANS, FaUFGT, FaMYB10) showed a significant decrease. Therefore, these results suggest that the poor coloration may be caused by suppressed expression of the pathway genes and FaMYB10.
