Abstract
In Arabidopsis, UV and blue light stimulate expression of anthocyanin biosynthesis gene. In the strawberry Fragaria ananassa, UV light increases the red coloration in receptacle, whereas the effect of blue light or other wavelength is not reported yet. In this study, we examined the effect of irradiation on the red coloration of strawberry (cv. Sachinoka) by using various wavelength of LED. 24 h after irradiation of LED and incubated for 36 h in darkness, we measured anthocyanin content. As a result, 465 nm of blue LED irradiated fruits increased 3-fold amount of anthocyanin than green LED (525 nm) or red LED (625 nm) irradiation.
In addition, we examined functional analysis of blue light photoreceptor genes, phototropin (phot) and cryptochrome (cry), by agrobacterium-mediated RNA interference (RNAi). We observed the reduction of red color in the epidermis and the internal region of receptacle in the RNAi fruits compared with control fruits. We found that anthocyanin content in the RNAi fruits was lower than controls (control 100%, phot 56%, cry 45%).
These results indicate that both photoreceptors may be involved in anthocyanin biosynthesis pathway in the strawberry fruit.
