4. Discussion
It has been shown in many fruits that specific light spectral
wavelengths can influence the biosynthesis of anthocyanins and other
polyphenolic compounds (Jeong et al., 2004; Kokalj et al., 2019; Koyama
et al., 2012; Tao et al., 2018). However, the molecular mechanisms
underlying the light quality regulated fruit anthocyanin biosynthesis
are not well understood. In this study, we used a comparative
transcriptomics approach to analyze the effect of light quality on
anthocyanin biosynthesis in ripening fruit of bilberry producing
anthocyanins from both cyanidin and delphinidin branches. The light
treatments were given to unripe green (S3) bilberry fruits, as this
stage has been shown earlier to be reactive towards changes in spectral
light wavelengths affecting anthocyanin biosynthesis (Zoratti et al.,
2014b). Here, we showed that the anthocyanin concentration and profile
in ripening berries was affected especially by red light but also blue
light treatment, and our results indicate differences in light signaling
pathways between red and blue light in regulation of anthocyanin
biosynthesis.