Induction of flavonoids and phenolic acids in apple by UV-B and temperature

Reflective mulch enhances ripening and health compounds in apple fruit

“…Anthocyanin and flavonoid synthesis is regulated by the enzyme phenyl ammonium lyase (PAL), a key enzyme of the phenylpropanoid pathway. The transcription of this enzyme can be upregulated in apple by certain combinations of abiotic exogenous factors such as light (photosynthetically active radiation PAR and/or UV) as well as temperature . A lack of transcription of the phenylpropanoid pathway genes was responsible for reduced anthocyanin biosynthesis and a transcription factor (MYB10) essential for the anthocyanin biosynthesis .…”

Transcriptional regulation of the flavonoid pathway in the skin of dark-grown ‘Cripps’ Red’ apples in response to sunlight

“…In fruit bagging experiments, levels of quercetin glycosides and CTs have been found to increase after reexposure of the red cultivars 'Delicious' and 'Ralls' to sunlight (Ju, 1998;Ju et al, 1997); however, this does not seem to be a general feature of apple cultivars. For example, Lancaster et al (2000) found that in detached fruit, harvested at five 2-week intervals, quercetin glycosides could be induced by UV-B in shaded skin from the cultivars 'Gala', 'Royal Gala' and 'Braeburn', but not from 'Pacific Rose' and 'Aurora', while CT synthesis was not induced in any of these cultivars. Analysis of transcript levels of the branch pathway genes required for flavonol and CT synthesis may elucidate why different cultivars respond differently to light in terms of flavonol and CT synthesis.…”

Relationships between Surface Blushing and Qualitative Components of Japanese Apricot (Prunus mume Sieb. et Zucc.) ‘Nanko’ Fruit

“…Further, UV light plays an important role in the anthocyanin synthesis of apple (Arakawa, 1988(Arakawa, , 2000Kubo et al, 1988), sweet cherry (Arakawa, 1993;Kataoka et al, 1996), peach (Kataoka and Beppu, 2004), and grape (Kataoka et al, 2003). UV-B irradiation enhanced the phenolic acid content of harvested apple fruit (Lancaster et al, 2000), and UV-C irradiation enhanced the phenolic content and antioxidant activity of harvested strawberry fruit (Erkan et al, 2008). Our results showed that UV light contributed profoundly to the expression of red, phenolic content, and antioxidant activity in Japanese apricot fruit.…”