Reactive oxygen species produced via plasma membrane NADPH oxidase regulate anthocyanin synthesis in apple peel

Abstract

Solar ultraviolet irradiation regulates anthocyanin synthesis in apple peel by modulating the production of reactive oxygen species via plasma membrane NADPH oxidase instead of other pathways. The synthesis of anthocyanin in apple peels is dependent upon solar irradiation. Using 3-mm commercial glass to attenuate solar UV-A and UV-B light, we confirmed that solar UV irradiation regulated anthocyanin synthesis in apple peels after exposing previously bagged fruit to sunlight. During sunlight exposure, UV attenuation did not affect the expression of MdHY5, MdCOP1, or MdCRY2, but significantly lowered plasma membrane NADPH oxidase activity and superoxide anion concentrations. UV attenuation also reduced the expression levels of MdMYB10, MdPAL, MdCHS, MdF3H, MdDFR, MdANS and MdUFGT1, UDP-glycose:flavonoid 3-O-glycosyltransferase (UFGT) activity, and local concentrations of anthocyanin and quercetin-3-glycoside. In contrast, exogenous application of hydrogen peroxide could enhance anthocyanin and quercetin-3-glycoside synthesis. Xanthophyll cycle pool size on a chlorophyll basis was higher but its de-epoxidation was lower under direct sunlight irradiation than that under UV-attenuating conditions. This suggests that reactive oxygen species (ROS) produced in chloroplast are not major contributors to anthocyanin synthesis regulation. Inhibition of plasma membrane NADPH oxidase activity lowered the production of ROS through this mechanism, significantly inhibited the synthesis of anthocyanin, and increased the total production of ROS in apple peel under direct sunlight irradiation, suggesting that ROS produced via plasma membrane NADPH oxidase regulates anthocyanin synthesis. In summary, solar UV irradiation regulated anthocyanin synthesis in apple peels by modulating the production of ROS via plasma membrane NADPH oxidase.

NADPH Oxidases: The Vital Performers and Center Hubs during Plant Growth and Signaling

“…Besides functioning in the regulation of pollen germination, root development and seed germination, as well as fungal development, NOXs/RBOHs have other effects as well. It was suggested that solar ultraviolet irradiation regulates anthocyanin synthesis in apple peel by modulating the production of ROS via NADPH oxidase [64]. Moreover, chloroplastic NADPH oxidase-like activity mediates perpetual H 2 O 2 generation, which probably induces apoptotic-like cell death of B. napus leaf protoplasts [65].…”

Reactive Oxygen Species Acts as an Important Inducer in Low-temperature-induced Anthocyanin Biosynthesis in Begonia semperflorens

“…Chloroplastic H 2 O 2 may activate FAH1 expression to induce anthocyanin accumulation (Maruta et al, 2014). If ultraviolet light is attenuated, the O 2 •concentration and the expression of anthocyanin biosynthesisassociated genes is reduced in apple peel (Zhang et al, 2014). ABA-induced H 2 O 2 is required for anthocyanin accumulation in the leaves of rice seedlings (Hung et al, 2008).…”

“…The production of ROS from plasma-membranelocalized NADPH oxidase plays an important role in ultraviolet ray (ultraviolet)-induced anthocyanin biosynthesis. If ultraviolet light is attenuated, the O 2 Áconcentration is reduced by the expression of anthocyanin biosynthesis-associated genes in Malus ·domestica peel (Zhang et al, 2014). Chloroplastic H 2 O 2 may also activate FAH1 expression to induce anthocyanin accumulation (Maruta et al, 2014).…”

The OsmiR396–OsGRF8–OsF3H‐flavonoid pathway mediates resistance to the brown planthopper in rice (Oryza sativa)

“…Flavonoid biogenesis and/ or their regulatory pathway are involved in the resistance to various stresses, such as high and ultraviolet lights, low temperature, salinity, high sucrose and oxidation (Bharti et al, 2015;Ilk et al, 2015;Kusano et al, 2011;Lotkowska et al, 2015;Mahmood et al, 2016;Zhang et al, 2015). Flavonoids are powerful deoxidizers that relieve oxidative stress (Nakabayashi et al, 2014;Zhang et al, 2014), and respond quickly to different stresses (Dixon and Paiva, 1995). Plants may use flavonoids to deter the feeding, development and oviposition of herbivores (Onkokesung et al, 2014).…”