The Interaction Between MdHIRs Protein And MdJAZs Protein Regulate Anthocyanins Accumulation In Apple

Skin color is one of the most important appearance quality traits, which directly affects commodity value. Skin coloration results from the accumulation of anthocyanins in apple fruits. In apple, anthocyanins are biosynthesized through phenylpropanoid pathway and Flavonoid pathway, which is influenced by multiple factors such as light, tempreture, nutrient availability, phytohormones and so on.In this study, the fruits of apple cultivars ’Red Delicious’ and ’Fuji’(Malus×Domestica Borkh) were used as the materials. Viral vector-mediated transient analysis was conducted to characterize the function of MdJAZ2and MdHIRs in the regulation of anthocyanins accumulation in apple fruits. The main results are shown as follows:1. MdJAZ2inhibited the anthocynin accumulation in apple peelThe viral vector IL60-MdJAZ2was to injected into the fruits of cultivar’Red delicious’. The result showed that the peel coloration around the injection sites was suppressed. Relative expression levels of several anthocyanin biosynthetic genes around the injection sites were remarkably reduced. Therefore, MdJAZ2was as a negative regulator in anthocyanin biosynthesis.2. Interactions of MdJAZs with MdHIRs in Malus domesticaTo verify the interaction of MdJAZ2with MdHIR2that identified from the Y2H screen, this study used Y2H and Pull-Down tests demonstrated the interaction of MdJAZs with MdHIRs.3. The MdHIRs repressed anthocyanin accumulation in apple peelThis study used the virus vector fused gene IL60-MdHIR2, IL60-MdHIR4injected into the apple peel respectively, and the coexpression IL60-MdHIR2with IL60-MdJAZ2, IL60-MdHIR4with IL60-MdJAZ2were injected into the apple peel respectively too, showed the similar phenotype to the injected with MdJAZ2. The anthocyanin accumulation in apple peel was repressed. When the silenced gene MdHIR4which fused with vector TRV was injected into apple peel, the anthocyanin accumulation in apple peel was higher.