Differential gene expression and epigenetic analyses between striped and blushed skinned sports of ‘Fuji’ apple

• Published in: Scientia horticulturae 2020-02, Vol.261, p.108944, Article 108944
• Main Authors: Cho, Hye Jeong, Kim, Gi Hoon, Choi, Cheol
• Format: Article
• Language: English
• Subjects: Anthocyanin; Apple; Carotenoid; Gene expression; Methylation analyses; Skin pattern; Somatic variation
• ISSN: 0304-4238; 1879-1018
• DOI: 10.1016/j.scienta.2019.108944

•The value of L* is lower and a*/b* is higher in blushed fruits of ‘Beni Shogun’ than striped fruits of ‘Fuji’.•MdZISO, MdCRTISO, and MdLCY-ε genes were associated with ground color of Fuji strains at mature stages.•The expression levels of MdMYB10 and MdGST genes were remarkably higher in ‘Beni Shogun’ (blushed skin) than in ‘Fuji’ (striped skin).•Reduced methylation in MR7 of MdMYB10 promoter region is probably associated with the blushed pattern cultivar. The ‘Fuji’ apple is a very popular cultivar because of its high inner quality, and the fruits have an attractive striped pattern. Interestingly, ‘Beni Shogun’, its color enhanced somatic mutant, exhibits a blushed skin, but little is known about the mechanisms that lead to this different skin patterning. In this study, ‘Fuji’ and ‘Beni Shogun’ apples were characterized at five developmental stages. The expression of pigment biosynthesis genes that are responsible for the ground and superimposed skin colors was evaluated. Our L* and a*/b* values data indicates that the blushed skin color of ‘Beni Shogun’ fruits is associated with more anthocyanin accumulation than in the striped skin color of ‘Fuji’ fruits. This can be explained especially by a higher level of MdMYB10 transcript in ‘Beni Shogun’, which activates expression of structural genes encoding enzymes of the anthocyanin biosynthetic pathway. It is also seen the connection between reduced methylation of MR7 of seven randomly divided MdMYB10 promoter and increased fully redness in the ‘Beni Shogun’ skin.