The Methylation of the PcMYB10 Promoter Is Associated with Green-Skinned Sport in Max Red Bartlett Pear

• Published in: Plant physiology (Bethesda) Vol. 162; no. 2; pp. 885 - 896
• Main Authors: Wang, Zhigang, Meng, Dong, Wang, Aide, Li, Tianlai, Jiang, Shuling, Cong, Peihua, Li, Tianzhong
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.06.2013
• Subjects: Agrobacterium tumefaciens - genetics; anthocyanins; Anthocyanins - metabolism; Biological and medical sciences; Biosynthesis; Chlorophylls; Cloning, Molecular; color; DNA Methylation; Fruit - physiology; fruits; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Regulation, Plant; Gene Silencing; Genes; GENES, DEVELOPMENT, AND EVOLUTION; Genetic mutation; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; Methylation; Molecular Sequence Data; pears; Peels; Pigmentation; Pigmentation - genetics; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; Promoter regions; Promoter Regions, Genetic; Pyrus - genetics; Pyrus - physiology; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Promoter; Pear; Plant physiology; Methylation
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.113.214700

Varieties of the European pear (Pyrus communis) can produce trees with both red-and green-skinned fruits, such as the Max Red Bartlett (MRB) variety, although little is known about the mechanism behind this differential pigmentation. In this study, we investigated the pigmentation of MRB and its green-skinned sport (MRB-G). The results suggest that a reduction in anthocyanin concentration causes the MRB-G sport. Transcript levels of PcUFGT (for UDP-glucose:flavonoid 3-O-glucosyltransferase), the key structural gene in anthocyanin biosynthesis, paralleled the change of anthocyanin concentration in both MRB and MRB-G fruit. We cloned the PcMYB10 gene, a transcription factor associated with the promoter of PcUFGT. An investigation of the 2-kb region upstream of the ATG translation start site of PcMYB10 showed the regions -604 to -911 bp and -1,218 to -1,649 bp to be highly methylated. A comparison of the PcMYB10 promoter methylation level between the MRB and MRB-G forms indicated a correlation between hypermethylation and the green-skin phenotype. An Agrobacterium tumefaciens infiltration assay was conducted on young MRB fruits by using a plasmid constructed to silence endogenous PcMYB10 via DNA methylation. The infiltrated fruits showed blocked anthocyanin biosynthesis, higher methylation of the PcMYB10 promoter, and lower expression of PcMYB10 and PcUFGT. We suggest that the methylation level of PcMYB10 is associated with the formation of the greenskinned sport in the MRB pear. The potential mechanism behind the regulation of anthocyanin biosynthesis is discussed.