Allelotyping of S-RNase Gene and Promoter Region of MdMYB۱۰ Gene in some Genotypes of Apple (Malus spp.)

چکیده مقاله

Introduction: Red-fleshed apples (Malus spp.) are one of the rarest apple genotypes in the world and the accumulation of a high amount of anthocyanin, is the main cause of the redness of their fruit flesh. Anthocyanins are among important flavonoids and due to antioxidative activity, scavenge reactive oxygen species, and hence, are considered as one of the health-promoting nutraceuticals in the human diet. The amount of anthocyanins depends upon the expression of the transcription factors that are regulating their metabolic pathway. Among these transcription factors are the members of the MYB gene family. MdMYB10, belonging to this gene family in apple, has been shown to have a significant role in controlling the amount of anthocyanin production and redness in fruit flesh. The expression of MdMYB10 and consequently, the production of MdMYB10 proteins has positive feedback on its own expression. This happens due to a 23 bp microsatellite tandemly repeated 5 times in its promoter region (called allele R6) which is a target sequence for MdMYB10 acting as a positive regulator. This structure invokes the overexpression of MdMYB10 which in turn increases the expression of anthocyanin producing enzymes and finally the amount of anthocyanin in all organs of the apple plant including fruit flesh. The apple Malus pumila var. Niedzwetzkyana and its derivatives have been reported to have such a structure in the promoter region of the MdMYB10 gene. The length of the R6 allele is 496 bp, while the R1 allele is only 392 bp long. However, in some cases, a locus linked to the S3 allele of the S-RNase gene has been proposed to be …