Gene expression patterns of red color skin in bartlett pear (Pyrus communis) and its bud mutation Max Red Bartlett.

Molecular aspects of the skin colour of ‘Williams’ pear with respect to its muted sport ‘Max Red Bartlett’ have been investigated. Their phenotypes are almost identical except for the fruit colour: yellow in ‘Williams’ and red in ‘Max Red Bartlett’. The skin colour of the latter is more evident since the earliest fruit development stages and then it becomes less intense, while in ‘Williams’ the fruit becomes yellow at ripening stage. Four samples of peel have been collected at different development stages: 45, 60, 90, and 120 days after blooming. Specific primers only for genes of the flavonoid biosynthetic pathway (CHS, CHI, F3H, DFR, ANS, UFGT) and for a Myb transcription factor were used to amplify the cDNA derived from the skin extracted RNAs. Real Time PCR analysis was used to compare the expression levels between ‘Williams’ and ‘Max Red Bartlett’ which differ significantly for ANS, UFGT, and the MYB factor