Differentially expressed genes related to the formation of russet fruit skin in a mutant of ‘Dangshansuli’ pear (Pyrus bretchnederi Rehd.) determined by suppression subtractive hybridization

Abstract

The mature fruit skin of ‘Dangshansuli’ pear (Pyrus bretchnederi Rehd.) is yellow-green, but the fruit of the mutant, ‘Xiusu’, is russetted. To understand the mechanism of russet formation, the suppression subtractive hybridization libraries were used to screen for differentially expressed genes between the wild type pear and the mutant. Three hundred and twenty nine and 366 unigenes were obtained from 934 and 929 colonies in the forward and reverse libraries, respectively. The results indicated that phenylpropanoid metabolism, ethylene metabolism and secondary metabolism might be involved in the russet formation process, and fruit skin is likely to be regulated by lignin synthesis, polyamine and H2O2 signalling. Furthermore, the accumulation of lignin and H2O2, together with up-regulated POD enzyme genes expression in the exocarp of ‘Xiusu’ compare with ‘Dangshansuli’ pear control, provided a comprehensive transcriptomics view on the coordination of the russet formation of mutant pear.