[Construction and preliminary analysis of subtractive library for peel pitting of 'Fengjie' navel orange fruit].

Abstract

In this study, the pitted peel and non-pitted peel of 'Fengjie' navel orange fruits were used as experimental materials to construct and screen the peel pitting related genes by suppression subtractive hybridization (SSH). The results showed that suppression subtractive hybridization was very effective. A cDNA library of differentially expressed genes was constructed. The library included about 200 clones with an average insert size of around 300 bp. Part of the positive clones were picked up randomly and sequenced. Six of the 50 clones had no homologous sequences being found and three had unknown functions in GenBank. According to the analysis of the homology, four homologous (Ca2+ binding protein, cysteine proteinase, NAC-domain protein and expansin) genes were chosen to examine their expressions through semi-quantitative RT-PCR analysis in pitted and non-pitted navel orange fruits. The expression of four genes were all higher in pitted peel than that in non-pitted peel. It suggests that these genes in the SSH cDNA library may be involved with peel pitting and can be subject of future investigation to explore the molecular biological mechanism of the pitting of citrus fruit.