Abstract:The relationship between pectin pethylesterase (PME) genes expression and aril breakdown of longan (Dimocarpus longan Lour.) fruit was studied by using RT-PCR and RACE-PCR methods. Three PME cDNA fragments containing 3′UTR (untranslate region), named as DlPME1, DlPME2 and DlPME3, respectively, were cloned from longan fruits. The deduced amino acid sequences of the three DlPMEs genes shared high homology with those of other plants. Moreover, their expression profiles were studied by using semiquantitative RT-PCR during aril breakdown of longan fruits. When stored at room temperature, the expression of DlPME1 gradually weakened during aril breakdown of longan fruits, while DlPME3 and DlPME2 transcripts increased progressively and then decreased. However, accumulations of DlPME1 and DlPME3 transcripts enhanced firstly, then decreased stored at low temperature (4℃), and DlPME2 transcript continuously decreased. These suggested that the expression patterns of DlPMEs were different during aril breakdown of longan fruits, DlPME2 and DlPME3 might be involved in the aril breakdown of longan fruits stored at room temperature, while DlPME1 and DlPME3 did at low temperature.