Abstract: Polygalacturonase (PG, EC3.2.1.15) is the key cell wall hydrolase in fruit ripening. The identification and characterization of a full-length cDNA(pMT18) encoding for PG from Feicheng peach ( Prunus persica (L.) Batsch cv. Feicheng) is described. The pMT18 clone is 1 188 bp in length, with an open reading frame of 393 amino acids. The homology and phylogenetic analyses indicate a remarkable similarity between peach PG and other ripening-related PG. And seven consensus sequences have revealed in peach PG compared to the PG from other plants. However, the profound divergence with other PG and the unique structure features suggest that peach PG probably belongs to a new evolutionary class. In RT-PCR analysis, pMT18-related RNA was undetectable in leaves, and was much abundant in ripe fruits. The ripening-specific expression pattern of this cDNA will be useful in investigating the roles of PG in fruit ripening and developing a transgenic peach with the improved pest-harvesting quality in the future.

Key words: Prunus persica, Polygalacturonase, cDNA, Fruit ripening