Genome-Wide Analysis of the Polygalacturonase Gene Family Sheds Light on the Characteristics, Evolutionary History, and Putative Function of .

Polygalacturonase (PG) is one of the largest families of hydrolytic enzymes in plants. It is involved in the breakdown of pectin in the plant cell wall and even contributes to peel cracks. Here, we characterize and outline their expression profiles using the available reference genome and transcriptome of . The average length and exon number of the 47 identified unevenly assigned on 14 chromosomes and two unassembled contigs, were 5399 bp and 7, respectively. The phylogenetic tree of 191 , including 47, 57, 51, and 36 from , , and , respectively, showed that were distributed in all groups except group G and that 10 in group E were older, while the remaining 37 were younger. Evolutionarily, all generally experienced whole-genome duplication (WGD)/segmental repeats and purifying selection. Additionally, the origin of conserved domain III was possibly associated with a histidine residue (H) substitute in motif 8. The results of both the phylogenetic tree and expression profiling indicated that five , especially could be associated with the cracking process. Detailed information and data on the family are beneficial for further study of the postharvest biology of .