Identification and Analysis of Gene Family Members in .

Polyphenol oxidase (PPO) is a common metalloproteinase in plants with important roles in plant responses to abiotic and biotic stresses. There is evidence that PPOs contribute to stress responses in . In this study, PPO gene family members in were comprehensively identified and characterized using bioinformatics methods as well as analyses of phylogenetic relationships, gene and protein structure, codon usage bias, and gene expression in response to stress. The genome contained 10 PPO gene family members encoding 406-593 amino acids, with a G/C bias. Most were localized in chloroplasts. The motif structure was conserved among family members, and α-helices and random coils were the dominant elements in the secondary structure. The promoters contained many cis-acting elements, such as auxin, gibberellin, salicylic acid, abscisic acid, and photoresponsive elements. The formation of genes in this family was linked to evolutionary events, such as fragment replication. Real-time quantitative PCR results showed that , , , , , , , and may be key genes in drought stress resistance. , , , and were resistant stress-sensitive genes. These results provide a reliable basis for fully understanding the potential functions of these genes and the selection of resistance breeding.