A Global Identification of Protein Disulfide Isomerases from 'duli' Pear () and Their Expression Profiles under Salt Stress.

Protein disulfide isomerases (PDIs) and PDI-like proteins catalyze the oxidation and reduction in protein disulfide bonds, inhibit aggregation of misfolded proteins, and participate in isomerization and abiotic stress responses. The wild type 'duli' pear () is an important rootstock commonly used for commercial pear tree grafting in northern China. In this study, we identified 24 genes, named , from the genome of 'duli' pear. With 12 homologous gene pairs, these 24 distribute on 12 of its 17 chromosomes. Phylogenetic analysis placed the 24 PbPDIs into four clades and eleven groups. Collinearity analysis of the between , , and revealed that the of 'duli' pear show a strong collinear relationship with those from Arabidopsis, a dicot; but a weak collinear relationship with those from rice, a monocot. Quantitative RT-PCR analysis showed that most of the were upregulated by salt stress. Identification and expression analysis of 'duli' pear under salt stress conditions could provide useful information for further research in order to generate salt-resistant rootstock for pear grafting in the future.