Pear (), one of the most widely planted fruit trees in the world, is infected by pear ring rot disease, which is triggered by . Previous research has shown that exogenous calcium enhanced pear resistance to To explore the molecular mechanism of calcium in pear pathogen resistance, we searched the differentially expressed genes (DEGs) between calcium and HO treatment with inoculation in pear by using RNA-seq data. On the basis of the standard of a proportion of calcium/HO fold change >2, and the false discovery rate (FDR) <0.05, 2,812 and 572 genes with significant differential expression were identified between the HO and calcium treatments under inoculation at 2 days postinoculation (dpi) (D2) and 8 dpi (D8), respectively, indicating that significantly more genes in D2 responded to calcium treatment. Results of the gene annotation showed that DEGs were focused on plant-pathogen interactions, hormone signal transduction, and phenylpropanoid biosynthesis in D2. Moreover, transient silencing of (pear calmodulin-like proteins 30), which had significantly higher expression in response to calcium than HO treatments, conferred compromised resistance to . Exogenous calcium treatment slightly alleviated the symptoms of TRV2- leaves compared with TRV2 leaves under inoculation, supporting its key role in pear resistance to . Overall, the information obtained in this study provides a possible mechanism of calcium in regulating pear resistance to .
