Transcriptome sequencing analysis of two different genotypes of Asian pear reveals potential drought stress genes

'Huangguan' (HG) and 'Whangkeumbae' (HK) pears are two important Asian pear cultivars in China and South Korea, respectively. In practical production, 'Huangguan' pear is a drought-tolerant genotype while 'Whangkeumbae' pear is drought-sensitive. To uncover the mechanisms underlying pear tree tolerance to drought stress, a comprehensive transcriptome analysis was performed in this study. The results revealed a total of 1185 and 1667 differently expressed genes (DEGs) between control and treated plants of HG and HK pear, respectively. KEGG pathways enrichment analysis revealed that the DEGs were involved in the metabolism and signal transduction of various phytohormones. In HG, the DEGs annotated as ABA, gibberellic acid (GA), and salicylic acid (SA) were all upregulated, while those DEGs annotated as jasmonic acid (JA) were upregulated or downregulated. In HK, the DEGs annotated as ABA and JA were both upregulated or downregulated, but there were no DEGs annotated as GA and SA. In addition, there were 743 DEGs expressed in HG, but not in HK. Among them, there were 288 DEGs whose absolute values of log(2)(fold-change ratio) were greater than 2. Eight of the 288 DEGs were selected randomly for validating the reproducibility and accuracy of the transcriptome RNA-Seq data by using quantitative-PCR. Our results will be helpful for breeding drought-tolerant pear cultivars.