Assay for transposase accessible-chromatin with high throughput sequencing (ATAC-seq) analysis the molecular responses of postharvest pear during Penicillium expansum infection

Blue mold decay caused by Penicillium expansum is a global destructive postharvest disease, which has brought huge economic losses to the pear industry. Transcription factors play an important role in pear anti-infection defense, and it has been observed that they have multiple functions. However, the roles of numerous TFs in the defense of pear against P. expansum have not been adequately explored. In this study, ATAC-seq was used to screen the TFs of pear against P. expansum, thereby understanding the chromatin-mediated gene regulation in the defense of pear against infection. The peak of differential expression enriched 9 transcription factors (AGL27, AT5G02460, AT2G28810, AT5G66940, AT3G46070 and OBP1, TCP3, BPC1 and TCP17). The up-regulated genes in our study were implicated in the MAPK signaling pathway-plant, plant hormone signal transduction pathway, plant-pathogen interaction pathway, glutathione metabolism pathway, phenylpropanoid biosynthesis, flavonoid biosynthesis pathway and carotenoid biosynthesis pathway were identified. Especially the transcription factors TGA, gene SAUR and CYCD3 in plant hormone signal transduction pathway and NCED, CYP707A in carotenoid biosynthesis pathway were differentially regulated. RT-qPCR analysis of twelve randomly selected differentially expressed peak-related genes confirmed the accuracy of ATAC-seq analysis of P. expansum infected pear.