Transcriptome and genome analysis to identify C2H2 genes participating in low-temperature conditioning-alleviated postharvest chilling injury of peach fruit

Abstract

Abstract Objectives This work intended to identify candidate C2H2 genes participating in low-temperature conditioning (LTC)-alleviated postharvest chilling injury of peach fruit. Materials and Methods For LTC treatment, fruit were pre-stored at 10 °C for 5 d and then transferred to 0 °C storage. Fruit firmness was measured by a hardness tester. H2O2 content was determined by luminosity measurement model using a multifunctional enzyme labeler. Identification of C2H2 family members was performed by HMMSCAN according to peach genome. The cis-acting element of gene promoters was analyzed using the Plant CARE website. Weighted gene coexpression network analysis (WGCNA) was performed by the WGCNA package in the BMK Cloud platform. Results LTC treatment decreased flesh browning rate and H2O2 production of ‘Beijing No. 9’ peach. Transcription factor identification of differentially expressed genes in 0 °C and the LTC treatment indicated that peach C2H2 participated in the regulation of chilling injury. A total of 47 C2H2 genes were identified based on peach genome. Real-time quantitative polymerase chain reaction (qRT-PCR), phylogenetic analysis and promoter cis-acting element analysis revealed that ZFP21 was involved in the regulation of LTC-alleviated chilling injury in peach. WGCNA and dual luciferase assay suggested that ZFP21 participated in LTC-alleviated chilling injury by downregulating the expression of reactive oxygen species-related genes Rboh. Conclusions Our investigation, based on genome and RNA-seq, revealed that ZFP21 was involved in LTC treatment-alleviated chilling injury of peach fruit. This work is useful for the identification of peach cold tolerance-related genes and the study of C2H2 family in peach.