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

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.