Integration profiling of transcriptome and metabolome reveals the effect of hydrogen peroxide on nucleic acid metabolism in postharvest broccoli during storage

To understand the effects and related molecular regulation mechanism of H2O2 on nucleic acid metabolism in yellowing and senescence process of postharvest broccoli, an integration profiling of transcriptome and metabolome was performed. Results showed that 2 mM H2O2 delayed the yellowing and increase of relative conductivity, whereas 3 μM diphenylene iodonium (DPI, an inhibitor of H2O2 production) accelerated these processes·H2O2 treatment promoted DNA replication and repair by up-regulating replication protein A, DNA polymerase, and DNA ligase 1 expressions and increasing the essential building blocks of DNA (e.g., cytosine, guanosine 5′-diphosphate, cytidine, and adenosine) contents, thereby ensuring the integrity of genome in broccoli·H2O2 treatment promoted transcription and pre-mRNA processing by up-regulating the expressions of RNA polymerases and spliceosome-related genes, which promoted the biosynthesis of mature mRNA·H2O2 treatment also up-regulated PABPs expression, and thus to promote translation process in broccoli. Additionally, H2O2 promoted the recycle of mRNA and accumulation of adenosine, which was beneficial to timely change own gene profile in response to complex postharvest environmental changes and alleviate the energy deficiency suffered by postharvest broccoli. These results suggested that H2O2 is involved in the positive regulation of nucleic acid metabolism and maintained higher contents of nucleic acid-related metabolites, DNA and RNA, ultimately delaying the senescence of postharvest broccoli, which provided new insight for the regulatory mechanism of the yellowing and senescence in broccoli.