Physiological And Transcriptional Analysis Of Early Ripening Berry Promoted By Hydrogen Peroxide In ’Kyoho’ Grape Treatment

Previous study exogenous reactive oxygen species（H₂O₂）was used to treat the young berry of’Kyoho’grape,which showed that H₂O₂ treatment could promote the early ripening of’Kyoho’grape berry.Therefore,in the study,different concentrations of exogenous reactive oxygen species（H₂O₂）were sprayed on’Kyoho’young berries to investigate the effect of H₂O₂ treatment on berries ripening and reactive oxygen species metabolism.In order to further investigate the molecular mechanism,which H₂O₂ treatment promoted’Kyoho’grape early ripening,the transcriptome sequencing was employed.Thereby screening out some candidate genes and key pathway of associated with fruit ripening,which laying a foundation for further research on regulation of berries ripening.The main results were as follows:1.100,300 and 500 mmol/L H₂O₂treatment all promoted the early ripening of‘Kyoho’grape,however,the 300 mmol/L H₂O₂treatment was the most effective;Compared to the control,the 300 mmol/L H₂O₂treatment promoted the’Kyoho’early ripening 20 days.2.H₂O₂ treatment affected ROS metabolism and related physiological indexes in‘Kyoho’grape berries.Different concentrations of H₂O₂ have an effect on the diameter of the berry.The diameter of 300 mmol/L H₂O₂was significantly higher than the control and others treatments group at 55-70 days post anthesis.The firmness of different concentrations H₂O₂treatment was significantly higher than the control at 45days post anthesis.The firmness of 300 mmol/L H₂O₂was significantly lower than the control and others treatments group at 70 days post anthesis.The SOD（superoxide dismutase）activity of 300 mmol/L H₂O₂was significantly higher than the control at 35and 70 days post anthesis;The content of anthocyanin,soluble solid,sucrose,H₂O₂and the activity of cellulase,pectinase were significantly higher than the control at 65days post anthesis;The NOX（NADPH oxidase）activity of 300 mmol/L treatment was significantly higher than the control.The O₂ produce rate was significantly higher than the control at 55 days post anthesis;Compared to the control,different concentrations H₂O₂ all increased the content of As A（ascorbic acid）.3.Transcriptome sequencing was employed for 300 mmol/L H₂O₂ treatment sample of’Kyoho’grapes.Transcriptome sequencing showed a total of 40568 and40591 genes were examined in the control groups and the treatment groups,respectively.The Venn diagram indicated that the shared expressed genes in all the control groups and all the treatment were 9035 and 3922,respectively.TCseq analysis was carried out to identify the gene expression trends in different stages;TCseq analysis demonstrated that the expression patterns of most of the genes were similar between them except some genes related to the chlorophyll binding and photosynthesis.According to the p<0.05 and|Log2Fold Change|>1,transcriptome sequencing screened 1089 differentially expressed genes including 406 up-regulation and 683down-regulation;Further,GO enrichment and KEGG pathway analysis of these differential genes revealed that some pathways or functions related to chlorophyll binding and photosynthesis.The WGCNA（weighted gene co-expression network analyses）analysis was carried out to identify the regulatory network between genes in grape berry development and selected some hub genes.Significantly differentially expressed genes and hub genes associated with oxidative stress（HSP）,cell wall deacetylation（GDSL）,cell wall degradation（XTH）,photosynthesis（CAB1）were screened based on the analysis of the TCseq,GO enrichment,KEGG pathway,differentially expressed genes and weighted gene co-expression network analysis,and these genes expression were verified by q RT-PCR.To sum up,different concentration values of H₂O₂ promoted early ripening of Kyoho berries;however,the 300 mmol/L H₂O₂treatment was the most effective;The300 mmol/L H₂O₂ treatment promotes early fruit ripening by affecting oxidative stress（HSP）,cell wall deacetylation（GDSL）,cell wall degradation（XTH）and some genes of photosynthesis pathway.