The Effects Of GA₃ And CPPU On Fruit Quality And Berry Russet Of 'Shine Muscat' Grapes

The dissertation is to investigate the the effects of different concerntrations of GA3 and CPPU on the fruit quality,pericarp pigmentation degree and berry russet of 'Shine Muscat' grapes and to elucidate the effect of GA3 and CPPU treatment ontiny reddish-brown blotches appear on the surface of berries,molecular approaches were used to explore the underlying molecular mechanisms based on differential transcript expression analysis.The main results were as follows:1.Table grape cultivar 'Shine Muscat' was used as research material in this study.The treatment of 25mg·L-1 GA3 was used at florescence stage,a concentration response was observed over a range of 25mg·L-1 GA3+0 mg·L-1 CPPU?25mg·L-1 GA3+5mg·L-1 CPPU?25mg·L-GA3+10mg·L-1 CPPU?25mg·L-1 GA3+15mg·L-1 CPPU,applied to fruitlets(mean diameter 6 mm)again at 2 weeks after full bloom(WAFB).Set water treated berries as the control,to investigate the effects of different concerntrations of GA3 and CPPU on the fruit quality and pericarp pigmentation degree of 'Shine Muscat' grapes.The results demonstrate that compared with CK,treatments of 25mg·L-1 GA3 with 0 mg·L-1?5 mg·L-'1 10 mg·L-1?15mg·L-1 CPPU significantly improve the fruit longitudinal and horizontal diameter,fruit shape index and average fruit weight,meanwhile can reduce the content of soluble solids and titratable acidity obviously.However,coloring was relatively slow and the fruit ripening stage was delayed with the increase of treatment concentration.From the comprehensive traits of 'Shine Muscat' grapes after treatments with GA3 and CPPU,the treatments of 25 mg·L-1 GA3 in peak florescence and 25 mg·L-1 GA3 + 5 mg·L-1 CPPU at two weeks after full bloom is the most appropriate.2.The present study was carried out to investigate the underlying mechanism of tiny reddish-brown blotches appear on the surface of berries and need to lower down the incidence of fruit rust.Table grape cultivar 'Shine Muscat' was used as research material in this study.A concentration response was observed over a range of 25mg·L-1 GA3+0 mg·L-1 CPPU?25mg·L-1 GA3+5mg·L-1 CPPU?25mg·L-1 GA3+lOmg·L-1 CPPU?25mg·L-1 GA3+15mg·L-1 CPPU,applied to fruitlets(mean diameter 6 mm)at 2 weeks after full bloom(WAFB).Set water treated berries as the control.Treated berries were harvested weekly from color-change period(8 weeks post treatment).The fruit skin browning level,fruit quality and secondary metabolites content in grape peel were determined to study the effect of GA3 and CPPU treatment on the change of skin browning level.The results show that to compare with the control,GA3 combines with CPPU treatment significantly decrease the lignins and total phenol content in pericarp of berries.The content of phenolic acids such as caffeic acid,fenugreek acid and clove acid decreased significantly with the increase of CPPU concentration,While catechin and gallic acid increased first and then decreased with the increase of CPPU concentration.CPPU treatment significantly reduce fruit blotch in the skin and browning level of berries.Present research indicated that CPPU treatment can be an effective method to reduce the skin-browning and enhance the commercial value of berries of'Shine Muscat'.3.To elucidate the effect of GA3 and CPPU treatment ontiny reddish-brown blotches appear on the surface of berries,molecular approaches were used to explore the underlying molecular mechanisms based on differential transcript expression analysis.In present study,We have performed transcriptome and differential transcript expression analyses of 'Shine Muscat' grape berries using the Illumina RNA-Seq system.The transcript expression levels were compared between the 25 mg·L-1 GA3 at full bloom,25 mg·L-1 GA3 combined with 10 mg·L-1 CPPU WAFB and water treated grape berries.Out of approximately 5.53 G clean data and 1186 differentially expressed genes(DEGs)were identified.Gene ontology(GO)function annotate to 3 categories including cell components,molecular functions and biological processes which can be indentified into 30 functional groups.Carbohydrate metabolism and biosynthesis were found the most enriched GO category belonged to Biological process.Analysis of KEGG metabolic pathways demonstrated demonstrated that the most enriched DEGs were associated with 'metabolic pathway' and 'phenylpropanoid synthesis' out of the 126 total pathways.QRT-PCR assay results for 9 selected transcripts validated the data obtained by RNA-Seq?the results were consistent with the sequencing results.The present study found that CPPU treatment reduced reddish-brown blotches appeared on the surface of berries related to the 'phenylpropanoid biosynthesis'and'flavonoid metabolism' pathways.GA3 and CPPU significantly inhibited the gene expression and enzyme activity of these two pathways,reducing the production of secondary metabolites which were the precursors of berry reddish-brown blotches,ultimately inhibit the skin browning of grape berries.