Effects Of Different Diurnal Amplitude On Plant Growth And Fruit Quality Of Cabernet Sauvignon And Transcriptome Analysis

In this study,the night temperature was regulated by facilities to simulate different day-night temperature differences,and the effects on the growth and development indexes,fruit quality and synthesis-related gene expression of Cabernet Sauvignon were studied.Four groups of different treatments were set,T-2,6℃(night average temperature was 17.0℃),T0.5℃(night average temperature was 20.1℃),T3.5℃(night average temperature was 23.1℃)and CK(night average temperature was 19.6 ℃).Plant growth and development indicators and fruit quality were measured and transcriptome sequencing was performed.The results show that:(1)The small temperature difference between day and night promoted the growth of plant shoots.The increase of temperature difference between day and night was beneficial to the color conversion of grape berries,but too large or too small temperature difference between day and night would inhibit the color conversion of grape berries.(2)The diurnal temperature difference was positively correlated with the contents of soluble solids,soluble sugar,titratable acid,total phenol,total tannin and total anthocyanin.(3)Large diurnal temperature difference is beneficial to the accumulation of most monomeric phenols,but excessive diurnal temperature difference will reduce the content of some monomeric phenols,such as caffeic acid and rutin.Small diurnal temperature difference promotes the accumulation of epicatechins,but too small diurnal temperature difference inhibits the accumulation of epicatechins.(4)Large day-night temperature difference promoted the accumulation of monomer anthocyanin,but excessive day-night temperature difference inhibited the accumulation or even formation of monomer anthocyanin.When the day-night temperature difference was too small,it promoted the accumulation of some monomer anthocyanin,such as petunia pigment and envolvin-3-O-glucoside.(5)Higher diurnal temperature difference promoted the accumulation of aldehydes,esters,alcohols and terpenes in Cabernet Sauvignon fruit,and lower diurnal temperature difference promoted the accumulation of ketones and acids in Cabernet Sauvignon fruit;(6)A total of 5111 differentially expressed genes were detected,among which,1064 differentially expressed genes were detected between T-2.6℃ and CK,830 were detected between T0.5℃ and CK,and 3107 were detected between T3.5℃ and CK;a total of 1252 differentially expressed genes and 119 metabolic pathways were annotated to the KEGG database.As for the metabolic synthesis of aroma,the differentially expressed genes were mainly enriched in linoleic acid,phenylalanine,lysine metabolism,limonene and pinene degradation pathways.(7)Large diurnal temperature difference increased the transcription level of ADH,ASP,TAT and PAL related genes,and small diurnal temperature difference promoted the up-regulation of LOX,HBD,NAAT,AMI,HGO,HPD,8HGO and ALDH related genes.