Study On Pulp Veraison Of Red Fleshed Grape Based On The Transcriptome Analysis And Anthocyanins Accumulation During The Grape Development

Anthocyanins systhesised from phenylpropanoid pathway are belong to the flavonoids.A lot of researches revealed that anthocyanins could prevent different kinds of diseases,such as cancer and some physiological diseases.Most of red grapes could accumulate anthocyanins in the skin,however the edible part only has trace amount of anthocyanins.So,it is meaningful to study on the color of grape berries in order to improve the grape quality.There is a kind of grape called red fleshed grape could accumulate anthocyanins not only in skin but also in pulp.Red fleshed grapes usually contained lower sugar and smaller in appearance.Because of the high density of anthocyanins,it was often used to make wine.In this study,a newly found red fleshed grape germplasm,ZhongShanHongYu,could also accumulate anthocyanins in both skin and pulp.At present,the anthocyanins biosynthesis pathway in grapes has been confirmed,but the mechanism of pulp veraison is still unclear.Therefore,the molecular and physiological experiments were implemented on ZhongShanHongYu and aimed to provide a theoretical basis for pulp veraison in grape and cultivating high concentrations of anthocyanins grape varieties.The major results were showed as following:1.The sampling stages lasted from 3 weeks after anthesis(3 WAA)to 10 weeks after flowering(mature stage,10 WAA).The longitudinal diameters,cross diameters,weight and fruit qualities were measured during the berry development.The results showed that the longitudinal diameters of berries showed ’double S’ curve during the berry development,while the cross diameters showed ’single S’ curve.In the lag phase stage,about 5 to 6 WAA,the soluble solids was significantly increased and titrate acid was decreased at the same time.Besides,the anthocyanins composition in the skin and pulp of ZhongShanHongYu and Summer Black was identified by HPLC-MS.The all of anthocyanins in ZhongShanHongYu were monoglucoside or monogalactoside and the anthocyanins content in ZhongShanHongYu was significantly higher than Summer Black.Interestingly,pelargonidin barely contained in the cultivar Vitis Vinifera was detected in the peel and pulp of ZhongShanHongYu.2.In order to further explore the mechanism of the pulp veraison in ZhongShanHongYu,the berries have been sampled at 3 days after anthesis(green-pulp,3 DAA),6 days after anthesis(pulp-veraison,6 DAA)and 22 days after anthesis(pulp-half-colored,22 DAA)in 2017.Transcriptome analysis based on the RNA-seq and high-performance liquid chromatography with mass spectrometry(HPLC-MS)were used to analyze the mechanism about anthocyanins biosynthesis.The results of transcriptome analysis showed that 56 candidate genes including 26 regulatory genes and 30 structural genes were selected.Moreover,it was found that the ratio between the di-substituted(cyanidin-and peonidin-)anthocyanins and the tri-substituted(delphinidin-,petunidin-and malvidin-)anthocyanins was consistent with the ratio between the expression levels of F3’H and F3 ’5’H.In KEGG analysis,out of 110 pathways,photosynthesis-antenna proteins and photosynthesis,found significantly enriched in three comparisons and this study provide a potential mechanism between the light response and grape pulp veraison.This work raised some candidate genes related to the anthocyanins biosynthesis through RNA-seq technique and provided a theoretical basis for further studies.3.The sampling stages lasted from 3 weeks after flowering(June 10th,2018,3 WAA)to 10 WAA(July 29th,mature stage)and berry samples were taken every 7 days.The chromatic aberration of berries were measured by a colorimeter and the skin and pulp of berries were separated to identify the composition and content of anthocyanins by HPLC-MS.Besides,12 candidate genes selected from the transcriptome analysis results were used to identify the genes relative expression level by qRT-PCR in the skin and pulp of ZhongShanHongYu.The results showed that the ratio of various anthocyanins were different between skin and pulp and the gene MYBA2 maybe the key factor determining the coloring in pulp of ZhongShanHongYu.