Aroma-related Gene Mining In Labrusca-flavored Grapes Based On Transcriptome Sequencing And QTL Mapping

Aroma is one of the important indicators of grape（Vitis vinifera L.）fruit quality.Grape varieties with different aromas have different characteristic aroma components.The current research on grape aroma mainly focuses on the characteristic aroma substances of muscat cultivar grapes,and there is little research on the characteristic aroma substances of labrusca-flavored grapes.This study uses QTL mapping and transcriptome analysis to mine the candidate genes related to the aroma of labruscaflavored grapes,which has important theoretical and practical significance for the future breeding of labrusca-flavored grapes.In this experiment,30 grape varieties and the hybrid progeny of’‘Zhuosexiang’ × ‘Red Globe’ were used as test materials.Through qualitative and quantitative analysis of their aroma substances,the characteristic aroma components of labrusca-flavored grapes were screened out,and then the characteristic aroma components were analyzed in the hybrid population.In QTL mapping,screening of candidate genes related to labrusca flavor characteristic aroma substances,through transcriptome sequencing,mining candidate genes related to labrusca flavor aroma substance metabolism and synthesis,and gene function analysis.The main test results are as follows:1.It was clear that the main aroma substances are respectively aldehydes,terpenes and esters in neutral cultivar,muscat cultivar and labrusca flavor grape varieties.Through the principal component analysis of the main aroma substances,the grape aroma evaluation model was established,and it was found that the neutral cultivar,muscat cultivar and labrusca flavor grape varieties had the highest respectively comprehensive scores for aroma evaluation,were ‘Victoria’,‘Muscat Grace’ and ‘Queenora Seedless’;2.It is selected that the characteristic aroma substances of labrusca flavor grapes are ethyl acetate,ethyl butyrate,methyl anthranilate,ethyl anthranilate and alpha-terpineol,and these five characteristic aroma substances are used in QTL mapping was performed in the hybrid population constructed by ‘Zhuosexiang’ × ‘Red Globe’,and a total of 14 QTL loci related to the characteristic aroma substances of labrusca flavor grapes were located in 2,3,4,8,and 11.13,15,17,and 18 linkage groups,among which linkage groups 2,8,and 15 are all mapped to QTLs related to ethyl butyrate and ethyl acetate;3.Transcriptome sequencing was performed on the fruits of ‘Zhuosexiang’ and ‘Red Globe’ in different periods,and 13 genes related to the synthesis of aroma substances in labrusca flavor grapes were screened.AAT₂,AAT₃ and LOX₂ may be related to the synthesis of ethyl butyrate;AAT₄ may be related to the synthesis of methyl anthranilate,ethyl 3-hexenoate and ethyl acetate;ADH may be related to the synthesis of phenylethyl alcohol;AAT₁,AAT₉ and HPL may be related to the synthesis of ethyl acetate,ethyl butyrate,methyl anthranilate and α-terpineol;LOX₁ may be related to the synthesis of（e）-2-Hexanal.