The Study On Variation Of Volatile Arom In Grape Germplasm Resources And GWAS Analysis

Grapevine is one of the important fruit trees in the world,which has the important status in the agricultural economy in our country.Aroma content,as one of the important quality traits of the grape berry,is controlled by multiple genes,and easily influenced by genetic background,planting environment and cultivation measures and other factors.To explore the composition and content of volatile aromas in grape germplasm resources,to obtain the candidate genes and related SNP loci related to the aroma characteristics,and to offer the theoretical and technical support for accurate breeding and further analysis of aroma regulation mechanism,this study used 268 grape germplasms as experiment materials to analyze the characteristic differences of fruit aroma.Combining with genome-wide association analysis,we fund some candidate genes associated with the volatile aroma in grape berry and related SNP loci.The main results are as follows:A total of 66 aromas were identified from 268 grape germplasm resources.They were divided into six categories:esters,terpenoids,alcohols,aldehydes,ketones,and six carbon（C₆）compounds.Among them,C₆ compound is the dominant volatile aroma and the important background material in grape fruit.In addition,esters and terpenoids also showed a relatively high content in grape germplasms,while alcohols,aldehydes and ketones is relatively low in content.And except for ketones,results showed significant distributional differences in other aromas in different grape genotypes.As revealed in the result of aromas proportion,there are dominant C₆ compound（>95%）and few other aromas in hybrids and wild species of grape.While except for aboundant C₆ compounds（80.0%）,there are still a certain of esters and terpenoids（>5%）in V.vinifera and Hybrids between V.vinifera×V.labrusca.In addition,table and wine grapes in these two genotypes showed differences in aroma proportion.Table grapes generally showed a higher terpenoids and a lower esters than wine grapes.And it’s worth mentioning that C₆ compound is not the dominant aroma in‘97-3-45’and‘cabernet sauvignon’,but terpenoids and esters respectively.Thus these germplasms are important research sources for grape bleeding.PCA results showed that different with V.vinifera and Hybrids between V.vinifera×V.labrusca,hybrids and wild species of grape conatined aboundant C₆compound,and is the important resources for the study of uniquely-flavored grapes.And table grape is associated with some terpenoids contributing to rose fragrance,such as linalool,nerol,geraniol,etc.This revealed that table grape is the important resources for studying grapes with muscat aroma.And table grape of hybrid between V.vinifera×V.labrusca is associated with 27 esters.Among them,ethyl caproate and ethyl butyrate was reported as strawberry fragrance volatiles.This displayed that table grapes of hybrid between V.vinifera×V.labrusca is the important resource for trawberry scent research.Associating the volatile aroma results of 268 grape germplasms and the whole genome sequencing results,volatile aroma components in grape berry,including esters,aldehydes,ketones,alcohols,terpenoids,C₆ compounds,were found closely related to 124 candidate genes and 132 SNP loci.The fuction of these genes include the key enzymes in the biosynthetic routes for fatty acid degradation of volatiles in fruits,sugar and glycolipid transport genes,and some domain genes,protein kinases,phosphatases,and some ones with unknown function,etc.