Dynamic Changes Of 2-phenylethanol Content And Its Effect Under Agronomic Regulation In Vidal Grape And Its Bud Sport

Grape aroma is an important component of fruit quality,and 2-phenylethanol is a typical aroma substance,so it is of great significance to study.In this study,wine grape Vidal and its bud sport were used as the material.Different changes of 2-phenylethanol and VvAADC were investigated by dynamic measurement and regulation.Systematic and comprehensive evaluation has been done for Vidal grape.The dynamic changes of the content and the synthesis of the special aroma 2-phenylethanol in Vidal grape was uncovered,laying a foundation of 2-phenylethanol regulation mechanism.1.There are differences between Vidal grape and its bud sport in phenotype,changes of 2-phenylethanol and its synthesis.The mutant had shorter stems,larger cluster,higher single berry weitht,higher soluble solids,lower total acid and weaker growth.In different phenological stages,2-phenylethanol content showed an increase-decrease-increase changing pattern.At 180 days after flowering(freezing harvest time),the 2-phenylethanol content reached the top,being 0.412 mg/kg,significantly higher than that in fruit(0.392 mg/kg).Phenethylamine content showed an increase-decrease changing pattern.At 130 days after flowering,phenethylamine content reached the top.Benzene acetaldehyde content showed an increase-decrease changing pattern.At 110 days after flowering,phenethylamine content reached the top,and then sharply dropped.2.For the relative expression of VvAADC gene,differences could be observed between Vidal grape and its bud sport.There were three expression peaks during the development of Vidal grape berry,being 50,95 and 140 days after flowering,but the mutant only had two gene expression peaks,being 80 and 140 days after flowering.There were significant differences of VvAADC expression between Vidal grape and its bud sport.Gene expression peak appeared after veraison in both materials.Campared with Vidal grape,the expression level of VvAADC gene was higher in its bud sport.3.Compared with the Vitis Vinifera reference genome,the resequencing of Vidal and its bud sport generated 1701990 and 1690044 SNPs respectively.The number of CDS-Insertion was 7793,7662 and 8273 in Vidal,Vidal mutants and the sum of both respectively.The number of CDS-Deletion was 9176,9082 and 9669 in Vidal,Vidal mutants and the sum of both respectively.Important GO annotation of Vidal grape include Cellular Component: vacuolar membrane(GO: 0005774),Molecular Function: heat shock protein binding(GO: 0031072)and Biological Process: proline transport(GO: 0015824).4.Heavy crop load led to low content of 2 – phenylethanol,as well as low content of glucose,fructose and total sugar and high content of tartaric,malic and total acid,resulting in a low sugar/acid ratio.It can be found through crop load treatment that lower crop load led to a high expression of VvAADC gene at early development stage and low expression of VvAADC gene at late development stage,and vice versa.5.N fertilizer had little effect on the increasing of 2-phenylethanol content in Vidal grape,but P fertilizer had a strong effect,and K fertilizer had the strongest effect.The expression of VvAADC gene exhibited significant differences under different fertilization treatments.