关键词: 森林草莓, 醇酰基转移酶, 遗传转化, 挥发性成分检测, 实时定量PCR

Abstract: FvAATW2 was an alcohol acyltransferase gene，cloned from Fragaria vesca L. fruits by RT-PCR. In this study，the sense plant expression vector pBI121-FvAATW2 driven by cauliflower mosaic virus 35S promoter was constructed through replacing GUS with FvAATW2，and then was used to genetically transform tobacco and a cultivated strawberry cultivar‘Camarosa’，to study the function of FvAATW2. Agrobacterium tumefaciens strain LBA4404 carrying pBI121-FvAATW2 was employed to infect leaf-discs in the genetic transformation. Transgenic lines were identified by both PCR and Southern blot. The expression of exogenous FvAATW2 in transgenic in vitro plants was studied using relative enzyme activity and real-time quantitative PCR. It was found that FvAATW2 expressed in all 6 tested tobacco lines and AAT activity values of 5 lines were higher than wild-type plants. Volatiles in leaves of the transgenic tobacco with the highest AAT activity were also detected by SPME/GC-MS at 10 ~ 12 leaves phase. Octyl propanoate was found in transgenic leaves，while not any ester captured in wild-type plants at the same phase. The results showed that pBI121-FvAATW2 functioned correctly and esters could be synthesized much earlier in transgenic tobacco than in wild-type one. Four strawberry transgenic lines were obtained after PCR and Southern blot operation. A transgenic line bearing more aromatic fruits was screened out and used for the volatiles detection. Through analyzing the ester composition of mature transgenic fruits，it was found that the proportion of esters in total volatiles and respective proportions of octyl acetate，ethyl hexanoate，octyl hexanoate，and ethyl octanoate were higher significantly than those of wild-type fruits，while mass fraction of methyl butanoate decreased significantly and that of ethyl octanoate increased significantly. It was indicated that exogenous FvAATW2 expressed normally in cultivated strawberry and effected ester synthesis，and it could make fruit aroma intense by changing ester composition.

Key words: Fragaria vesca, alcohol acyltransferase, genetic transformation, volatile detection, real-time qPCR