The effects of exogenous methyl jasmonate on FaNES1 gene expression and the biosynthesis of volatile terpenes in strawberry (Fragaria x ananassa Duch.) fruit.

摘要

The volatile terpenoid profiles of cultivated strawberry (Fragaria x ananassa Duch.) fruit are dominated by the monoterpene, linalool, and the sesquiterpene, nerolidol. These terpenoids, generated by the product of the F. x ananassa nerolidol synthase1 (FaNES1) gene, are important for the aroma of strawberry fruit. FaNES1 gene transcript levels and emissions of linalool and nerolidol were measured at various developmental stages in two strawberry cultivars ('Yan Xiang' and 'Shu Xiang'). Up-regulation of FaNES1 gene expression increased the emission of both terpenoids, depending on the degree of fruit ripeness. Terpenoid emissions were highest in red-mature (R) fruit. In addition, exogenous application of methyl jasmonate (MeJA) resulted in cultivar-dependent changes in the level of FaNES1 gene expression and terpenoid emissions. 'Yan Xiang' was sensitive to high concentrations of MeJA (i.e., 10.0 or 100.0 micro M), while 'Shu Xiang' responded to low MeJA concentrations (1.0 micro M). These results suggest that there might be a positive relationship between the emission of volatile aroma terpenoids and levels of FaNES1 gene transcripts. Furthermore, the effect of MeJA on increasing the emission of volatiles might be mediated by the induction of FaNES1 gene expression.