Identification and expression analysis of furanocoumarins- and terpenoids-related genes of fig (Ficus carica L.)

The fig tree is a species particularly rich in volatile organic compounds, the production of which is becoming increasingly important for pharmaceutical purposes. This work was aimed at isolating genes related to the biosynthesis of furanocoumarins (especially psoralen) and terpenoids in the leaves of fig. Using gene sequences identified in other species, we performed an analysis of sequence similarity in the fig transcriptome and retrieved 49 genes, 13 related to the biosynthesis of furanocoumarins and 36 to that of terpenoids. The expression of these genes was studied by RNA-seq analysis in leaves of control and salt-treated plants. Most genes resulted regulated after salt treatment. Psoralen and terpenoids in the leaves were quantified by solid phase microextraction, and their concentration resulted correlated to the expression of genes putatively involved in their biosynthesis. These results will be useful for future breeding strategies to increase the production of fig volatile organic compounds.