Occurrence of fig mosaic disease in Tuscany, Central Italy: Characterization of new fig mosaic virus isolates, and elucidation of physiochemical responses of infected common fig cv. Dottato

Fig mosaic disease (FMD) is a major disease affecting fig trees, for which only fig mosaic virus (FMV) has been identified as etiological agent. In the present study, trees of common fig cv. Dottato, belonging to the old Tuscan germplasm, were investigated to pioneering (i) evaluate the presence of FMV in Tuscany (Central Italy), as well as other FMD-associated viruses previously reported in Italy, (ii) type and phylogenetically characterize the reported FMV isolates, and (iii) elucidate some physiological and biochemical responses of fig trees challenged by FMV. Although many studies on FMD have been carried out in Southern Italy, the present study represents the first identification of the disease in another Italian area. This work (i) showed that FMD is present also in Central Italy, also suggesting a wider diffusion than what has been reported so far; (ii) confirmed that the disease is caused by FMV, tested positive in both symptomatic and asymptomatic leaves (100 and 27% of tested samples, respectively); and also fig fleck-associated virus (FFKaV) was reported; (iii) identified three new FMV isolates (i. e., Dot-1, Dot-2 and Dot-3, deposited in GenBank), which resulted not close to other FMV Italian isolates; and (iv) pioneering elucidated that FMV impaired photosynthesis and organic acid biosynthesis in symptomatic leaves, but negative effects occurred also in asymptomatic ones in terms of photosynthetic and accessory pigments. More research should be carried out to improve our knowledge on FMD diffusion and FMV (and FFKaV) genetic features, as well on the effects of this regulated non quarantine pest on fig trees, also investigating its fruits representing an ancient source of food and health.