Micropropagation of virus-free plants of Saudi fig (Ficus carica L.) and their identification through enzyme-linked immunosorbent assay methods

Viral infection is one of the most serious biotic stresses, which disturbs the growth and productivity of many horticultural crops, including that of fig (Ficus carica L.). The production of plants free of viruses, such as fig mosaic virus (FMV), has become a priority in many plant breeding programs. In this study, leaves from plants of two fig cultivars, Kodato and Dattora, infected with FMV were collected from both Mecca and Al-Taif, Saudi Arabia. Transmission electron microscopy of ultrathin leaf sections showed double membrane bodies, characteristic of FMV particles, only in the mesophyll cells of infected samples. Protein analysis using sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of a protein band with a molecular weight of 35 kDa, which corresponded to the viral coat protein; and FMV was confirmed by Western blot and enzyme-linked immunosorbent assay (ELISA) tests. To obtain virus-free plants, apical shoot culture was applied. A comparison of various artificial media with different concentrations of growth regulators was evaluated to optimize shoot formation, shoot multiplication, and root formation, and was followed by plant acclimation ex vitro. Direct ELISA analysis of shoots micropropagated from meristem tip explants indicated that there were virus-free shoots, when compared to infected plants (positive control), while there were no significant differences between these explants and healthy samples (negative control). This study demonstrated that in vitro micropropagation of Saudi F. carica infected with FMV virus led to the successful elimination of the virus.