Serological and Molecular Detection of Viruses Infecting Fig to Identify the Virus-Free Plants

Abstract

Fig (Ficus carica L.) is one of the old and the most common fruit tree grown in all the Mediterranean countries, which is among those exposed to diseases and pathogens. A recent investigation indicated that fig mosaic disease was the main pathogenic agent. In this study, field surveys were conducted in different areas of Egypt. A total of 300 leaf samples were collected randomly from symptomatic and symptomless fig trees of six cultivars, and tested by RT-PCR for the presence of Fig mosaic virus (FMV), Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FMMaV-2), Fig mild mottle-associated virus (FMMaV) and Fig latent virus 1 (FLV-1), using specific sets of primers. About 84% of the samples tested were found to be infected by at least one virus. FLMaV-1 was the prevailing virus with a (78.3%) incidence followed by FMV (73.7%), FLMaV-2 (50%), FLV-1(40.3%) and FMMaV (35%). The highest infection rate was observed in Sultani, Asuani and Adasi-Ahmer (100%), followed by Kahramani (80%), Kadota (64%) and Black Mission (60%).Ultra thin section for infected fig plants showed a large double-membrane particles (DMPs) 100-150 nm in diameter were located in the cytoplasm of parenchyma cells. Fig mosaic virus-specific antiserum raised in rabbits, proved useful for its detection in fig tissues. The plantlets from meristem tip tissue culture were transplanted successfully. FMV could be detected through DAS-ELISA in the virus-free fig plantlets.