INCIDENCE AND DISTRIBUTION OF FIG BADNAVIRUS 1 AND MULBERRY BADNAVIRUS 1 ON MULBERRY TREES IN IRAN

Abstract

Fig badnavirus 1 (FBV-1) and mulberry badnavirus-1 (MBV-1) are two closely related badnaviruses which were recently identified in fig and mulberry plants. Thirty-six fig and 27 mulberry orchards were surveyed to determine the presence and incidence of FBV-1 and MBV-1 in four provinces of Iran. A total of 81 fig and 70 mulberry asymptomatic and symptomatic leaf samples were collected in April to August 2015 and tested by PCR. Approximately 62% and 33% of the tested fig and mulberry samples, respectively, were infected with FBV-1. None of the fig samples was found to be infected with MBV-1. MBV-1 was detected in only 8.5% of the mulberry samples collected in two provinces. Mixed infections of FBV-1 with MBV-1 were detected in 7% of the samples. The presence of both viruses in asymptomatic and symptomatic trees was verified by PCR. Sequence analysis of the cloned movement protein (MP) gene of thirteen Iranian FBV-1 isolates showed 97-99% nucleotide (nt) sequence identity among the isolates and 98-99% nt sequence identity to the American reference isolate. The MP fragments of two Iranian MBV-1 isolates showed 98-100% nt sequence identity to the reference Lebanese MBV-1 isolate. In phylogenetic analyses, isolates of FBV-1 formed two distinct clades and grouped according to the host. To our knowledge, this is the first report of FBV-1 and MBV-1 infecting mulberry plants in Iran.