Partial biological and molecular characterization of various tospoviruses from Markazi province

Members of the genus Orthotospovirus cause serious diseases in a variety of economically important crops, including ornamentals and vegetables, worldwide. To detect the orthotospoviruses infecting different crops and ornamental plants in Markazi province, Iran, about 160 suspected samples with viral-like symptoms were collected. Totally 106 of the specimens showed positive reaction in DAS-LEISA test using polyclonal antibodies raised against N proteins of Tomato yellow ring virus (TYRV), Iris yellow spot virus (IYSV) and Groundnut bud necrosis virus (GBNV). Sequence analysis of the obtained fragments from RT-PCR using generic primers of Asian and Eurasian clades of tospoviruses and nucleocapsid gene specific primers confirmed the occurrence of TYRV on alstroemeria, tobacco, tomato and nasturtium; IYSV on onion and leek and Capsicum chlorosis virus (CaCV) on black-eyed susan (Rudbeckia sp.). Biological analysis of selected isolates of orthotospoviruses on Nicotiana benthamiana, Capsicum annuum and Vigna unguiculata showed that TYRV isolates were differentiated from each other. Phylogenetic analysis based on amino acid sequences of nucleocapsid protein indicated that TYRV isolates belong to TYRV-t strain and IYSV isolates belong to Eurasia-IYSV cluster. In addition, CaCV isolates were grouped into Watermelon silver mottle virus (WSMoV) clade with close relationship with the United State CaCV isolate.