First report of tomato spotted wilt virus on Iris domestica in South Korea

In May 2020, necrosis and necrotic ring patterns were observed on leaves of three of 140 Iris domestica plants in a demonstration garden in Wanju, Jeollabuk-do. Three symptomatic plants were found to be infected by tomato spotted wilt virus (TSWV). To analyze the whole genomic sequence of one TSWV isolate,’Blackberry lilykr1’, L, M, and S genome segments were sequenced and analyzed by comparison of nucleotide sequences of the three segments with corresponding sequences of other TSWV isolates. ‘Blackberry lily-kr1’ isolate was most closely related to ‘JJ’ isolate (MF159046) or ‘HJ’ isolate (LC273305) in the L segment, and to ‘JJ’ isolate (MF159058 and KY021439) in the M and S segments, respectively. Phylogenetic analysis by Maximum likelihood method using MEGA X program with ‘Blackberry lily-kr1’ isolate showed high relationship with ‘JJ’ pepper isolate or ‘HJ’ Humulus japonicas isolate in the all three segment. Necrosis and double ring patterns on leaves were formed in the glasshouse after inoculation of healthy I. domestica plants with sap of ‘Blackberry lily-kr1’-infected Nicotiana rustica plants. This result suggests that I. domestica plants showing necrotic ring patterns in the open field are caused by TSWV infection. This is the first report of TSWV infection of I. domestica in Korea.