Introduction and molecular characterization of tomato yellow leaf curl virus in Okinawa, Japan

Abstract

Tomato yellow leaf curl disease (TYLCD) caused by Tomato yellow leaf curl virus (TYLCV) has been identified in Okinawa Prefecture, a subtropical region in Japan, for the first time in 2007. Infected tomato plants were collected from Tomigusuku City, Uruma City, Yomitan-son, and Nakijin-son on the main island of Okinawa. The complete nucleotide (nt) sequence of the TYLCV-Israel[Japan:Tomigusuku:2007] (TYLCV-IL[JR:Tom:07]) isolate obtained from Tomigusuku was determined. The sequence comparison with four representative TYLCV isolates in Japan showed that TYLCV-IL[JR:Tom:07] was most closely related to TYLCV-Israel[Japan:Tosa:2005] (TYLCV-IL[JR:Tos:05]), a member of the Israel strain of TYLCV (TYLCV-IL). The phylogenetic relationship analyses were performed based on determined partial nucleotide sequences of approximately 1,400 nt of 14 other isolates collected from 7 distinct locations. All the Okinawa isolates were separated into the cluster including TYLCV-IL[JR:Tos:05] and at least 2 distinct isolates of the TYLCV-IL were introduced onto the main island of Okinawa. These results indicated that the introduction of TYLCV into Okinawa might have been caused by domestic transportation of infected plants.