First report of Citrus bent leaf viroid in the United Arab Emirates.
Leaf samples were collected from four lemon (Citrus limon) and five sweet orange (C. sinensis) groves located in Al-Ain (south east of Abu Dhabi, UAE). Sampled trees showed weakened growth, but typical symptoms of viroids were not detected. The samples were tested for the presence of viroids by multiplex RT-PCR using two sets of primers specific for Citrus exocortis viroid (CEVd) and Citrus bent leaf viroid (CBLVd). Testing disclosed the association of CEVd with 15 of 16 lemons in four groves, and with 18 of 18 sweet oranges in five groves. CBLVd was detected in six of 16 lemons in three groves and in five of 18 sweet oranges in three groves. CEVd sequences from the UAE were identical to each other and shared 99% nucleotide similarity to CEVd isolate CEVd-XNM-XY (GenBank accession No. DQ431993), while the CBLVd sequence was identical to that of CBLVd isolate 201-1-2 Uy (accession No. AF428053). This is thought to be the first record of CBLVd in the UAE.