Association of tomato yellow leaf curl virus - Oman strain with the leaf curl and yellow mosaic symptoms on papaya and wild poinsettia in Oman

Begomoviruses (Geminiviridae) cause severe diseases in several crops, often causing significant losses due to reduced yield and quality. These viruses are easily transmitted by the whitefly (Bemisia tabaci) vector. Begomovirus-like symptoms were observed in wild poinsettia (Euphorbia cyathophora) and cultivated papaya (Carica papaya) plants in the Nizwa, Al-Dakhliya and Al-Batinah regions of Oman, where papaya is grown extensively. The aim of this study was to identify the suspected viral causal agent associated with yellow mosaic and leaf curl symptoms in the poinsettia and papaya plants. Symptomatic leaf samples were collected and subjected to DNA isolation followed by PCR amplification with begomovirus-coat protein specic primers. An amplicon of betasatellites was also amplified using betasatellite-specific primers. The amplicons were cloned and sequenced bi-directionally. The full-length begomoviral genome was determined to be 2766 and 2752 bp in length for the wild poinsettia and papaya isolates, respectively. The respective betasatellites were found to be 1354 and 1370 bp. Sequence analysis indicated that the papaya isolate, herein tomato yellow leaf curl virus (TYLCV)-Pap-Oman, shared 95.0% nucleotide identity with the wild poinsettia isolate, herein TYLCV-Poin-Oman, followed by 93.5% identity with TYLCV-Iran (GU076448). Phylogenetic analysis grouped TYLCV-Pap-Oman and TYLCV-Poin-Oman with TYLCV isolates previously reported from Iran, Saudi Arabia and Sudan, whereas the two betasatellites grouped them with TYLCB isolates previously reported from Oman. Based on the nucleotide sequence identity and phylogenetic tree analysis, the Begomovirus identified from papaya and wild poinsettia is considered an isolate of TYLCV from plant host species previously reported in the Arabian Peninsula.