Molecular Diagnosis and Genetic Diversity of Tomato Yellow Leaf Curl Virus in Basra Governorate

Abstract

Abstract This study was conducted to determine the extent of the spread of the Tomato yellow leaf curl in the farms of Basra Governorate. Additionally, the study aimed to detect the genetic diversity of the coat protein CP(V1) of the virus. A total of 137 samples of leaves and stems of the tomato plant were collected from the fields located in the district of Zubair, Al-Burjisiya, Safwan, Khor Al-Zubair and Al-Lahis, Total DNA extraction was performed using the CTAB method and a primer pair; V1 (CP) Forward (EcoRI) and V1 (CP) Reverse (EcoRI), to detect TYLCV. The virus was detected in 84 out of the 137 samples (61.3%), indicating its widespread presence across all surveyed areas. The infection rate ranged from 80.55% to 29% in the districts of Al-Zubair and Khor Al-Zubair, respectively. Analysis of nucleotide sequences revealed that all the obtained sequences corresponded to TYLCV when compared with the equivalent sequences in the NCBI GenBank. The highest nucleotide similarity was observed with the M3 isolate (PP19939), exhibiting 99.31% similarity to the Iraqi isolate (JQ354991). Conversely, the M5 isolate (PP199397) showed the lowest nucleotide resemblance, with 95.30% similarity to the Iraqi isolate (MF429946). Sequencing analysis and the construction of a phylogenetic tree indicated a discrepancy among the studied isolates, with similarity rates ranging from 93% to 98%.