Figure 3: Phylogenetic tree of the P19 genes Egh, compared to that of P19 and P22 genes of reported TBSV isolates. A: the phylogeny based on the DNA nucleotide sequence. B: Deduced amino acids sequence alignment between the four obtained P19 genes and other P19 genes of tomato, lettuce, and silencing genes. C: Sequence alignment between the four P19 genes amplified from pure TBSV and from the three inoculated tomato cultivars by the use of ClustalW 1.4.