Yüzüncü Yıl Üniversitesi Tarım Bilimleri Dergisi

Phytoplasmas are dangerous bacteria severely infecting agricultural production worldwide. In the present study, the identification of phytoplasmas infecting tomato plants showing symptoms such as small leaves, flower abnormalities, stunting, witches' broom, and reddening was performed. Five plants, two symptomatic and three asymptomatic, were tested to verify phytoplasma infection. Total DNA isolated from 5 leaf samples was used as a template for PCR reactions. The phytoplasma agents were confirmed in the two symptomatic samples. BLASTn search of 16S rRNA of two sequences shared identity similarity of 99.84% with ‘Candidatus Phytoplasma australasia’. Computer-simulated virtual RFLP profiles show that the 16S rRNA sequences is identical to the reference pattern of the 16SrII-D subgroup, with a similarity coefficient of 1.00. Based on BLAST, virtual RFLP, and phylogenetic dendrogram, the identified phytoplasma strains are enclosed in the 16SrII-D subgroup. This is the first report of tomato witches' broom disease related to 16SrII-D subgroup phytoplasma strains in the Antalya province of Türkiye.

Tomato (Solanum lycopersicum) is one of the most financially important vegetable crops. It is a species belonging to the Solanaceae family and is cultivated in many countries, including Turkey. The natural presence of ‘Candidatus Phytoplasma solani’ (‘Ca. P. solani’) from the Stolbur group (16SrXII) in tomato plants is extensively characterized based on the 16S rRNA gene worldwide. Tomato plants displaying abnormality and sterility of flower, purpling, and bushy appearance were observed in the Van province, Turkey. DNA extraction from tomato leaves was performed, and the extracted DNA was used to amplify 16S rRNA sequences using universal primer pairs by double PCR assays. After confirming the presence of the probable agent (‘Ca. P. solani’), nested PCR testing was performed using an appropriate primer set amplifying the SecY and Vmp1 genes of the same DNAs. Amplified PCR yields were then cloned into a pGEM T-Easy vector and sequenced by New Generation System (NGS). Sequenced 1438 bp nucleotides for Vmp1 gene (MN104838) and 905 bp nucleotides for SecY gene (MN125054) revealed 97.38% and 100% maximum nucleotide similarity with formerly published Vmp1 and SecY gene sequences of ‘Ca. P. solani’ species belonged to the Stolbur group (16Sr-XII), respectively. According to the phylogenetic tree created using our gene sequences from ‘Ca. P. solani’, Vmp1, and SecY gene sequences showed a highly phylogenetic affinity with the same sequences of the same agent from Serbia and France, respectively. To the best of our knowledge, this study is the first report to reveal the phylogenetic relationships of ‘Ca. P. solani’ in stolbur group (16Sr XII-A) using SecY and Vmp1 genes in the tomato plant in Turkey based on the non-ribosomal genes.