First Report of Seville Root-Knot Nematode, <i>Meloidogyne hispanica</i> (Nematoda: Meloidogynidae), on Tomato and Pepper in Turkiye

With an annual vegetable production of 28.6 million tons, Turkiye ranks fourth globally; 86% is grown in open fields, while 14% is produced under greenhouse conditions (Tatar and Pirinç 2017). Between 2020 and 2022, as part of a field study conducted in the Aegean Region of Turkiye, root samples exhibiting enormous galling symptoms on tomato and vast numbers of egg masses in pepper, caused by root-knot nematodes, were collected from greenhouse production areas: tomato and pepper roots in Balikesir (39°41'13.3"N, 27°56'19.4"E), Usak (38°47'17.3"N, 29°46'26.0"E) and Mugla (36º20ʹ04.1ʹʹN, 29º14ʹ25.4ʹʹE). Nematode females were taken from each root sample for identification via perineal pattern morphometrics (Hirschmann 1986). The perineal patterns were oval-shaped to rectangular, with a low dorsal arch. Dorsal striae exhibit variability, ranging from fine and undulating to coarse lines. The ventral area exhibited lateral wing formations composed of smooth, thin striae. The lateral lines were distinctly forked and widely spaced, with fringe-like striae between them. The tail terminus was well-defined and devoid of striae. The perivulvar region lacked striae, with occasional short lines near the lateral edges of the vulva (Hirschmann 1986). Morphometric measurements of second-stage nematode juveniles obtained from each root sample were fixed, permanent slides were prepared using paraffin wax (Hooper 1986), and morphometric measurements were performed on 20 juveniles. Measurements aligned with Hirschmann (1986) and Maleita et al. (2012), indicating consistency with M. hispanica reference values. Furthermore, DNA extracted from single-egg mass isolates of each population [(Usak (pepper), Balikesir (pepper), and Mugla (tomato)] was amplified using polymerase chain reaction with D2a/D3b primers (D2a: 5’-ACAAGTACCGTGAGGGAAAGT-3’; D3b: 5’-TGCGAAGGAACCAGCTACTA-3’) (Nunn 1992) to target the 28S rDNA gene region (Ye et al. 2015). Following sequence analyses using heterologous primer sequences, nucleotide and amino acid similarity ratios were compared with other registered isolates in the NCBI (National Center for Biotechnology Information) nucleotide database. The nematode populations from Usak (pepper), Balikesir (pepper), and Mugla (tomato), corresponding to GenBank accession numbers PV341209, PV341210, and PV341211, respectively, exhibited sequence similarities of 98.75%, 99.59%, and 99.47% to the reference sequence OQ843182 of Meloidogyne hispanica. These high similarity percentages confirm the identification of the isolates as M. hispanica. Host suitability was tested using five inoculated and five control plants each of tomato (cv. SC2121) and pepper (cv. California Wonder), grown in sterilized soil (70% sand, 30% loam) and inoculated with 1,000 J2s. After 60 days in controlled conditions (23 ± 2 °C, 60 ± 10% RH, 16 h light), gall index (GI) and reproduction factor (Rf) were evaluated. GI/Rf values were: Balikesir (pepper) 4.8/1.85, Mugla (tomato) 4.4/1.5, and Usak (pepper) 3.8/1.06. This study reports the first detection of Meloidogyne hispanica in greenhouse vegetable production areas in Turkiye. This finding highlights the need for comprehensive surveys to determine its distribution and prevalence in other agricultural regions in Turkiye. Understanding its spread is essential for developing effective management strategies to lessen potential impacts on crop yields.