DisplayTitle

First Report of the Root-Knot Nematode Meloidogyne ethiopica on Tomato and Cucumber in Turkey

The root-knot nematode Meloidogyne ethiopica Whitehead, mainly reported from African countries, was first described in 1968 in Tanzania (4). It was further detected in South America (Brazil, Chile, and Peru) (2). In 2004, M. ethiopica was recorded for the first time in Europe on tomato (3) and later in field soil samples from maize (Zea mays L.) and kiwi [Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferguson] collected in the area of Kavalla in North Greece (1). M. ethiopica was included on the EPPO alert list of harmful organisms in 2011. In summer 2009, severe stunting, leaf wilting, and extensive root galling of a presumed root-knot nematode (Meloidogyne sp.) were detected during a routine survey for root nematodes attacking tomato (Solanum lycopersicum L.) crops from two greenhouses in the campus of University of Ondokuz Mayis and attacking cucumber (Cucumis sativus L.) crops from commercial greenhouses in Çarsamba district of Samsun Province, Turkey. Perineal patterns of Meloidogyne sp. females collected from infested roots were variable, with moderately high to high dorsal arch, lateral line mostly indistinct and striae usually wavy, which is very similar to that seen in M. incognita Kofoid & White. Such variability among perineal patterns precluded its accurate identification. For further species identification, protein extracted from young egg-laying females were resolved in 3% stacking (pH 6.8) and 7% separating (pH 8.8) polyacrylamide gel with Tris-glycine buffer. The gels were stained with α-naphthyl acetate substrate for esterase activity (1). The esterase phenotypes exhibited a three banded pattern, E3, that was identical to M. ethiopica. Therefore, esterase studies were repeated including nematodes from M. ethiopica culture from Slovenia used as a reference. In addition, small subunit rDNA sequence analyses were performed to complete species identification. DNA sequences of a 1.6-kb rDNA fragment were generated using two sets of primers (1) and deposited in the NCBI GenBank with the accession number KC551945. The sequence was compared to the corresponding fragments of M. ethiopica and closely related species from the NCBI GenBank. DNA sequence of M. ethiopica from Turkey exhibited the highest identity of 99.8% to the sequence FJ559408 of M. ethiopica from Slovenia. Sequences KC551945, FJ559408, AY942630, and JQ768373 of M. ethiopica from Turkey, Slovenia, Brazil, and Greece, respectively, clustered together and formed a separate clade using phylogenetic analyses. This species may pose a threat for vegetable production in Turkey since it has a wide host range infesting numerous higher plants including monocotyledons, dicotyledons, herbaceous, and woody plants. Furthermore, M. ethiopica may have been present in Turkey for many years because correct identification based only on perineal pattern is difficult. Thus, misidentification might have been possible. The distribution of this nematode in more extensive vegetable fields should be determined. To our knowledge, this is the first report of M. ethiopica in Turkey and the third finding of this species in Europe.

References: (1) I. L. Conceição et al. Eur. J. Plant Pathol. 134:451, 2012. (2) S. N. Murga-Gutierrez et al. Nematropica. 42:57, 2012. (3) S. Širca et al. Plant Disease. 88:680, 2004. (4) A. G. Whitehead. Nematology. 15:315, 1969.