Новая цистообразующая нематода Globodera chizhovi sp. n. (Tylenchida: Heteroderidae), с молекулярной характеристикой двух видов этого рода из Мексики

In autumn 2024, during nematological surveys of solanaceous plants in several states of Mexico, an unknown Globodera species named here as G. chizhovi sp. n., the golden potato cyst nematode G. rostochiensis and the Mexican cyst nematode G. mexicana were found in soil and root samples. Cysts of Globodera chizhovi sp. n. were collected from roots of a wild sage Salvia polystachia (family Lamiaceae) growing in a forest in Ozumba municipality, Mexico State. The new species was characterised by small cyst size (L=220-470 µm), small Granek ratio (0.3-2.3) and number of cuticular ridges between vulva and anus ranged from 3 to 9. The second-stage juvenile of the new species was 350-580 µm in length with stylet 20-24 μm long. Globodera rostochiensis was found from potato fields and wild potato plants, Solanum demissum, growing at the edge of these fields in Mexico State. Globodera mexicana was collected from roots of the pubescent nightshade S. pubigerum. New ten D2-D3 of 28S rRNA, six ITS rRNA, fourteen COI and twelve cytb gene sequences from seven samples of three species were obtained in this study. The gene sequences clearly differentiated G. chizhovi sp. n. from all other Globodera species. Phylogenetic relationships of G. chizhovi sp. n., G. rostochiensis and G. mexicana from Mexico with other Globodera species and some representatives of the subfamily Punctoderinae were given based on the analysis of four gene sequences. In the ITS rRNA gene tree, sequences of G. chizhovi sp. n. showed a sister relationship with those of the Globodera clade parasitising solanaceous plants. It has been suggested that the Sierra Madre Mountains could be considered as one of the centres of diversity and origin for the genus Globodera. Mexican Globodera rostochiensis COI and cytb sequences were assigned to GrCOIA1 and GrCbA1 haplotypes, respectively.