First report of Meloidogyne incognita infecting Epimedium sagittatum in Guizhou Province, China

Abstract

Epimedium sagittatum (Sieb. et Zucc.) Maxim., an important member of the Berberidaceae family, serves as a critical source for traditional Chinese medicines. With the expansion of its cultivation area, various diseases have emerged, leading to significant production losses. During recent field surveys of E. sagittatum in Guizhou Province, root galls characteristic of Meloidogyne spp. infection were observed. The root-knot nematodes were isolated and identified based on the morphological characteristics of females and second-stage juveniles (J2s). Molecular analyses, including sequencing of the internal transcribed spacer (ITS) region of rRNA, the D2-D3 region of 28S rRNA, and the mitochondrial cytochrome oxidase subunit I (mtCOI) gene, were conducted. The pathogen was conclusively identified as Meloidogyne incognita. Pathogenicity tests under greenhouse conditions, in which E. sagittatum plants were inoculated with M. incognita, reproduced symptoms identical to those observed in naturally infected field plants. The nematodes were successfully re-isolated from diseased roots and confirmed as M. incognita through morphological and molecular characterization, thereby fulfilling Koch's postulates. This report represents the first documented case of M. incognita infecting a plant from the Berberidaceae family, with E. sagittatum identified as a novel host. This discovery extends the known host range of the destructive plant-parasitic nematode M. incognita to the Berberidaceae family. Therefore, its presence in E. sagittatum needs close surveillance, especially in key cultivation regions.