The Northern Root-Knot Nematode Meloidogyne hapla: New Host Records in Portugal

Abstract

Root-knot nematodes (RKNs), Meloidogyne spp., are a group of plant-parasitic nematodes (PPNs) of great economic significance worldwide. The northern root-knot nematode, Meloidogyne hapla, is one of the most important species of RKNs occurring in cold regions. In Portugal so far, M. hapla has been found parasitizing potato and fig trees. During surveys carried out in 2019–2022 in fields for horticultural and ornamental production, soil and root samples were collected. Roots were observed under a stereomicroscope to determine the presence of galls. Nematodes were extracted from the soil. Morphological features showed a high similarity and consistency with previous descriptions of the genus. For molecular analysis, total genomic DNA was isolated from single nematodes and used to amplify in multiplex reaction using the species-specific primers JMV1, JMV2 and JMVhapla, and for sequencing of the ITS region with the primers TW81/AB28. Multiplex PCR amplification produced a specific fragment of 440 bp and PCR amplification of the ITS region yielded a single fragment of 550 bp, as expected. The obtained sequences showed a similarity ranging from 99.8% to 100% with the sequences of M. hapla available in the database. The phylogenetic tree revealed that the isolates grouped with M. hapla isolates. From the 690 samples collected, M. hapla was detected in three different hosts (grapevine, eucalyptus and potato) in four districts of mainland Portugal and on Madeira Island. To our knowledge, this is the first report of M. hapla infecting the grapevine and eucalyptus in Portugal.

Possible mechanisms of action of Bacillus wiedmannii AzBw1, a biocontrol agent of the root-knot nematode, Meloidogyne arenaria

“…Among the well-known species of the Meloidogyne genus, four species, M. incognita, M. javanica, M. arenaria, and M. hapla are the most common and important species (Rusinque et al 2022). They have vast host ranges, as they all infect many common vegetable crops.…”

Study on the effect of electric pulse treatment for disinfestation of vegetables

“…Cultivation of these products is hampered by nematodes that develop on the roots of the plants. Namely, the northern nematode Meloidogyne hapla [11] belonging to the Meloidogyne Goel group, the southern nematode Meloidogyne incagnita, the Javanese nematode Meloidogyne javanica Treual, and the nut nematode Meloidogyne arenaria Neal. Current nematode disease prevention methods include prophylaxis and mass extermination.…”