| Research

Study reveals how nematode parasitizes roots of various plants.

The analysis revealed 16 chromosomes with unusual characteristics.

21.11.2025 | 09:40 (UTC -3)

Cultivar Magazine

infecting bean roots; the red-stained structures are female nematodes - Photo: Pallavi Shakya — *Meloidogyne hapla* Infecting bean roots; the red-stained structures are female nematodes - Photo: Pallavi Shakya

Researchers at the University of California, Davis (UC Davis) led a study that deciphered the genome of the northern root-knot nematode with unprecedented precision.Meloidogyne haplaThe team discovered how the genetic structure of this organism allows it to infect a wide variety of plants.

The research resulted in the most complete assembly ever made of the genome of a plant-parasitic nematode. The study used advanced sequencing technologies such as PacBio HiFi, Nanopore, Illumina, and Hi-C. The analysis revealed 16 chromosomes with unusual characteristics. In place of typical telomeres, scientists identified repetitions of 16 nucleotides at the ends of the chromosomes, suggesting an alternative mechanism for protecting the genetic material.

Genetic recombination

The researchers also identified regions with a very high rate of genetic recombination. These zones coincide with genes that encode secreted proteins, known as effectors. These genes help the nematode manipulate the defenses of the host plant. The concentration of these proteins in regions of intense recombination suggests that the parasite exploits this mechanism to diversify its infectious strategies and adapt to different plants.

female (red structure) infecting bean roots - Photo: Pallavi Shakya — *Meloidogyne hapla* Female (red structure) infecting bean roots - Photo: Pallavi Shakya

The structure of the genome of M.hapla The study revealed variations among different lineages of the nematode. Scientists observed chromosomal fusions and breaks that influence reproductive behavior and infectivity. These differences may explain why certain variants of the species attack specific crops, while others affect a wider range of plants.

Genome plasticity

The research also showed that effector genes are absent from regions with low recombination, where conserved genes are concentrated. This reinforces the idea that genome plasticity is crucial for the success of parasitism. According to the authors, genetic mapping can help in the development of more resistant plants and in more effective control of nematodes.

Professor Valerie Williamson, co-author of the study, stated that advances in biotechnology were essential to overcome long-standing challenges, such as the nematode's small size and the complexity of its DNA. The new genetic map will serve as a basis for studying other species of root-knot nematodes and identifying genes essential for parasitism.

Further information can be found at doi.org/10.1371/journal.ppat.1013706