Interactions of root-knot, root-lesion and cyst nematodes with legumes and implications for plant-breeding

Legumes play a pivotal role in global food security, supporting symbiotic nitrogen fixation and sustainable cropping systems, yet their productivity is increasingly constrained by plant-parasitic nematodes. This review synthesises current knowledge of the three major nematode groups affecting legume crops: root-knot nematodes ( Meloidogyne spp.), cyst nematodes ( Heterodera spp.), and root-lesion nematodes ( Pratylenchus spp.). Particular emphasis is placed on their parasitic strategies, host interactions, and implications for plant protection, with plant breeding considered the main sustainable management tool. We examine how the sedentary endoparasites, root-knot and cyst nematodes, establish specialised feeding structures, namely giant cells and syncytia, respectively, which reprogramme host development and interfere with legume-rhizobia symbiosis. Through complex hormonal and molecular crosstalk, these pathogens interfere with nodulation and biological nitrogen fixation. In contrast, migratory root-lesion nematodes cause chronic mechanical damage without establishing permanent feeding sites. Pre- and post-infection resistance mechanisms are reviewed, including structural barriers, chemical deterrents, hypersensitive responses, and hormone-mediated defence pathways. These are discussed alongside characterised resistance loci, including rhg1/Rhg4 in soybean, CRE1 in chickpea and the Rk locus in cowpea. We further review breeding strategies ranging from conventional phenotypic selection and marker-assisted breeding to genomic selection, CRISPR-based genome editing, and high-throughput phenotyping. Emerging approaches that integrate host genetics with rhizosphere-microbiome management to enhance resistance durability are also considered. Despite significant advances in well-studied pathosystems, particularly the soybean-soybean cyst nematode interaction, understanding of most legume-nematode interactions remains limited. Knowledge gaps are especially pronounced in minor and winter legume crops, for which breeding often represents the most practical and sustainable management strategy. Future progress will require multidisciplinary approaches that integrate molecular biology, genomics and agroecology to develop durable nematode resistance and support sustainable legume production.