Identification and Expression of the peach TNL RMia genes for the Resistance to the Root-knot Nematode Meloidogyne incognita

Scientia Horticulturae 343, 114081. https://doi.org/10.1016/j.scienta.2025.114081

Root-Knot Nematodes (RKN) are major pests for world agriculture. As RKN are polyphagous endoparasites, present in various climates and able to multiply rapidly, the quest to discover new natural resistances in plants is essential. In Prunus species, several major resistance genes to RKN that belong to the NLR family, have been detected in recent years. In Peach, the RMia gene, which confers resistance to the RKN Meloidogyne incognita, M. arenaria, and M. ethiopica, was localized on the chromosome 2. In this study, we used short- and long-read sequencing technologies to identify the RMia gene in two independent RKN-resistant peach varieties, 'Nemared' and 'Weeping Flower peach' . We characterized three candidate genes (RMiaGC1, RMiaGC2, RMiaGC3) and studied their expression profile upon RKN infection. Our study identified and characterized these candidates that are most likely involved in the RKN resistance and showed that the RMiaGC1 gene is the most highly expressed in resistance. Finally, we have developed new molecular markers associated with this resistance that can be used for marker-assisted selection in Prunus rootstock breeding programs (Cf Figure 1)

Figure 1: Genotyping using molecular markers designed in the RMia region for resistant and susceptible peaches.  (a) Position of the framing markers SNP092 and SP091 and specific markers b) DNA amplifications for the RMiaGC1 and RMiaGC2 genes with the primers G13F1R1, G13QP211 and G31F5R5, respectively