Pyramiding strategy for durable resistance to root-knot nematodes in Prunus Rootstocks

Prunus project

Root-knot nematodes (RKN) (Meloidogyne spp.) are extremely polyphagous pests with a high economic impact at the global scale. In stone fruit trees, three major dominant resistance (R) genes, Ma (plum),RMia (peach) and RMja (almond), have been identified and mapped in this objective. Pyramiding all three R genes opens the way to breeding rootstocks protected by at least two of them for a durable resistance. The Ma gene has been characterized and cloned from a BAC and genetic markers have been developed for using in SAM.  After high-resolution mapping, the two other genes, RMia (peach) and RMja (almond) have been located and mapped on the peach genome, but their sequences were partially aligned on the peach genome.

The objective of the project is to construct 2 BAC libraries from the resistant parents Alnem almond and Nemared peach, to screen two new BAC clones, including each gene and to sequence the BAC clones on the PacBio RSII sequencer.  With the complete sequences of the Rmja and RMia clusters, it will be possible to apply a functional validation by the hairy-roots techniques and to develop new genetic markers for the SAM. New three ways hybrids ((peach x almond) x plum) have been created and it will be possible to select those with two or three R genes. 

It will be possible also to study the polymorphism in the gene and in the regulatory region of the genes, between diploid Prunus species, plum, almond and peach.

Project coordinator:

 Henri Duval
Domaine St Maurice, CS 60094
 84143 Montfavet Cedex, France
 Email :
Phone : 33 4 32 72 26 67


Project partners:

INRA, UMR ‘Institut Sophia Agrobiotech’ (ISA), F-06903 Sophia Antipolis, France
Cyril Van Ghelder, Simon Saucet, Daniel Esmenjaud

CEP Innovation , 69364 LYON

CNRGV involvement:

Responsible: Caroline Callot
 BAC libraries construction - Screening


Duval, H., Hoerter, M., Polidori, J., Confolent, C., Masse, M., Moretti, A., Van Ghelder, C. and Esmenjaud, D. 2014. High resolution mapping of the RMia gene for resistance to root-knot nematodes in peach. Tree Genetics and Genomes 10 (2): 297-306.

Saucet SB, Van Ghelder C, Abad P, Duval H, Esmenjaud D. Resistance to root-knot nematodes Meloidogyne spp. in woody plants. New Phytol. 2016 Jul;211(1):41-56.