title: The Ma gene for complete-spectrum resistance to Meloidogyne species in Prunus is a TNL with a huge repeated C-terminal post-LRR region.
abstract: Root-knot nematode (RKN) Meloidogyne species are major polyphagous pests of most crops worldwide, and cultivars with durable resistance are urgently needed because of nematicide bans. The Ma gene from the Myrobalan plum (Prunus cerasifera) confers complete-spectrum, heat-stable, and high-level resistance to RKN, which is remarkable in comparison with the Mi-1 gene from tomato (Solanum lycopersicum), the sole RKN resistance gene cloned. We report here the positional cloning and the functional validation of the Ma locus present at the heterozygous state in the P.2175 accession. High-resolution mapping totaling over 3,000 segregants reduced the Ma locus interval to a 32-kb cluster of three Toll/Interleukin1 Receptor-Nucleotide Binding Site-Leucine-Rich Repeat (LRR) genes (TNL1-TNL3), including a pseudogene (TNL2) and a truncated gene (TNL3). The sole complete gene in this interval (TNL1) was validated as Ma, as it conferred the same complete-spectrum and high-level resistance (as in P.2175) using its genomic sequence and native promoter region in Agrobacterium rhizogenes-transformed hairy roots and composite plants. The full-length cDNA (2,048 amino acids) of Ma is the longest of all Resistance genes cloned to date. Its TNL structure is completed by a huge post-LRR (PL) sequence (1,088 amino acids) comprising five repeated carboxyl-terminal PL exons with two conserved motifs. The amino-terminal region (213 amino acids) of the LRR exon is conserved between alleles and contrasts with the high interallelic polymorphisms of its distal region (111 amino acids) and of PL domains. The Ma gene highlights the importance of these uncharacterized PL domains, which may be involved in pathogen recognition through the decoy hypothesis or in nuclear signaling.
authors.affiliation: INRA, UMR Interactions Biotiques et Santé Végétale INRA 1301, CNRS, UMR CNRS 6243, and Université de Nice Sophia-Antipolis, F-06903 Sophia-Antipolis, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Claverie
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Dirlewanger
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bosselut
authors.forename: Cyril
authors.initials: C
authors.lastname: Van Ghelder
authors.forename: Roger
authors.initials: R
authors.lastname: Voisin
authors.forename: Marc
authors.initials: M
authors.lastname: Kleinhentz
authors.forename: Bernard
authors.initials: B
authors.lastname: Lafargue
authors.forename: Pierre
authors.initials: P
authors.lastname: Abad
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Rosso
authors.forename: Boulos
authors.initials: B
authors.lastname: Chalhoub
authors.forename: Daniel
authors.initials: D
authors.lastname: Esmenjaud
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D005091:Exons / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics*; D056726:Genetic Association Studies; D005816:Genetic Complementation Test; D056426:Genetic Loci / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics*; D007438:Introns / Q000235:genetics; D000090263:Leucine-Rich Repeat Proteins; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D020161:Physical Chromosome Mapping; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000469:parasitology; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000276:immunology / Q000469:parasitology; D011401:Promoter Regions, Genetic / Q000235:genetics; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D027861:Prunus / Q000235:genetics* / Q000276:immunology / Q000469:parasitology*; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics; D015203:Reproducibility of Results; D013045:Species Specificity; D014431:Tylenchoidea / Q000502:physiology*
chemical_list: D000090263:Leucine-Rich Repeat Proteins; D010940:Plant Proteins; D011506:Proteins