The heat-stable root-knot nematode resistance gene Mi-9 from Lycopersicon peruvianum is localized on the short arm of chromosome 6

Abstract

The tomato gene Mi-1 confers resistance to three species of root-knot nematodes, Meloidogyne spp. However, the resistance mediated by Mi-1 is inactive at soil temperatures above 28 degrees C. Previously, we identified and mapped a novel heat-stable nematode resistance gene from the wild species Lycopersicon peruvianum accession LA2157 on to chromosome 6. Here we report further characterization of this heat-stable resistance against three Mi-1-avirulent biotypes of Meloidogyne javanica, Meloidogyne arenaria and Meloidogyne incognita. Screening segregating F(2) and F(3) progenies, derived from an intraspecific cross between susceptible LA392 and resistant LA2157, for nematode resistance at 25 degrees C and 32 degrees C, revealed a simple dominant monogenic inheritance with all the biotypes tested. We designate this gene as Mi-9. As a first step towards cloning of Mi-9, we constructed a linkage map around this gene. A total of 216 F(2) progeny from the cross between LA392 and LA2157 were screened with M. javanica at 32 degrees C and with CT119 and Aps-1, markers that flank the genetic interval that contains the Mi-1 gene. DNA marker analysis indicated that these markers also flank Mi-9. Further mapping of recombinants with both RFLP and PCR-based markers localized Mi-9 to the short arm of chromosome 6 and within the same genetic interval that spans the Mi-1 region.

Early Steps of Tomato Breeding Resist to Root-Knot Nematode

“…The similar result was in Yaghoobi et al (1995) and Ammiraju et al (2003) experiment used the molecular marker method. The gene, which have designated Mi-3 and Mi-9 respectively, confers resistance against nematode strains that can't infect plants carrying Mi.Similar but not same in cotton, Ynturiet al (2004) experiment showed segregation ratio of 3:1 for susceptible and resistant in both F2 populations, suggesting a single recessive gene or one dominant and one recessive gene may be involved in controlling the resistance trait.…”

TheMi-9Gene fromSolanum arcanumConferring Heat-Stable Resistance to Root-Knot Nematodes Is a Homolog ofMi-1

“…For PCR analyses, DNA was isolated from leaflets using Wizard Genomic DNA purification kit (Promega) according to manufacturer's recommendation or as described in Ammiraju et al (2003). For DNA-blot analysis, DNA was isolated, restricted with EcoRV restriction enzyme, and DNA blots prepared according to Kaloshian et al (1998).…”

“…Using a true F 2 segregating population, Mi-9 was mapped to chromosome 6 (Veremis et al, 1999). Mi-9 was further mapped to the short arm of chromosome 6 between markers CT119 and C8B, a similar genetic interval as Mi-1 (Ammiraju et al, 2003).…”

“…1A). To further delimit the Mi-9 location, we screened the F 2 population used previously and derived from a cross between the heatstable root-knot nematode resistance S. arcanum accession LA2157 and the root-knot nematode susceptible accession LA392 (Ammiraju et al, 2003). A total of 589 F 2 progeny plants were scored for DNA markers CT119, Rex-1, C8B, and Aps-1 (Supplemental Table S1).…”

The Potential Role of Binding Proteins in Human Parasitic Infections: An In-Depth Look at the Novel Family of Nematode-Specific Fatty Acid and Retinol Binding Proteins

“…Such an expansion of the analysis to include additional temperatures may be quite relevant, as previous research has demonstrated significant variation in the binding affinities of various proteins to their ligands with regard to environmental temperature [37], and nematodespecific FAR proteins have been shown to be heat-stable [13,20]. Given that plant-parasitic nematodes are much more prevalent during warmer seasons and in tropical climates [38][39][40] and that animal parasites would, by their nature, inhabit warmer environments, it seems possible that FAR studies conducted to date, at 20°C, may not accurately reflect the binding properties of this family of protein in vivo.…”