Comparison between the N and Me3 gene conferring resistance to the root-knot nematode (Meloidogyne incognita) in genetically different pepper lines (Capsicum annuun).

Authors: Thies, Judy; Ariss, Jennifer

Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2009
Publication Date: 8/26/2009
Citation: Thies, J.A., Ariss, J.J. 2009. Comparison between the N and Me3 gene conferring resistance to the root-knot nematode (Meloidogyne incognita) in genetically different pepper lines (Capsicum annuun). European Journal of Plant Pathology. 125(4):545-550.

Interpretive Summary: Root-knot nematodes can be severely damaging to pepper crops, resulting in poor yields and crop failure. The primary chemical control used for nematode pests is methyl bromide, a highly toxic fumigant that is injected directly into the soil. Although methyl bromide is very effective in controlling root-knot nematodes, there are concerns about its effects on the environment. The use of root-knot resistant pepper cultivars could reduce the need for methyl bromide in pepper production. Many genes have been identified in peppers that provide resistance to root-knot nematodes. Two of these genes, which have been named N and Me3, have been separately bred into different pepper varieties. However, no one has determined whether the genes are actually the same gene or two different genes. We used two pepper varieties, one that had the N gene and one with the Me3 gene to breed populations of peppers to study this problem in the greenhouse. From our studies, we discovered that N and Me3 are not different genes, however they may be different forms of the same gene. This information will be useful to pepper breeders and plant pathologists in the development of root-knot nematode resistant pepper hybrids.

Technical Abstract: Genetic resistance to Meloidogyne incognita in pepper (Capsicum annuum L.) has been well characterized for the N and Me3 resistance genes. However, there are no studies comparing the effects of these two genes directly or are there studies investigating the combined effects when both genes are present together. Studies were conducted to investigate the relationship of the N and Me3 gene systems to one another and to assess whether these two genes are allelic or truly separate genes. ‘Charleston Belle’ which is homozygous for the N, and HDA 149, which is homozygous for the Me3 gene, were compared in a replicated greenhouse test for reaction to M. incognita race 3. There were no significant differences between the resistant reactions of genotypes possessing the N or Me3 gene. Allelism tests were performed using the F2 populations of the parental genotypes HDA 149 and ‘Charleston Belle’. The results of these studies indicate that the N and Me3 genes are allelic to each other.