|Di Vito, M|
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2007
Publication Date: 12/31/2007
Citation: Brito, J.A., Stanley, R., Kaur, R., Cetintas, R., Di Vito, M., Thies, J.A., Dickson, D.W. 2007. Effects of the Mi-1, N and Tabasco Genes on Infection and Reproduction of Meloidogyne Mayaguensis on Tomato and Pepper Genotypes. Journal of Nematology. 39:327-332. Interpretive Summary: Meloidogyne mayaguensis, a root-knot nematode that is a serious pest of many ornamental and crop plants, was first reported in the continental United States (Florida) in 2002. Populations of this nematode from Africa and Cuba have been reported to overcome resistance to the root-knot nematode controlled by the Mi-1 gene in tomato. In growth chamber tests, we tested eight populations of M. mayaguensis that had been collected in Florida for their ability to overcome resistance to root-knot nematode in tomato and pepper. In the tomato tests, M. mayaguensis overcame resistance to root-knot nematodes controlled by the Mi-1 gene. In the pepper tests, M. mayaguensis also overcame root-knot nematode resistance controlled by N gene and the Tabasco gene. The ability of M. mayaguensis to overcome the resistance of tomato and pepper varieties that possess the Mi-1, N, and Tabasco genes may limit the use of resistant varieties to manage this nematode in infested tomato and pepper fields in Florida.
Technical Abstract: Meloidogyne mayaguensis is a damaging root-knot nematode that is able to reproduce on root-knot nematode-resistant tomato and other economically important crops. In a growth chamber experiment conducted at 22 and 33 C, isolate 1 of M. mayaguensis reproduced at both temperatures on the Mi-1-carrying tomato lines BHN 543 and BHN 585, whereas M. incognita race 4 failed to reproduce at 22 C, but reproduced well at 33°C. These results were confirmed in another experiment at 26 C where minimal or no reproduction of M. incognita race 4 was observed on the Mi-1-carrying tomato genotypes BHN 543, BHN 585, ‘Sanibel’, and BHN 586, whereas heavy infection and reproduction of M. mayaguensis isolate 1 occurred on these four genotypes. Seven additional Florida M. mayaguensis isolates infected and reproduced on resistant ‘Sanibel’ tomato at 26 C. Isolate 3 was the most virulent with reproduction factor (Rf) equal to 8.4, and isolate 8 was the least virulent (Rf = 2.1). At 24 C, isolate 1of M. mayaguensis reproduced well (Rf less than 1) and induced numerous small galls and large egg masses on the roots of ‘Charleston Belle’, a bell pepper which is homozygous for the N gene that conditions resistance to M. incognita, and on three sweet pepper lines (9913/2, SAIS 97.9001, and SAIS 97.9008) which possess the Tabasco gene for root-knot resistance. In contrast, M. incognita race 4 failed to reproduce or reproduced poorly on these resistant pepper genotypes. The ability of M. mayaguensis isolates to overcome the resistance of tomato and pepper genotypes carrying the Mi-1, N, and Tabasco genes limits the use of resistant cultivars to manage this nematode species in infested tomato and pepper fields in Florida.