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Presence of marker mi-23 for resistance to meloidogyne incognita as support to tomato germplasm characterization in Venezuela

Abstract:

Meloidogyne species cause economically significant damage to crops such as tomatoes, inducing galls on roots and causing yellowing of infested plants. The use of resistant cultivars ensures sustainable agriculture and high quality products. We proposed the use of co-dominant marker Mi-23, linked to the resistance gene Mi-1.2, which confers resistance to Meloidogyne spp. To support the characterization of 39 accessions of tomato germplasm from INIA-CENIAP and Lara, including wild tomatoes Solanum pimpinellifolium, and S. lycopersicum local types (Cherry, Pera and Margariteño), advanced populations, and commercial hybrids and varieties. DNA was extracted following CTAB methodology, and PCR amplifications using Mi23F/R primers. Genetic materials formed three groups according to the amplification patterns: 1) population 9, from INIA-Lara, with a fragment of 400 bp, as the DNA control from Belarus; 2) Cherry-Lobatera, Perita Agrovitas, populations 5 and 10, Cherry-189, Mariana and Salad-F1 hybrids, with two fragments of 450 and 400 bp; and 3) the remaining 31 materials, among them, wild tomatoes, locals, advanced populations, and commercial varieties and hybrids, with amplification of a single 450 bp fragment. The first two groups can be correlated to homozygous and heterozygous resistance genotypes, respectively, and the last group to susceptible ones. By using the SCAR marker Mi-23, linked to gen Mi-1.2, we were able to discriminate the INIA tomatoes accessions, and identify eight of them associated with the resistance genotypes to nematode M. incognita, including three advanced populations from INIA-Lara and one local from INIA-CENIAP.