Plant parasitic nematodes from the genus Meloidogyne cause significant economic losses in solanaceous and cucurbit crops. Plant resistance reduces the rate of nematode population development and the damage that it causes to the crop, and to the next crop in the rotation. However, its continous use favors the selection of virulent populations able to break the resistance. The frequency of detection of virulent populations to the Mi1.2 gene in tomato and Me3-Me7 in pepper is increasing, however this situation could be revert. Recently, results from a two years rotation including tomato grafted on the resistant cv. Aligator-melon on Cucumis metuliferus carried out by part of our research team, have shown that a highly virulent population to the Mi1.2 gene was selected at the end of the first tomato crop, but the degree of virulence decreased progressively until the 10% of the initial one at the end of the second melon crop. Thus, the hypothesis of work is that if a higher diversity of resistance genes is included in the rotation sequence it will induce physiological changes in the nematode that are transmitted to the next nematode generation decreasing the degree of virulence. In addition, the plant genetic resistance could be improved combining resistant cultivars with microorganisms inducers of plant defenses, but it could affect the natural antagonist microbiota from suppressive soils to Meloidogyne. Accordingly, the main objective of this project is to design Meloidogyne resistant plant germplasm management strategies to inhibit the selection of virulent populations by two approaches: 1) by characterization of resistant plant germplasm and its effect on virulence selection when are included in a crop rotation system. 2) by improving the plant resistance by combining the resistant plant germplasm with resistance inducer microorganisms. Concerning the second approach, we will also want to know the effect of those inducer microorganisms on the natural nematode antagonists from suppressive soils. The use of commercial formulations containing biological control agents of plant-pathogenic fungi which, in addition, can induce plant defense mechanisms against plant parasitic nematodes is becoming more frequent. Nevertheless, little is known about its effect on the natural nematode antagonistic microbiota, such as the nematode egg parasite Pochonia chlamydosporia characterized, from part of the research team, as responsible of Meloidogyne sp. suppression in agricultural soils. The final objective of the project is to make a draft of the manual of good plant resistance practices for using against Meloidogyne in horticultural crops, as a tool for helping growers to prevent the selection of virulent populations and to avoid secundary effects such as the reduction of the natural antagonistic microbiota from agricultural soils. The results from this project would improve nematode management strategies by reducing the use of chemical nematicides, the cropping costs, the environmental impact, and workers and consumers health risk, to facilitate the transition to more sustainable agricultural production systems.
Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016
Programa Estatal de I+D+i Orientada a los Retos de la Sociedad