Project description:Magnaporthe oryzae (rice blast) and the root-knot nematode Meloidogyne graminicola are causing two of the most important pathogenic diseases jeopardizing rice production. Here, we show that root-knot nematode infestation on rice roots leads to important above-ground changes in plant immunity gene expression, which is correlated with significantly enhanced susceptibility to blast disease.
Project description:We compared the gene expression of wild-type Col-0 and a T-DNA mutant SALK_116381C (opr2-1). We either infected or mock-infected the plants with the root knot nematode Meloidogyne incognita and measured the root transcriptome after 0, 1, 4, and 7 days post infection using RNA-seq. The aim of the experiment was to determine whether opr2-1 affected gene expression patterns induced by nematode infection.
Project description:High-coverage whole genome sequencing of 11 Brazilian isolates of the root-knot nematode Meloidogyne incognita, presenting different host plant preferences and different geographical origins. Four M. incognita host races had been proposed in the past, based on host (in)compatibility on four different plant strains. The objective was to assess whether genomic variations (SNP) correlate with host range compatibility, geographical origin and host plant of origin.
Project description:The global imperative to enhance crop protection while preserving the environment has increased interest in the application of biological pesticides. Bacillus thuringiensis (Bt) is a Gramm-positive bacterium that can produce nematicidal proteins and accumulate them in parasporal crystals. Root-knot nematodes are obligate root plant parasitic which are distributed worldwide, causing severe damages to the infested plants and, consequently, large yield reductions. In this work, we have evaluated the toxicity of the crystal proteins Cry5, Cry21, App6, and Xpp55 against two root-knot nematodes belonging to the Meloidogyne genus (M. incognita and M. javanica). The results show that all four proteins, when solubilized, were highly toxic for both nematode species. To check the potential of using Bt strains producing nematicidal crystal proteins as biopesticides to control plant parasitic nematodes in the field, in planta assays were conducted, using two wild Bt strains which produced Cry5 or a combination of App6 and Cry5 proteins. The tests were carried out with cucumber or with tomato plants infested with M. javanica J2, subjected to irrigation with spore+cristal mixtures of the respective strains. The results showed that the efficacy of the nematicidal activity was plant-dependent, as Bt was able to reduce emerged J2 in tomato plants but not in cucumber plants. In addition, the toxicity observed in the in planta assays was much lower than expected, highlighting the challenge of the crystal proteins to exert their toxicity. This emphasizes the delivery of the Bt proteins as crucial for its use to control root-knot nematodes.
