Genome sequencing of parthenogenetic Meloidogyne species
Ontology highlight
ABSTRACT: Sequencing the genomes of the parthenogenetic root-knot nematodes Meloidogyne incognita, Meloidogyne javanica and Meloidogyne arenaria for assembly and comparative analysis.
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 biocontrol agent Pythium oligandrum, which is a member of phylum Oomycota, can control diseases caused by a taxonomically wide range of plant pathogens, including fungi, bacteria, and oomycetes. However, whether P. oligandrum could control diseases caused by plant root-knot nematodes (RKNs) was unknown. We investigated a recently isolated P. oligandrum strain GAQ1, and the P. oligandrum CBS530.74 strain, for the control of RKN Meloidogyne incognita infection of tomato (Solanum lycopersicum L.). Initially, P. oligandrum culture filtrates were found to be lethal to M. incognita second-stage juveniles (J2s) with up to 84% mortality at 24 h after treatment compared to 14% in the control group. Consistent with the lethality to M. incognita J2s, tomato roots treated with P. oligandrum culture filtrates reduced the attraction of nematodes, and the number of nematodes penetrating the roots was reduced by up to 78%. In a greenhouse pot trial, P. oligandrum GAQ1 inoculation of tomato plants significantly reduced the gall number by 58% in plants infected with M. incognita. Notably, P. oligandrum GAQ1 mycelial treatment significantly increased tomato plant height (by 36%), weight (by 27%), and root weight (by 48%). Transcriptome analysis of tomato seedling roots inoculated with the P. oligandrum GAQ1 strain identified ~2,500 differentially expressed genes. The enriched GO terms and annotations in the up-regulated genes suggested modulation of plant hormone-signaling and defense-related pathways in response to P. oligandrum. In conclusion, our results support that P. oligandrum GAQ1 can serve as a potential biocontrol agent for M. incognita control in tomato. Multiple mechanisms appear to contribute to the biocontrol effect involving direct inhibition of M. incognita, potential priming of tomato plant defenses, and plant growth promotion.
Project description:Solanum torvum Sw is worldwide employed as rootstock for eggplant cultivation because of its vigour and resistance/tolerance to the most serious soil-borne diseasesas bacterial, fungal wilts and root-knot nematodes. A 30,0000 features custom combimatrix chip was designed and microarray hybridizations were conducted for both control and 14 dpi (day post inoculation) with Meloidogyne incognita-infected roots samples. We also tested the chip with samples from the phylogenetically-related nematode-susceptible eggplant species Solanum melongena.The genes identified from S. torvum catalogue, bearing high homology to knownnematode resistance genes, were further investigated in view of their potential role in the nematode resistance mechanism. total RNA was extracted from control and 14 days post-infection (infection with root-knot nematode Meloidogyne incognita) from roots of Solanum torvum and Solanum melongena. Three biological replicates were used for each condition and genotype for a total of 12 samples.
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:affy_pathogen_medicago - In compatible interaction between plants and biotrophic microorganisms, neoformation of organs occurs to ensure an efficient relationship between both partners. During the interaction between Medicago truncatula and Sinorhizobium meliloti, bacteria induce the development of root nodule with a permanent meristem, and chronically infect plant cells from zone II before differentiating into atmospheric nitrogen fixing bacteroids. M. truncatula is also plant host for root-knot nematodes, such as Meloidogyne incognita. During this compatible pathogenic interaction, root-knot nematodes induce redifferenciation of root cells from the vascular cylinder into specialized feeding cells called “giant cells”. Hyperplasia and hypertrophy of the surrounding cells lead to the formation of typical root galls. This phenomenon invokes host pathways in common with those necessary for nitrogen-nodule formation, suggesting that nematode and rhizobia exploit a relative common strategy of plant cell infection at the cellular and molecular levels. In order to highlight key genes involved in gall and nodule developments, parallel laser microdissection of giant cells from galls and cells from zone II of nodules, followed by transcriptomic analysis, were performed. The RNA pools were extracted from these cells, amplified and used for transcriptomic studies with M. truncatula Affymetrix DNA chips. Keywords: organ comparison 12 arrays - Medicago infected with M. incognita or S. meliloti.
