Project description:Soilborne fungal pathogens cause devastating yield losses, are highly persistent and difficult to control. To culminate infection, these organisms must cope with limited availability of iron. Here we show that the bZIP protein HapX functions as a key regulator of iron homeostasis and virulence in the vascular wilt fungus Fusarium oxysporum. Deletion of hapX does not affect iron uptake, but causes derepression of genes involved in iron-consuming pathways, leading to impaired growth under iron-depleted conditions. F. oxysporum strains lacking HapX are reduced in their capacity to invade and kill tomato plants and immunodepressed mice. The virulence defect of M-NM-^ThapX on tomato plants is exacerbated by coinoculation of roots with a biocontrol strain of Pseudomonas putida, but not with a siderophore-deficient mutant, indicating that HapX contributes to iron competition of F. oxysporum in the tomato rhizosphere. These results establish a conserved role for HapX-mediated iron homeostasis in fungal infection of plants and mammals. Iron dependent gene expression in Fusarium oxysporum wt and M-NM-^ThapX mutant was measured 1 hour after shifting the mycelia to minimal medium with or without 50 M-NM-<M Fe2(SO4)3. Three independent experiments were performed.
Project description:The influence of during colonization by Fusarium oxysporum f. sp. Lycopersici secreted effector proteins on the proteome of the xylem sap of tomato plants was investigated using a label-free quantitative proteomics approach. A comparison was made between plants inoculated with either a mock control, a non-effector knockout control, Fusarium oxysporum Fol007 wildtype and four Fol007 single effector protein knockout strains. Specific effects on the relative abundance of certain proteins of the xylem sap occurred for the different knockout strains next to a core set of 24 differentially accumulated proteins which may provide insights into the mechanisms of promoting infection for each of the tested effector proteins.
Project description:Soilborne fungal pathogens cause devastating yield losses, are highly persistent and difficult to control. To culminate infection, these organisms must cope with limited availability of iron. Here we show that the bZIP protein HapX functions as a key regulator of iron homeostasis and virulence in the vascular wilt fungus Fusarium oxysporum. Deletion of hapX does not affect iron uptake, but causes derepression of genes involved in iron-consuming pathways, leading to impaired growth under iron-depleted conditions. F. oxysporum strains lacking HapX are reduced in their capacity to invade and kill tomato plants and immunodepressed mice. The virulence defect of ΔhapX on tomato plants is exacerbated by coinoculation of roots with a biocontrol strain of Pseudomonas putida, but not with a siderophore-deficient mutant, indicating that HapX contributes to iron competition of F. oxysporum in the tomato rhizosphere. These results establish a conserved role for HapX-mediated iron homeostasis in fungal infection of plants and mammals.
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.
Project description:Fungal effectors play important roles in inciting disease development on host plants. We identified an effector (Secreted in Xylem4, SIX4) in an Arabidopsis infecting isolate (Fo5176) of the root-infecting fungal pathogen Fusarium oxysporum and demonstrated this effector is required for full virulence. To explore the role of Fo5176_SIX4 we use whole transcriptome profiling of root tissues from plants overexpressing this effector (35sSIX4) versus wild-type (Col-0) plants after F. oxysporum infection. Published in DOI:10.1007/978-3-319-42319-7_4. Belowground Defence Strategies in Plants.
Project description:Fusarium oxysporum causes Fusarium wilt syndrome in more than 120 different plant hosts, including globally important crops such as tomato, cotton, banana, melon, etc. F. oxysporum shows high host specificity in over 150 formae speciales and have been ranked in the top 10 plant fungal pathogens. Although three PMTs encoded by the pmt1, pmt2, and pmt4 are annotated in the genome of F. oxysporum, their functions have not been reported. As O-mannosylation is not found in plants, a comprehensive understanding of PMTs in F. oxysporum becomes attractive for the development of new strategy against Fusarium wilt. In order to understand the molecular mechanism of the differential functions of three PMTs, a comparative O-glycoproteome analysis of the pmt mutants were carried out.
Project description:Fungal effectors play important roles in inciting disease development on host plants. We identified an effector (Secreted in Xylem4, SIX4) in an Arabidopsis infecting isolate (Fo5176) of the root-infecting fungal pathogen Fusarium oxysporum and demonstrated this effector is required for full virulence. To explore the role of Fo5176_SIX4 we use whole transcriptome profiling of root tissues from plants overexpressing this effector (35sSIX4) versus wild-type (Col-0) plants after F. oxysporum infection. We grew both WT and 35sSIX4 plants for four weeks in soil. After four weeks the plants were infected with Fusarium oxyporum isolate Fo5176, trays covered with a plastic dome and incubated at 28C. There were four independent replicates of each treatment and each replicate contained root tissue from 20 plants. Each replicate (8 in total) was harvested 4 days post inoculation and the resulting RNA was used for hybridization to an Affymetrix ATH1 chip.
Project description:The colonization of Capsicum annuum roots by Fusarium oxysporum Fo47 induces resistance responses on the plant. Fo47 is a non-pathogenic strain of Fusarium oxysporum. Fo47 colonizes only the most outer layers of the root surface but it does not colonize inner tissues. Pre-treatment of roots with Fo47 reduces the symptom development produced by later pathogen inoculation. The expression of genes in distal tissues was determined by microarray analysis of stems of Fo47-treated plants. Capsicum annuum samples were analyzed using Affymetrix chips of the close-related species Solanum lycopersicum.
Project description:Transcriptome analysis reveals the response mechanism of Frl-mediated resistance to Fusarium oxysporum f. sp. radicis-lycopersici (FORL) infection in tomato
Project description:The transcription factor Mac1 is a key regulator of copper homeostasis, controlling the transcriptional response to copper-limiting conditions in fungi. It has been described as a virulence factor in human pathogens such as Candida albicans and Aspergillus fumigatus, but surprisingly its role in plant pathogenesis is poorly understood. Targeted deletion of Mac1 in the soilborne pathogen Fusarium oxisporum results in an inability to grow under copper-limited conditions and kills tomato plants. The aim of this RNA-seq analysis is to elucidate the role of Mac1 in gene regulation under copper starvation and during infection of tomato plants by F. oxysporum.