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:We performed RNA-seq analysis of the root transcriptional response to Fusarium oxysporum f.sp. vasinfectum (FOV) race 4 (FOV4) infection in Gossypium barbadense, also known as Pima cotton. Susceptible Gossypium barbadense inbred lines Pima S-7 (PI 560140) and Pima 3-79 susceptible to Fusarium wilt [Fusarium oxysporum f.sp. vasinfectum (FOV)] race 4 (FOV4), and Pima S-6 (PI 608346) which is resistant to FOV4 infection, were used for the preparation of cDNA libraries and further RNA-seq analyses. An isolate of FOV4 (FOV CA-14) from a naturally infested field in Fresno County in the San Joaquin Valley, California was used in this study.
Project description:Watermelon (Citrullus lanatus) is one of the most important vegetable crops in the world and accounts for 20% of the world’s total area devoted to vegetable production. Fusarium wilt of watermelon is one of the most destructive diseases in watermelon worldwide. Transcriptome profiling of watermelon during its incompatible interactions with Fusarium oxysporum f.sp. niveum (FON) was generated using an Agilent custom microarray which contains 15,000 probes representing approximately 8,200 watermelon genes. A total of 24, 275, 596, 598, and 592 genes that are differentially expressed genes between FON- and mock-inoculated watermelon roots at 0.5, 1, 3, 5 and 8 days post inoculation (dpi), respectively, were identified. Bioinformatics analysis of these differentially expressed genes revealed that during the incompatible interaction between watermelon and FON, the expression of a number of pathogenesis-related (PR) genes, transcription factors, signaling/regulatory genes, and cell wall modification genes, was significantly induced. A number of genes for transporter proteins such as aquaporins were down-regulated, indicating that transporter proteins might contribute to the development of wilt symptoms after FON infection. In the incompatible interaction, most genes involved in biosynthesis of jasmonic acid (JA) showed expressed stronger and more sustained than those in compatible interaction in FON-infected tissues. Similarly, genes associated with shikimate-phenylpropanoid-lignin biosynthesis were also induced in incompatible interaction, but expression of these genes were not changed or repressed in the compatible interaction. Fusarium oxysporum f.sp. niveum induced gene expression in watermelon root was measured at 0.5,1d, 3d, 5d and 8d after inoculation. Sample inoculated with water were used as the mock controls. Three independent experiments were performed.
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:MicroRNAs (miRNAs) are a class of endogenous non-coding small RNAs that regulate targeted mRNAs by degrading or repressing translation, considered as post-transcrption regulators. So far, a large number of miRNAs have been discovered in model plants, but little information is available on miRNAs in banana. In this study, by sequencing the small RNA (sRNA) transcriptomes of Fusarium wilt resistant and susceptible banana varieties, 139 members in 38 miRNA families were discovered, and six out of eight new miRNAs were confirmed by RT-PCR. According to the analysis of sRNA transcriptome data and qRT-PCR verification, some miRNAs were differentially expressed between Fusarium wilt resistant and susceptible banana varieties. Two hundred and ninety-nine and 31 target genes were predicted based on the draft maps of banana B genome and Fusarium oxysporum (FOC1, FOC4) genomes respectively. Specifically, two important pathogenic genes in Fusarium oxysporum genomes, feruloyl esterase gene and proline iminopeptidase gene, were targeted by banana miRNAs. These novel findings may provide a new strategy for the prevention and control of Fusarium wilt in banana.
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:Eggplant is susceptible to fungal wilts caused by Fusarium oxysporum f. sp. melongenae and Verticillium dahliae. Wild relatives represent a good source of resistance and ILs have been obtained through introgression of the Rfo-sa1 locus conferring resistance to Fusarium oxysporum from the allied species S. aethiopicum into cultivated eggplant. In this work, a deep phenotypical characterization was performed according to the progression of symptoms along the stem and the disease severity in leaves. This analysis showed that the Fom -resistant ILs carrying introgression of the Rfo-sa1 locus displayed significantly improved tolerance to Verticillium attack after a preliminary inoculation with F. oxysporum. This positive effect was particularly evident when Verticillium inoculation was done simultaneously or after the Fusarium one. Transcript profiling carried out using a combination of SSH, microarray and qRT-PCR analyses from inoculated roots with a selected combinations of fungal pathogens enabled the identification of 164? differentially expressed genes at least in one condition. Overall, our results highlighted a number of candidate genes putatively involved in early defence responses or signalling pathways activated upon infection of eggplant either with Fom and Vd and thus leading to a broad Rfo-sa1 mediated tolerance against both these wilt pathogens.
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:Fusarium oxysporum is one of the most common species causing soybean root rot and seedling blight in the U.S. In a recent study, significant variation in aggressiveness was observed among isolates of F. oxysporum collected from roots in Iowa, ranging from highly pathogenic to weakly or non-pathogenic isolates. In the present work, a RNA-seq-based analysis was used for the first time to investigate the molecular aspect of the interaction of a partially resistant soybean genotype with non-pathogenic/pathogenic isolates of F. oxysporum at 72 and 96 hours post inoculation (hpi). Markedly different gene expression profiles were observed in compatible and incompatible host-pathogen combinations. A peak of differentially expressed genes (DEGs) was observed at 72 hpi in soybean roots in response to both isolates, although the number of DEGs was about eight times higher for the pathogenic isolate compared to the non-pathogenic one (1,659 vs. 203 DEGs, respectively). Furthermore, not only the number of genes, but also the magnitude of induction was much greater in response to the pathogenic isolate. This response included a stronger activation of many well-known defense-related genes, and several genes involved in ethylene biosynthesis and signalling, transcription factors, secondary and sugar metabolism. In addition, 1130 fungal genes were differentially expressed between the F. oxysporum isolates in planta during the infection process. Interestingly, 10% of these genes encode plant cell-wall degrading enzymes, reactive oxygen species-related enzymes and fungal proteins involved in primary metabolic pathways. Such information may be useful in the development of new methods of broadening resistance of soybean to F. oxysporum, including the silencing of important fungal genes, and also to understand the molecular basis of soybean-F. oxysporum interactions. Soybean seedlings mRNA profiles inoculated with a non-pathogenic and pathogenic isolates of F. oxysporum and collected at 72 and 96 hpi, were generated using Illumina HiSeq 2500. Control seedlings were also included for each time of inoculation. Three biological replicates were considered for each condition, 18 samples in total.
Project description:Watermelon (Citrullus lanatus) is one of the most important vegetable crops in the world and accounts for 20% of the world’s total area devoted to vegetable production. Fusarium wilt of watermelon is one of the most destructive diseases in watermelon worldwide. Transcriptome profiling of watermelon during its incompatible interactions with Fusarium oxysporum f.sp. niveum (FON) was generated using an Agilent custom microarray which contains 15,000 probes representing approximately 8,200 watermelon genes. A total of 24, 275, 596, 598, and 592 genes that are differentially expressed genes between FON- and mock-inoculated watermelon roots at 0.5, 1, 3, 5 and 8 days post inoculation (dpi), respectively, were identified. Bioinformatics analysis of these differentially expressed genes revealed that during the incompatible interaction between watermelon and FON, the expression of a number of pathogenesis-related (PR) genes, transcription factors, signaling/regulatory genes, and cell wall modification genes, was significantly induced. A number of genes for transporter proteins such as aquaporins were down-regulated, indicating that transporter proteins might contribute to the development of wilt symptoms after FON infection. In the incompatible interaction, most genes involved in biosynthesis of jasmonic acid (JA) showed expressed stronger and more sustained than those in compatible interaction in FON-infected tissues. Similarly, genes associated with shikimate-phenylpropanoid-lignin biosynthesis were also induced in incompatible interaction, but expression of these genes were not changed or repressed in the compatible interaction.