Metabolomic analysis reveals a common pattern of metabolic re-programming during invasion of three host plant species by Magnaporthe grisea.

Institute of Biological Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, UK.
The Plant Journal (Impact Factor: 6.82). 06/2009; 59(5):723-37. DOI: 10.1111/j.1365-313X.2009.03912.x
Source: PubMed

ABSTRACT The mechanisms by which biotrophic and hemi-biotrophic fungal pathogens simultaneously subdue plant defences and sequester host nutrients are poorly understood. Using metabolite fingerprinting, we show that Magnaporthe grisea, the causal agent of rice blast disease, dynamically re-programmes host metabolism during plant colonization. Identical patterns of metabolic change occurred during M. grisea infections in barley, rice and Brachypodium distachyon. Targeted metabolite profiling by GC-MS confirmed the modulation of a conserved set of metabolites. In pre-symptomatic tissues, malate and polyamines accumulated, rather than being utilized to generate defensive reactive oxygen species, and the levels of metabolites associated with amelioration of redox stress in various cellular compartments increased dramatically. The activity of NADP-malic enzyme and generation of reactive oxygen species were localized to pathogen penetration sites, and both appeared to be suppressed in compatible interactions. Early diversion of the shikimate pathway to produce quinate was observed, as well as accumulation of non-polymerized lignin precursors. These data are consistent with modulation of defensive phenylpropanoid metabolism by M. grisea and the inability of susceptible hosts to mount a hypersensitive reaction or produce lignified papillae (both involving reactive oxygen species) to restrict pathogen invasion. Rapid proliferation of M. grisea hyphae in plant tissue after 3 days was associated with accelerated nutrient acquisition and utilization by the pathogen. Conversion of photoassimilate into mannitol and glycerol for carbon sequestration and osmolyte production appear to drive hyphal growth. Taken together, our results suggest that fungal pathogens deploy a common metabolic re-programming strategy in diverse host species to suppress plant defence and colonize plant tissue.


Available from: David P Enot, May 12, 2015
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Producing a comprehensive overview of the chemical content of biologically-derived material is a major challenge. Apart from ensuring adequate metabolome coverage and issues of instrument dynamic range, mass resolution and sensitivity, there are major technical difficulties associated with data pre-processing and signal identification when attempting large scale, high-throughput experimentation. To address these factors direct infusion or flow infusion electrospray mass spectrometry has been finding utility as a high throughput metabolite fingerprinting tool. With little sample pre-treatment, no chromatography and instrument cycle times of less than 5 min it is feasible to analyse more than 1,000 samples per week. Data pre-processing is limited to aligning extracted mass spectra and mass-intensity matrices are generally ready in a working day for a month’s worth of data mining and hypothesis generation. ESI-MS fingerprinting has remained rather qualitative by nature and as such ion suppression does not generally compromise data information content as originally suggested when the methodology was first introduced. This review will describe how the quality of data has improved through use of nano-flow infusion and mass-windowing approaches, particularly when using high resolution instruments. The increasingly wider availability of robust high accurate mass instruments actually promotes ESI-MS from a merely fingerprinting tool to the ranks of metabolite profiling and combined with MS/MS capabilities of hybrid instruments improved structural information is available concurrently. We summarise current applications in a wide range of fields where ESI-MS fingerprinting has proved to be an excellent tool for “first pass” metabolome analysis of complex biological samples. The final part of the review describes a typical workflow with reference to recently published data to emphasise key aspects of overall experimental design.
    Metabolomics 03/2012; 9(S1):4-29. DOI:10.1007/s11306-012-0449-x · 3.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Soybean germplasm exhibits various levels of resistance to Fusarium tucumaniae, the main causal agent of sudden death syndrome (SDS) of soybean in Argentina. In this study, two soybean genotypes, one susceptible (NA 4613) and one partially resistant (DM 4670) to SDS infection, were inoculated with F. tucumaniae. Disease symptoms were scored at 7, 10, 14, and 25 days post-inoculation (dpi). The greatest difference in the area under the disease progress curve (AUDPC) values among genotypes was observed at 25 dpi. In order to detect early metabolic markers that could potentially discriminate between susceptible and resistant genotypes, gas chromatography-mass spectrometry (GC-MS) analyses of root samples were performed. These analyses show higher levels of several amino acids and the polyamine cadaverine in the inoculated than in the uninoculated susceptible cultivar at 7 dpi. Principal component analysis (PCA) revealed that the metabolic profile of roots harvested at the earliest time points from the inoculated susceptible genotype was clearly differentiated from the rest of the samples. Furthermore, variables associated with the first principal component were mainly amino acids. Taken together, the results indicate that the pathogen induced the susceptible plant to accumulate amino acids in roots at early time points after infection, suggesting that GC-MS-based metabolomics could be used for the rapid characterization of cultivar response to SDS.
    Journal of Experimental Botany 10/2014; DOI:10.1093/jxb/eru432 · 5.79 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Suppressive ability of several strains of cyclic lipopeptide-producing Bacillus rhizobacteria to gray leaf spot disease caused by Magnaporthe oryzae was previously documented, however, underlying mechanism(s) involved in the induced systemic resistance (ISR) activity in perennial ryegrass (Lolium perenne L.) remained unknown. Root-drench application of SPE (solid-phase extraction)- enriched surfactin, and live cells of mutant Bacillus amyloliquefaciens FZB42-AK3 strain (produces surfactin, but not bacillomycin D and fengycin) significantly reduced disease incidence and severity on perennial ryegrass. Application of treatments revealed a pronounced multilayered ISR defense response activation through timely and enhanced accumulation of hydrogen peroxide (H2O2), elevated cell wall/apoplastic peroxidase activity, deposition of callose, and phenolic/polyphenolic compounds, underneath the fungal appressoria in the naïve leaves that were significantly more intense in treated plants than mock treated control. Moreover, hypersensitive response (HR)-type reaction and enhanced expression of LpPrx, LpOXO4, LpPAL, LpLOXa, LpTHb (putative-defensin), and LpDEFa (putative-defensin) in perennial ryegrass were associated with SPE-surfactin and live AK3 cell treatments, acting as a second-layer of defense when pre-invasive defense responses failed. The results indicate that ISR activity following surfactin perception may sensitize H2O2 mediated defense responses, thereby provide perennial ryegrass with enhanced protection against M. oryzae.
    Molecular Plant Pathology 10/2014; DOI:10.1111/mpp.12209 · 4.49 Impact Factor