Temporal metabolic profiling of the Quercus suber–Phytophthora cinnamomi system by middle‐infrared spectroscopy

Abstract

SummaryThe oomycete Phytophthora cinnamomi is an aggressive plant pathogen, detrimental to many ecosystems including cork oak (Quercus suber) stands, and can inflict great losses in one of the greatest 'hotspots' for biodiversity in the world. Here, we applied Fourier transform-infrared (FT-IR) spectroscopy combined with chemometrics to disclose the metabolic patterns of cork oak roots and P. cinnamomi mycelium during the early hours of the interaction. As early as 2 h post-inoculation (hpi), cork oak roots showed altered metabolic patterns with significant variations for regions associated with carbohydrate, glycoconjugate and lipid groups when compared to mockinoculated plants. These variations were further extended at 8 hpi. Surprisingly, at 16 hpi, the metabolic changes in inoculated and mock-inoculated plants were similar, and at 24 hpi, the metabolic patterns of the regions mentioned above were inverted when compared to samples collected at 8 hpi. Principal component analysis of the FT-IR spectra confirmed that the metabolic patterns of inoculated cork oak roots could be readily distinguished from those of mock-inoculated plants at 2, 8 and 24 hpi, but not at 16 hpi. FT-IR spectral analysis from mycelium of P. cinnamomi exposed to cork oak root exudates revealed contrasting variations for regions associated with protein groups at 16 and 24 h post-exposure (hpe), whereas carbohydrate and glycoconjugate groups varied mainly at 24 hpe. Our results revealed early alterations in the metabolic patterns of the host plant when interacting with the biotrophic pathogen. In addition, the FT-IR technique can be successfully applied to discriminate infected cork oak plants from mock-inoculated plants, although these differences were dynamic with time. To a lesser extent, the metabolic patterns of P. cinnamomi were also altered when exposed to cork oak root exudates.

Evaluating Changes in Cell-Wall Components Associated with Clubroot Resistance Using Fourier Transform Infrared Spectroscopy and RT-PCR

“…Martin et al [ 46 ] used chemical fingerprints to discriminate disease resistant and susceptible clones of Ulmus pumila , and found spectral bands uniquely linked to two phenotypic groups [ 43 , 46 ]. Prior studies have used FTIR spectroscopy in combination with multivariate analysis to determine the changes in the metabolic patterns of tree roots before and after the infection by Phytophthora cinnanoni [ 47 ] or P. Ramorum [ 48 ]. This approach is considered simple, rapid, and cost-effective for high-throughput phenotyping as compared to other laboratory-extraction techniques [ 49 , 50 ] or molecular sequencing techniques [ 51 ].…”

Application of Infrared and Raman Spectroscopy for the Identification of Disease Resistant Trees

“…More recently, Hardoim et al ( 2015 ) used FT-IR spectroscopy and chemometrics to examine changes in the metabolic patterns of Quercus suber roots following infection with the pathogen Phytophthora cinnamomi ; significant differences in the intensity of certain spectral bands were detected between inoculated and mock-inoculated plants. Vivas et al ( 2014 ) also recently used a combined FT-IR spectroscopic and chemometric approach to analyze maternal effects on the MIR spectrum of Pinus pinaster before and after inoculation with the pathogen Fusarium circinatum , the causal agent of pitch canker disease.…”

Disclosing proteins in the leaves of cork oak plants associated with the immune response to Phytophthora cinnamomi inoculation in the roots: A long-term proteomics approach

“…suber root cells, during the first 24 h of interaction with P . cinnamomi , metabolic patterns undergo a non-linear variation for compounds with carbohydrate, glycoconjugate and lipid groups [ 21 ]. At the transcriptomic level, the differential expression of genes encoding pathogenesis-related proteins was observed in avocado roots challenged with P .…”