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Liquid chromatography and high resolution mass spectrometry-based metabolomics to identify quantitative resistance-related metabolites and genes in wheat QTL-2DL against Fusarium head blight

Kage, Udaykumar, Hukkeri, Shivappa, Kushalappa, AjjamadaC.
European journal of plant pathology 2018 v.151 no.1 pp. 125-139
ABC transporters, Fusarium graminearum, Fusarium head blight, biosynthesis, cell walls, cutin, fatty acids, genes, genotype, glyceraldehyde 3-phosphate, greenhouse production, liquid chromatography, mass spectrometry, metabolites, metabolome, metabolomics, microbial biomass, nucleotide sequences, pathogens, phenotype, phenylalanine ammonia-lyase, spikelets, suberin, transferases, wheat
Metabolomics has become a widely-used tool in plants to phenotype different genotypes with varying levels of resistance to stresses. Two near-isogenic lines (NILs) of wheat QTL-2DL, with contrasting levels of resistance to fusarium head blight (FHB), were grown under greenhouse conditions, spikelets were individually inoculated, fungal biomass quantified and the metabolome profiled. The NILs significantly varied in resistance to FHB. The metabolites in phenylpropanoid, fatty acid and glycerophospholipid pathways were highly induced in NIL-R (resistant NIL) relative to NIL-S (susceptible NIL) upon Fusarium graminearum (Fg) inoculation. Key genes involved in the biosynthesis of high fold-change resistance related (RR) metabolites such as genes encoding a glyceraldehyde 3-phosphate acyltransferase (GPAT), an ABC transporter eceriferum 5 (CER5), and a phenylalanine ammonium lyase (PAL), were identified from the QTL-2DL region based on wheat genome survey sequence. Concurrently, relative transcript expressions of these candidate genes were also up-regulated in NIL-R after pathogen inoculation, confirming their potential involvement in the biosynthesis of high fold-change RR metabolites. The spikelet resistance to FHB observed in this study was mainly associated with cell wall reinforcement through deposition of cutin and suberin molecules.