Metabolic profiling to discriminate wheat near isogenic lines, with quantitative trait loci at chromosome 2DL, varying in resistance to fusarium head blight

Abstract

. 2008. Metabolic profiling to discriminate wheat near isogenic lines, with quantitative trait loci at chromosome 2DL, varying in resistance to fusarium head blight. Can. J. Plant Sci. 88: 789Á797. The resistance in wheat to fusarium head blight (FHB) is controlled by several quantitative trait loci (QTLs), which are mainly expressed as two different types of resistance. The objective of this study was to assess the potential of a metabolomics approach to identify resistance-related metabolites associated with a QTL that confers resistance to FHB. Two near isogenic lines (NIL), with alternate alleles for the FHB resistance/ susceptibility QTL on chromosome 2DL, were grown under greenhouse conditions and spikelets were inoculated with F. graminearum. Metabolites were extracted from the rachis and spikelets using a mixture of methanol-water and chloroform, and subsequently analyzed using GC/MS. Compound identification and quantification were achieved using AMDIS, GMD and NIST libraries, and MET-IDEA as the software platform. A total of 182 components were detected. A t-test of the quantities of these metabolites identified 27 resistance-related (RR) metabolites, including 22 constitutive (RRC) and 8 induced (RRI), with three common metabolites. Canonical discriminant analysis was used to classify treatments and to identify the associated metabolic functions. The putative metabolic pathways linking the RR-metabolites identified here are discussed. Key words: Functional genomics, metabolomics, fusarium head blight, Triticum aestivum, Fusarium graminearumHamzehzarghani, H., Paranidharan, V., Abu-Nada, Y., Kushalappa, A. C., Mamer, O. et Somers, D. 2008. Discrimination des ligne´es de ble´quasi isoge´niques pre´sentant des locus quantitatifs de re´sistance variable a`la bruˆlure de l'e´pi cause´e par fusarium sur le chromosome 2DL par profilage du me´tabolisme. Can. J. Plant Sci. 88: 789Á797. Plusieurs locus quantitatifs codent la re´sistance du ble´a`la bruˆlure de l'e´pi cause´e par Fusarium (BEF). Ces locus expriment surtout deux formes de re´sistance. L'e´tude devait servir a`e´valuer si on peut identifier les me´tabolites lie´s a`cette re´sistance et les associer a`un des locus quantitatifs qui codent la re´sistance a`la BEF par la me´tabolomique. À cette fin, les auteurs ont cultive´en serre deux ligne´es presque isoge´niques mais pre´sentant des alle`les diffe´rents aux locus quantitatifs de re´sistance/sensibilite´a`la BEF sur le chromosome 2DL, puis ont inocule´les e´pillets avec F. graminearum. Ils ont extrait les me´tabolites du rachis et des e´pillets avec un me´lange d'eau-me´thanol et de chloroforme, puis analyse´la solution par CG-SM. Les compose´s ont e´teí dentifie´s et quantifie´s graˆce aux re´pertoires AMDIS, GMD et NIST sur la plateforme logicielle MET-IDEA. En tout, 182 compose´s ont e´te´de´cele´s. Le test t effectue´sur leur quantite´a permis d'en identifier 27 lie´s a`la re´sistance, dont 22 constitutifs et 8 induits, y compris 3 communs. Les traitements ont e´te´classe´s par analyse de discri...

Expression profiling identifies differentially expressed genes associated with the fusarium head blight resistance QTL 2DL from the wheat variety Wuhan-1

“…This suggests that difference in basal level of expression may play an important role in the contribution of a gene to resistance. This is supported by an independent metabolic profiling study on a pair of sister lines segregating for the same 2DL QTL; 22 (out of 27) resistance-related metabolites showed significantly higher levels in the water-inoculated samples of the 2DL-carrying line than in the null line [47]. Transcriptomic studies focusing on the FHB-resistance QTL 3BS and 5A have also identified many genes with difference in basal level of expression between susceptible and resistant members of a pair of lines [24,26].…”

GC–MS based targeted metabolic profiling identifies changes in the wheat metabolome following deoxynivalenol treatment

“…As most of the detected metabolites were annotated using a library created by reference standards, they can be regarded as “level 1 - identified compounds” when utilizing the four levels of metabolite identification proposed by the MSI (Sumner et al 2007 ). We chose a targeted approach predominantly consisting of primary metabolites but also included metabolites that have putatively been related to FHB resistance before (Bollina et al 2011 ; Hamzehzarghani et al 2008 ). Some of the 66 annotated metabolites had to be excluded due to considerable carry over or metabolite levels close to the limit of detection.…”

Transcriptomics of cereal–Fusarium graminearum interactions: what we have learned so far

“…Interestingly, significant differences observed between resistant and susceptible NILs in basal expression levels of a subset of defence genes were not affected by F. graminearum, suggesting that the 2DL-mediated resistance may also be mediated by increased levels of basal defences (Long et al, 2015). Indeed, metabolomic analyses have shown that basal levels of various resistance-related metabolites are higher in resistant than susceptible NILs (Hamzehzarghani et al, 2008). This initial finding has recently led to the identification of the gene underlying the 2DL QTL (see below).…”