Combined Metabonomic and Quantitative RT-PCR Analyses Revealed Metabolic Reprogramming Associated with Fusarium graminearum Resistance in Transgenic Arabidopsis thaliana

Abstract

Fusarium head blight disease resulting from Fusarium graminearum (FG) infection causes huge losses in global production of cereals and development of FG-resistant plants is urgently needed. To understand biochemistry mechanisms for FG resistance, here, we have systematically investigated the plant metabolomic phenotypes associated with FG resistance for transgenic Arabidopsis thaliana expressing a class-I chitinase (Chi), a Fusarium-specific recombinant antibody gene (CWP2) and fused Chi-CWP2. Plant disease indices, mycotoxin levels, metabonomic characteristics, and expression levels of several key genes were measured together with their correlations. We found that A. thaliana expressing Chi-CWP2 showed higher FG resistance with much lower disease indices and mycotoxin levels than the wild-type and the plants expressing Chi or CWP2 alone. The combined metabonomic and quantitative RT-PCR analyses revealed that such FG-resistance was closely associated with the promoted biosynthesis of secondary metabolites (phenylpropanoids, alkanoids) and organic osmolytes (proline, betaine, glucose, myo-inositol) together with enhanced TCA cycle and GABA shunt. These suggest that the concurrently enhanced biosyntheses of the shikimate-mediated secondary metabolites and organic osmolytes be an important strategy for A. thaliana to develop and improve FG resistance. These findings provide essential biochemical information related to FG resistance which is important for developing FG-resistant cereals.

Advances of Metabolomics in Fungal Pathogen–Plant Interactions

“…Therefore, toxin-induced changes in the plant metabolic pathways can be also finely detected by metabolomics. Combined with a variety of omics methods and techniques, metabolomics can also help to screen for resistant varieties and assisted crop breeding [39,41,42,43,44,45].…”

Tricarboxylates Induce Defense Priming Against Bacteria in Arabidopsis thaliana

“…These plants were shown to accumulate up to 2-fold more citrate, suggesting a resistance enhancing effect of higher citrate levels. Recently, enhanced levels of TCA intermediates in the Arabidopsis mutant Chi-CWP2 (expressing a class-I chitinase and a Fusarium -specific recombinant antibody gene) could be linked to resistance against Fusarium graminearum ( Chen et al, 2017 ). On the other hand, TCA cycle inhibition by monofluoroacetate (MFA) triggers citrate accumulation and increases the susceptibility of treated plants to Pseudomonas syringae pv.…”

The versatile GABA in plants

“… 138 Similarly, GABA production is highly induced in stems of Jatropha curcas L. (Euphorbiaceae) infected with the Jatropha mosaic virus (JMV), 139 in tomato leaves infected by Botrytis cinereal , 140 in tobacco leaves infiltrated with a hairpin elicitor, 141 in leaves of potato plants after inoculation with potato virus Y , 142 in leaf apoplast of Phaseolus vulgaris inoculated with P. syringae pv. phaseolicola ( Pph ) 1302A, 143 in Arabidopsis infected with Fusarium graminearum , 144 in diseased Vitis vinifera , 145 and in lettuce inoculated with gray mold. 146 ‘ Candidatus Liberibacter asiaticus ’ and its vector, Diaphorina citri can accelerate cytosolic accumulation of GABA in citrus.…”