Altered metabolomic states elicited by Flg22 and FlgII-28 in Solanum lycopersicum: intracellular perturbations and metabolite defenses

Abstract

Background Surveillance of potential pathogens is a key feature of plant innate immunity. For non-self-recognition plants rely on the perception of pathogen-derived molecules. Early post-perception events activate signaling cascades, leading to the synthesis of defense-related proteins and specialized metabolites, thereby providing a broad-spectrum antimicrobial coverage. This study was concerned with tracking changes in the tomato plant metabolome following perception of the flagellum-derived elicitors (Flg22 and FlgII-28). Results Following an untargeted metabolomics workflow, the metabolic profiles of a Solanum lycopersicum cultivar were monitored over a time range of 16–32 h post-treatment. Liquid chromatography was used to resolve the complex mixture of metabolites and mass spectrometry for the detection of differences associated with the elicitor treatments. Stringent data processing and multivariate statistical tools were applied to the complex dataset to extract relevant metabolite features associated with the elicitor treatments. Following perception of Flg22 and FlgII-28, both elicitors triggered an oxidative burst, albeit with different kinetic responses. Signatory biomarkers were annotated from diverse metabolite classes which included amino acid derivatives, lipid species, steroidal glycoalkaloids, hydroxybenzoic acids, hydroxycinnamic acids and derivatives, as well as flavonoids. Conclusions An untargeted metabolomics approach adequately captured the subtle and nuanced perturbations associated with elicitor-linked plant defense responses. The shared and unique features characterizing the metabolite profiles suggest a divergence of signal transduction events following perception of Flg22 vs. FlgII-28, leading to a differential reorganization of downstream metabolic pathways.

Lipopolysaccharides from Ralstonia solanacearum induce a broad metabolomic response in Solanum lycopersicum

“…The overall luminescence results ( Figures 1B, C ) confirmed the host plant’s ability to respond to the LPS R. sol. elicitor through the production of ROS, albeit at a lower metabolic level compared to flagellin-derived peptides flg22 and flg28 ( Zeiss et al, 2021a ).…”

“…This selection was made using the OPLS-DA loading S-plots ( Figure 6B ) and VIP scores ≥2. The cut-off values of |p(corr)| and |(p1)| previously mentioned were determined based on the application of descriptive statistics (ANOVA), which also included the calculation of control- and treatment-averaged peak intensities, the standard deviation, the coefficient of variation, the fold change between the two groups, and the p value on the selected features ( Zeiss et al, 2021a ). In the parameter determination process, a statistical cut-off of p value ≤0.05 was used for ANOVA.…”

“…This strain was used in previous studies regarding the metabo-phenotyping and metabolomics of the host response (disease tolerance) of the selected tomato cvs. ( Zeiss et al, 2018 ; 2019 ) and the inducible changes of the metabolome to peptide elicitors derived from R. solanacearum flagellin ( Zeiss et al, 2021a ) and cold shock protein ( Zeiss et al, 2022 ). LPS was purified from saturated cell cultures grown in the nutrient broth medium on an orbital shaker at 28°C, using the hot phenol protocol as previously described ( Gerber et al, 2004 ) and incorporating DNase and protease digestion steps ( Madala et al, 2011 ).…”

Impact of Rhamnolipids (RLs), Natural Defense Elicitors, on Shoot and Root Proteomes of Brassica napus by a Tandem Mass Tags (TMTs) Labeling Approach

“…It has been shown that elicitors such as flg22 and oligogalacturonides (OGs) positively regulate key genes of secondary metabolism involved in the biosynthesis of glucosinolates, camalexin and phenylpropanoids such as cytochrome P450 (CYP) and PAL genes [45]. Recent metabolomics analysis also showed positive impact of flg22 treatment on secondary metabolites production in tomato [50].…”

The oomycete MAMP, arachidonic acid, and anAscophyllum nodosum-derived plant biostimulant induce defense metabolome remodeling in tomato

“…More recent work in the cells of Sorghum bicolor treated with LPS showed enrichment of hydroxycinnamic acids and other phenylpropanoids in coordination with accumulation of both SA and JA (Mareya et al 2020). Treatment of tomato with flg22 and flgII-28 also enriched hydroxycinnamic acids, and tomato treatment with cps22 revealed a metabolic shift toward the phenylpropanoid pathway with hydroxycinnamic acid, conjugates and derivatives as key biomarkers (Zeiss et al 2021a, b). Similar to traditional MAMPs, AA and the AA/EPA-containing complex mixture, ANE, both induce enrichment of cinnamic acid and derivatives in tomato seedlings (Fig.…”