Chemically Defined Elicitors Activate Priming in Tomato Seedlings

Abstract Background: Tomato (Solanum lycopersicum L.) is an important crop that possesses about 35,000 genes. The treatment of plants with elicitors or pathogen attacks causes a cascade of defense reactions. The regulation of metabolic pathways by multigene families at transcriptional and translational levels leads to activation or inhibition of various signaling pathways. We investigated tomato responses to the BamFXTM solution containing Zn and Cu elicitors and report the results of comparative transcriptome analysis of tomato seeds treated with Zn and Cu elicitors. The seeds were treated with optimum concentrations of Bam-FX solutions and subjected to cold methanolic extraction methods to obtain the secondary metabolites produced within them at different time intervals post-Bam-FX treatment. The metabolite mixture was analyzed using gas chromatography-mass spectrometry (GCMS). In transcriptome sequencing, GO and KEGG analyses revealed that the majority of the DEGs in BamFx-treated tomato was associated with primary and secondary metabolism, plant hormone signal transduction, TF regulation, transport, and responses to stimuli. Results: The secondary metabolites found in the BamFX treated tomato seedlings - Esters of Fumaric acid, Succinic acid, thiocyanic acid, octadecanoic acid, benzoic acid, hexenoic acid, heptanoic acid, Nicotinic acids, carbamic acid and Diethylmalonic acid. The transcript levels of most auxin transporter-encoding genes changed significantly in the BamFX-treated seedlings (e.g., Solyc01g007010.3, a RING-type E3 ubiquitin transferase). The gene Solyc07g061720.3 for Gibberellin 2-oxidase and the Phorbol-ester/DAG-type domain-containing protein (Solyc02g068680.1) associated with the intracellular signalling genes were found upregulated in the BamFx-treated seeds. Also, we identified six upregulated genes involved in the protein kinase activity signalling pathways in the BamFX-treated seedlings. The time-dependent effect of the BamFX (1:500 for 60 min) was found to be regulating many signal transduction pathways. Abscisic acid signalling pathway genes (Solyc09g015380.1) were upregulated in BamFX-treated (1:500 for 60 min) plants. Conclusion: This study identified many candidate genes for future functional analyses and laid a theoretical foundation for an improved understanding of the molecular mechanisms involved in the BamFx treatment of tomatoes to improve stress resistance.