A Metabolic Choreography of Maize Plants Treated with a Humic Substance-Based Biostimulant under Normal and Starved Conditions

Abstract

Humic substance (HS)-based biostimulants show potentials as sustainable strategies for improved crop development and stress resilience. However, cellular and molecular mechanisms governing the agronomically observed effects of HS on plants remain enigmatic. Here, we report a global metabolic reprogramming of maize leaves induced by a humic biostimulant under normal and nutrient starvation conditions. This reconfiguration of the maize metabolism spanned chemical constellations, as revealed by molecular networking approaches. Plant growth and development under normal conditions were characterized by key differential metabolic changes such as increased levels of amino acids, oxylipins and the tricarboxylic acid (TCA) intermediate, isocitric acid. Furthermore, under starvation, the humic biostimulant significantly impacted pathways that are involved in stress-alleviating mechanisms such as redox homeostasis, strengthening of the plant cell wall, osmoregulation, energy production and membrane remodelling. Thus, this study reveals that the humic biostimulant induces a remodelling of inter-compartmental metabolic networks in maize, subsequently readjusting the plant physiology towards growth promotion and stress alleviation. Such insights contribute to ongoing efforts in elucidating modes of action of biostimulants, generating fundamental scientific knowledge that is necessary for development of the biostimulant industry, for sustainable food security.

Metabolomics and Chemoinformatics in Agricultural Biotechnology Research: Complementary Probes in Unravelling New Metabolites for Crop Improvement

“…Other metabolomics techniques include high-performance thin-layer chromatography (HPTLC), direct-infusion mass spectrometry (DIMS), Fourier transform ion-cyclotron resonance mass spectrometry (FI-ICR-MS), and capillary electrophoresis–mass spectrometry (CE-MS) [ 24 , 25 , 33 , 34 ]. Applying these techniques has made it possible to monitor plant responses and metabolic reprogramming under biotic [ 35 , 36 ] and abiotic stress [ 37 , 38 ], as further discussed in plant metabolomics applications for crop improvement strategies.…”

“…Furthermore, Othibeng and colleagues [ 38 ] reported an increase in phytohormones such as indole-3-acetic acid (IAA) and salicylic acid (SA), which are responsible for plant regulatory processes such as seed germination and seedling growth, using an untargeted metabolomics approach and chemoinformatics tools and databases such as PubChem, Chemspider, and the Dictionary of Natural Products for metabolite annotation. The studies mentioned above applied the advantages of metabolomics technologies, combined with chemometrics and chemoinformatics tools, to probe the roles of essential metabolites in plant growth and development.…”

Humic Substances as Microalgal Biostimulants—Implications for Microalgal Biotechnology

“…In sugarcane, Saccharum officinarum cv. RB 96 7515, application of HA extracted from vermicompost activated the metabolic pathways related to plant stress response and cellular growth [ 47 ]. In corn, Zea mays cv.…”

Metabolic Circuits in Sap Extracts Reflect the Effects of a Microbial Biostimulant on Maize Metabolism under Drought Conditions

“…Interrogating plant metabolism through omics approaches, such as metabolomics, enables the decoding of the language of cells at a molecular level. In the context of biostimulant-plant interactions, such accurate metabolic models are imperatively essential for devising and designing a roadmap for the next generation of biostimulant formulations and strategies for high productivity and resilience to climate change [10,14].…”