Biostimulants for Plant Growth and Mitigation of Abiotic Stresses: A Metabolomics Perspective

Abstract

Adverse environmental conditions due to climate change, combined with declining soil fertility, threaten food security. Modern agriculture is facing a pressing situation where novel strategies must be developed for sustainable food production and security. Biostimulants, conceptually defined as non-nutrient substances or microorganisms with the ability to promote plant growth and health, represent the potential to provide sustainable and economically favorable solutions that could introduce novel approaches to improve agricultural practices and crop productivity. Current knowledge and phenotypic observations suggest that biostimulants potentially function in regulating and modifying physiological processes in plants to promote growth, alleviate stresses, and improve quality and yield. However, to successfully develop novel biostimulant-based formulations and programs, understanding biostimulant-plant interactions, at molecular, cellular and physiological levels, is a prerequisite. Metabolomics, a multidisciplinary omics science, offers unique opportunities to predictively decode the mode of action of biostimulants on crop plants, and identify signatory markers of biostimulant action. Thus, this review intends to highlight the current scientific efforts and knowledge gaps in biostimulant research and industry, in context of plant growth promotion and stress responses. The review firstly revisits models that have been elucidated to describe the molecular machinery employed by plants in coping with environmental stresses. Furthermore, current definitions, claims and applications of plant biostimulants are pointed out, also indicating the lack of biological basis to accurately postulate the mechanisms of action of plant biostimulants. The review articulates briefly key aspects in the metabolomics workflow and the (potential) applications of this multidisciplinary omics science in the biostimulant industry.

A Metabolomic Landscape of Maize Plants Treated With a Microbial Biostimulant Under Well-Watered and Drought Conditions

“…This knowledge-gap hampers industries and famers from confidently and innovatively formulating and fully implementing the use of biostimulants into agronomic practices ( Rouphael et al, 2020 ). Omics sciences, particularly metabolomics, are emerging as indispensable approaches in decoding the mechanisms of action employed by biostimulants ( Nephali et al, 2020 ). Recent metabolomics studies have shown that a microbial biostimulant increased the yield of sweet pepper by inducing a metabolic readjustment of hormones and secondary metabolism ( Bonini et al, 2020 ).…”

Uncovering the multi-level response of Glycine max L. to the application of allelopathic biostimulant from Levisticum officinale Koch

“…However, it should be emphasized that the cause-and-effect relationship between the application of biostimulants, phenotypic evaluation of the treated plants and the accumulation of solutes and protection against stress is still not fully understood 43 . According to Nephali et al 44 even more careful research doesn't always show a clear answer. It turns out that changes on the transcriptome or proteome levels do not always correspond to changes in biochemical phenotypes.…”

Biostimulants as Plant Growth Stimulators in Modernized Agriculture and Environmental Sustainability

“…As describes earlier, plant biostimulants improve nutrient availability, uptake, translocation, and assimilation, which is beneficial to organic farming. In addition, incredible results can be obtained with the integrated application of biostimulants with chemical fertilizers in soil [26]. It contributes to improving the cation exchange capacity of the soil and enhances the solubility of the nutrients in soil solution which subsequently increases the nutrient availability for plant uptake [8].…”