Metabolomic Response of Early-Stage Wheat (Triticum aestivum) to Surfactant-Aided Foliar Application of Copper Hydroxide and Molybdenum Trioxide Nanoparticles

Abstract

Surfactants are commonly used in foliar applications to enhance interactions of active ingredients with plant leaves. We employed metabolomics to understand the effects of TritonTM X-100 surfactant (SA) and nanomaterials (NMs) on wheat (Triticum aestivum) at the molecular level. Leaves of three-week-old wheat seedlings were exposed to deionized water (DI), surfactant solution (SA), NMs-surfactant suspensions (Cu(OH)2 NMs and MoO3 NMs), and ionic-surfactant solutions (Cu IONs and Mo IONs). Wheat leaves and roots were evaluated via physiological, nutrient distribution, and targeted metabolomics analyses. SA had no impact on plant physiological parameters, however, 30+ dysregulated metabolites and 15+ perturbed metabolomic pathways were identified in wheat leaves and roots. Cu(OH)2 NMs resulted in an accumulation of 649.8 μg/g Cu in leaves; even with minimal Cu translocation, levels of 27 metabolites were significantly changed in roots. Due to the low dissolution of Cu(OH)2 NMs in SA, the low concentration of Cu IONs induced minimal plant response. In contrast, given the substantial dissolution of MoO3 NMs (35.8%), the corresponding high levels of Mo IONs resulted in significant metabolite reprogramming (30+ metabolites dysregulated). Aspartic acid, proline, chlorogenic acid, adenosine, ascorbic acid, phenylalanine, and lysine were significantly upregulated for MoO3 NMs, yet downregulated under Mo IONs condition. Surprisingly, Cu(OH)2 NMs stimulated wheat plant tissues more than MoO3 NMs. The glyoxylate/dicarboxylate metabolism (in leaves) and valine/leucine/isoleucine biosynthesis (in roots) uniquely responded to Cu(OH)2 NMs. Findings from this study provide novel insights on the use of surfactants to enhance the foliar application of nanoagrochemicals.

The Effect of Bio-Synthesized Silver Nanoparticles on Germination, Early Seedling Development, and Metabolome of Wheat (Triticum aestivum L.)

“…In endosperm, the levels of total amino acids (TAAs) and TOAs declined ( Figure 6 C,D). Presumably, drastic changes in tissues metabolism by using Ag NPs are closely related to seedling growth and development, as it was found earlier after the foliar application of copper and manganese NPs on 3-week-old wheat plants [ 56 , 57 ], as well as in Ag NPs treated Arabidopsis thaliana [ 57 , 58 ]. The results of PCA analysis of our results, confirm that (Bio)Ag NPs considerably affected profiles and metabolite contents in tissues of roots and coleoptile.…”

Metabolomics Response of Wheat (Triticum aestivum) to “Green” and Conventional Nonionic Surfactants at Different Application Stages

“…Depending on the structure of leaf epicuticular wax and trichome density, the water contact angle could be as high as 150 °C, causing sprayed droplets to easily run off or even be repelled . Under such circumstances, SAs are used to assist spray application to deliver fertilizers, , pesticides, , and microbial inoculants. , SAs are classified as anionic, cationic, nonionic, and amphoteric based on the nature of hydrophilic group properties . Many common SAs are derived from petrochemicals.…”

“…The authors proposed that ionic adsorption was likely the dominant pathway though the cuticular pathway. Most of the above-mentioned studies only considered the surfactant as a wetting agent, however, plant molecular response caused by the surfactant has seldomly been examined . Furthermore, most studies examined plant response at one single time, instead of considering plant response at various times after the exposure assay.…”

“…Metabolites are the end products of plant regulatory processes at the molecular level. In addition to physiological phenotypic expression, metabolomics allows to distinguish and quantify molecular level changes within plants and the rhizosphere. ,− However, only a few studies have conducted a quantitative metabolite comparison (targeted metabolomics), ,,− while other studies were either semiquantitative (untargeted) − or evaluated the total content of only certain metabolite groups (e.g., sugars, phenolics, nonenzymatic antioxidants, etc. ). , A recent study employed the commercial surfactant TritonX-100 to improve the foliar application of Cu­(OH) 2 NMs and MoO 3 NMs to early-stage wheat seedlings .…”

“…Leucine, lysine, phenylalanine, proline, serine, tryptophan, linolenic acid, adenosine, guanosine, uridine, and trehalose had more than 5 times fold changes in wheat leaves and roots. Metabolomics further demonstrated the favoring of N metabolism over C metabolism, potential membrane lipid peroxidation, and perturbation of pyrimidine and purine metabolism to defend against stress …”