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

Xiangning Huang,Arturo A Keller

doi:10.3390/nano11113073

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.

Highlights

Nanosized materials (NMs) are increasingly being considered to improve agricultural sustainability
We hypothesize that the combination of nanoagrochemicals with surfactants can improve the delivery of the active ingredients via foliar applications, for plants with hydrophobic or superhydrophobic leaf surface properties
35.8% of MoO3 NMs was dissolved in SA with 33.5% more

Summary

Introduction

Nanosized materials (NMs) are increasingly being considered to improve agricultural sustainability. Foliar delivery provides an efficient and scalable approach for direct interaction between NMs and plants [12]. To improve the efficiency of foliar application, adjuvants (e.g., humectants, oils, pH buffers, and surfactants) are often employed to improve the wettability of leaf surfaces and prevent off-target drift [16]. We hypothesize that the combination of nanoagrochemicals with surfactants can improve the delivery of the active ingredients via foliar applications, for plants with hydrophobic or superhydrophobic leaf surface properties. The main objectives of this study were to (1) employ a surfactant to improve delivery of NMs to plants; (2) determine whether the surfactant had any effect on the perturbation of target crop metabolic pathways; (3) evaluate the delivery of nano-scale active ingredients through foliar application; and (4) determine the metabolic response of plants to surfactant-enhanced NMs foliar exposure

Objectives

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Results

Conclusion