(344a) Time-Dependent Enrichment of Stress-Induced Biomarkers in Plants Using Nanoparticle Protein Coronas

Global food demand is projected to grow by 60% over the next 20 years. Climate change, pathogens, and environmental stressors compromise food security by reducing agricultural productivity and crop quality. Nanobiotechnology, which adapts nano-scale materials as carriers and sensors, has made several strides for crop biofortification applications, including the development of nano-sensors that can detect single phytohormones or signalling molecules. However, ‘single-signal’ nano-sensors do not provide a comprehensive understanding of plant stress as stress-induced responses are highly complex and involve multiple biomolecules and biochemical pathways. When nanomaterials are delivered into biological systems, their surfaces become spontaneously coated with biomolecules forming nanoparticle-corona complexes that can be analysed with high resolution instruments. Analogous mammalian studies have shown that nanoparticle interactions with biological fluids, such as blood and gastrointestinal secretions, can be harnessed for the identification of low-abundance biomarkers for presymptomatic disease diagnosis. In this study, we hypothesized that the intrinsic interactions between nanomaterials and plant biomolecules could be harnessed as a nano-tool for the highly sensitive enrichment of stress biomarkers in plants and crops prior to the expression of phenotypic symptoms.

Herein, we exposed plant and crop species to a pathogenic bacterium, Pseudomonas syringae, to prompt a temporal production of multiple stress-induced biomarkers. We collected time-dependent tissue from infected (0.5-, 1-, 3-, and 7-days post infection) Arabidopsis thaliana and Zea mays plants and used 10 nm gold nanoparticles (AuNPs) with different surface charges to enrich and detect stress induced biomarkers through a nano-omics approach (Figure 1). Specifically, our nano-omics approach leverages nanoparticle-corona formation and subsequent analysis with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). For plants analyzed with conventional UHPLC-MS/MS alone, molecular stress markers alerted the onset of infection at the same time as visual inspection of the temporal development of phenotypic symptoms ≥3 days post infection. Contrastingly, our highly sensitive nano-omics results show that several unique stress-induced biomarkers, enriched on AuNPs with certain surface chemistries, were detectable in ‘healthy-appearing’ plants at early stages of infection (≤1 day post infection) prior to the onset of phenotypic responses (i.e.: wilting, chlorosis, necrosis). Most interestingly, the sensitivity of our nano-omic approach extended to neighboring ‘distal’ tissues of infected plants. P. syringae, which colonizes the apoplast of directly infected leaves, was itself not detected in ‘distal’ leaves, but our nano-omics approach sensitively detected biomarkers of stress in these neighboring tissues triggered by immune signaling. While this study focused on two different plant species, and one form of biotic stress, we anticipate that this method can also be applied to detect biomarkers in other agriculturally relevant crops induced by a plethora of stressors. Overall, we anticipate that this study will facilitate the development of innovative nanotechnology that leverages nanoparticle-corona complexes for ultra-sensitive and quick identification of diseases and stress in crops, accelerating agricultural productivity and meeting global food demands.