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Effects of engineered nanomaterials on plant innate immune responses

Karl Effertz: Department of Plant Pathology, North Dakota State University

<div>Engineered nanomaterials (ENMs) have potential applications in agriculture including uses as pesticides and fertilizers. Plant-ENM interactions induce defense responses resulting in physiological reprogramming that can alter host-pathogen outcomes. Genetic resistance in barley line CI5791, effective against the necrotrophic fungal leaf pathogen <em>Pyrenophora teres f. teres</em> (<em>Ptt</em>), was compromised after root exposure to Zinc Oxide nanoparticles (ZnONPs). RNAseq analyses revealed spatial and temporal suppression of jasmonic acid (JA) responses, effective against necrotrophic pathogens and upregulation of salicylic acid responses effective against biotrophic pathogens, which are antagonistic to the JA responses. These transcriptome analyses may explain the compromised resistance observed. However, to understand the mechanisms by which plants recognize ENMs we developed a model where HvNDR1, a homolog of the <em>Arabidopsis</em> NDR1 gene, is part of a plasma membrane localized receptor complex which interacts with ENMs modulating host cell physiology that alter subsequent pathogen resistance mechanisms. We present data utilizing post-transcriptional gene silencing in barley and <em>Arabidopsis</em> mutants of the putative <em>Ndr1</em> complex components showing altered responses after nanoparticle treatment suggesting a role in ENM recognition and responses. Understanding plant-ENM interactions is essential for future development of ENMs for agricultural applications.</div>