Nanomaterials (NMs) have the potential to revolutionize agriculture due to their unique properties. The high surface area to volume ratio of Copper (Cu)-based NMs makes them the ideal candidates to treat Cu deficient soils or fungal diseases in agriculture. However, the understanding of the possible adverse effects of Cu-based NMs on edible crops quality and ecosystems is very limited. Alfalfa (Medicago sativa L.) is an important plant in ecology, has nutritional value, and hyper-accumulates metals. This study was planned to evaluate the agronomical and molecular responses of alfalfa plants exposed to Cu NMs or other Cu compounds. Seeds of alfalfa (Mesa variety) were sown in potting soil amended with bulk Cu (bCu), nano Cu (nCu), and CuSO4 at 25 and 75 mg kg-1 and the plants were grown to full maturity. At harvest, the shoots and roots were washed with ddH2O, measured, weighted, and conserved at -80°C for further analysis. Soil samples were also taken for physicochemical and microbiological evaluations. Results showed that shoot fresh weight (g) was significantly increased by either nano or bulk treatments at both 25 or 75 mg kg-1 (2.33 g in average) compared to control (0.77 g in average) (p ≤ 0.05). The root fresh weight was significantly higher in all treatments, compared to control (p ≤ 0.05), except in plants exposed to CuSO4 at 25 mg kg-1. All treatments increased the shoot length, however, the nCu and bCu forms, at 25 mg kg-1, showed the highest increments against control (1.82-fold) (p ≤ 0.05). At 75 mg kg-1, the three Cu-based compounds significantly increased root length, compared with control (p ≤ 0.05). Data from RT-qPCR experiments to evaluate genes involved in the antioxidant response and metal acquisition will be examined. Additionally, the sample chemical element composition/concentration, and the relative abundance of microbial communities will also be discussed in this presentation. Taken together, these results will give important insights on the molecular and physiological responses of alfalfa plants exposed to different Cu sources. Moreover, this work will increase the knowledge about the possible implications of metallic Cu NMs onto the plant-microbiome interactions. This study aims to encourage the safe use of nano Cu compounds in agriculture.

Molecular and physiological responses of alfalfa (Medicago sativa) plants exposed to nano, bulk, and ionic copper compounds

2019 Fall National Meeting

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