Pharmaceuticals in treated wastewater induce a stress response in tomato plants

Abstract

Pharmaceuticals remain in treated wastewater used to irrigate agricultural crops. Their effect on terrestrial plants is practically unknown. Here we tested whether these compounds can be considered as plant stress inducers. Several features characterize the general stress response in plants: production of reactive oxygen species acting as stress-response signals, MApKs signaling cascade inducing expression of defense genes, heat shock proteins preventing protein denaturation and degradation, and amino acids playing signaling roles and involved in osmoregulation. tomato seedlings bathing in a cocktail of pharmaceuticals (carbamazepine, Valporic acid, phenytoin, Diazepam, Lamotrigine) or in Carbamazepine alone, at different concentrations and during different time-periods, were used to study the patterns of stress-related markers. the accumulation of the stress-related biomarkers in leaf and root tissues pointed to a cumulative stress response, mobilizing the cell protection machinery to avoid metabolic modifications and to restore homeostasis. The described approach is suitable for the investigation of stress response of different crop plants to various contaminants present in treated wastewater. Expanding populations aggravates the demand for freshwater for human consumption, agriculture and industry. While the sources of freshwater are limited and often polluted, reclaimed wastewater offers an additional resource that could be used to irrigate crops in agricultural systems. However, only 1% of the water used for irrigation worldwide consists of treated wastewater. Several countries use reclaimed wastewater for crop irrigation. For example, Israel uses 85% of the treated wastewater for irrigation, over half of the total irrigation volume 1. However, the current water purification devices are unable to eliminate some pharmaceuticals used by humans for personal care and medicine, released in the sewage. With the growing use of treated wastewater for irrigation, increasing amounts of these products find their way in the agroecosystem 2. The fate of these pollutants on soils and on plants 3 , and the potential risks for humans ingesting the plant edible parts (from infants to pregnant women and seniors) are under scrutiny 4-6. Therefore, the use of treated wastewater in the EU could be regulated in the near future 7. Psychoactive drugs are a major class of pharmaceuticals still found after wastewater treatment 8,9. They originate from excretion by patients, discarded medications or pharmaceutical industry effluents. Among them, Carbamazepine (CBZ) is one of the most abundant. This drug is used to treat epilepsy and trigeminal neuralgia. Low removal efficiency and minimal degradability of CBZ and its metabolites have been reported 10,11. CBZ is detected in influent and effluent wastewater in municipal wastewater-treatment plants in many countries 10,12-14. For example, in the city of Peterbourg, ON, Canada, the concentration of CBZ and its derivatives was about 460 ng/l in the untreated wastewater and 440 ng/l after t...

Interplay between abiotic (drought) and biotic (virus) stresses in tomato plants

“…In response to withholding water, plants accumulate not only carbohydrate metabolites, but also amino acids (Krasensky & Jonak, 2012). The patterns of several osmoprotective amino acids shown previously to be involved in tomato stress response to abiotic stresses (Gorovits et al, 2020) were notable in plants subjected to drought. Indeed, drought strongly induced several selected amino acids (Figure 4 and Figure S1).…”

Physiological and Biochemical Parameters of Common Duckweed Lemna minor after the Exposure to Tetracycline and the Recovery from This Stress

“…The HSP 70 protein content in these samples was 51.86 and 48.71 ng × mL −1 , respectively (131 and 123% increase, compared with the control). Gorovits et al [69] also showed an increase in HSP 70 content in tomato leaves treated with pharmaceuticals, in the concentration range of 10-100 µg × L −1 . Even the lowest concentration of pharmaceuticals (10 µg × L −1 ) induced HSP 70 proteins in leaves.…”

Plant pharmacology: Insights into in-planta kinetic and dynamic processes of xenobiotics

“…Recent studies suggest that pharmaceuticals, similar to low doses of herbicides, may have a negative impact on plant development and agricultural production (Bigott et al, 2021;Carter et al, 2015;Christou et al, 2016;Gorovits et al, 2020Gorovits et al, , 2021. For example, plant exposure to carbamazepine has indicated an effect on plant development, with changes in nutrient and plant hormone concentrations, interference of cell signaling and plant defense and changes in amino acid concentrations and additional osmo-protectants accumulation (Carter et al, 2015;Gorovits et al, 2020Gorovits et al, , 2021. Several studies have also demonstrated that plant exposure to pharmaceuticals may result in changes in the expression of stress related genes (Bigott et al, 2021;Christou et al, 2016).…”

“…The determination of plant pharmacodynamic biomarkers aims to characterize the exposure or time dependent response of a plant upon exposure to xenobiotic compounds. Biomarker categories include predictive biomarkers which measure any general response/lack of response, or mechanism-of-action biomarkers that allow insights into the pharmacodynamic effects of a drug as well as insight into cellular or sub-cellular responses (Carter et al, 2015;Garralda et al, 2017;Gorovits et al, 2020Gorovits et al, , 2021. Plant pharmacology proposes the establishment of plant pharmacodynamic biomarkers that expand beyond the traditional morphological variations and biochemical changes in plants.…”