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Artemisinin is a sesquiterpene lactone endoperoxide, recognized for its application as a treatment for malaria. Besides, it has activity against several types of cancers, as well as anti-viral and anti-inflammatory properties. The chemical synthesis of artemisinin is quite complex and economically unfeasible. Hence, artemisinin is typically obtained from Artemisia annua plants in low quantities in relation to the biomass. A strategy to increase the biosynthesis of secondary metabolites would be the application of elicitors. In this work, the effect of treating A. annua plants with menadione sodium bisulphite (MSB) is studied. An initial dose-optimization was conducted by treating the plants with different MBS concentrations (0, 0.2, 0.8, 1, 2, 3 and 4 mM) and artemisinin was quantified 48 h after treatment. The highest artemisinin content (3.71 mg artemisinin g−1 DW) was obtained with 1 mM of MSB. Then, harvesting time was optimised (24, 48 and 72 h after treatment application) with 1 mM of MSB. The largest increase in artemisinin content was observed at 48 h with an increment of 62.37 % over the control. The treatment increased H2O2 content, as well as the activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX). Besides, MSB up-regulated HMGR (the gene for 3-hydroxy-3-methylglutaryl-CoA reductase) and DXS (the gene for 1-deoxy-D-xylulose-5-phosphate synthase) 24 h after treatment. Both genes are involved in the MVA (mevalonate) and MEP (2C-methylerythritol 4-phosphate) pathways, respectively. These pathways represent the initiation of artemisinin biosynthesis. Thus, MSB application and the consequent up-regulation of early biosynthetic pathway genes along with the triggered oxidative stress may have been contributed to the observed increase in artemisinin production.

Climate change has increased the severity of drought episodes by further reducing precipitation in vulnerable zones. Drought induces a substantial decrease in agricultural water, reducing crop yields. Consequently, addressing water consumption can increase farmers’ profits. This work describes lab-to-field research in Zea mays, using two biostimulants: glycine betaine (GB) and Lpyroglutamic acid (PG). The biostimulant optimal dosages were selected using a hydroponic system with 20% polyethylene glycol and nursery experiments under water-deficit irrigation. The established dosages were evaluated in field trials in which irrigation was reduced by 20%. Laboratory biostimulant optimisation showed in stressed treated seedlings (GB 0.1 mM; PG 1 mM) an increased dry weight, relative growth rate and water use efficiency, reducing seedling growth loss between 65 and 85%, respectively. Field trials using a GB-optimised dosage showed an increase in plants’ growth, grain yield and flour Ca content. In addition, grain flour carbohydrate content and protein remained similar to control well-watered plants. Finally, the economic aspects of biostimulant treatments, water consumption, water sources (ground vs. desalinated) and grain biomass were addressed. Overall, GB treatment demonstrated to be a valuable tool to reduce water consumption and improve farmers’ earnings.

Among its other effects, climate change is driving humanity into water scarcity, especially in highly populated areas such as the Mediterranean. One of the best options to solve this problem is seawater desalination, but it has its environmental, social and economic impacts. The brine reject effluent from the process can be used as a rich mineral source for hydroponic culture. Indeed, stability in its composition was shown here during a one-year study. A compilation of analyses from desalination facilities located worldwide also demonstrates how reutilisation of this liquid waste can provide an opportunity to build a circular economy based on brine management. Potential profitable crops and an economic study of its implementation are discussed. Correct brine management channelled into an agricultural context can be an excellent way to improve the public and ecological reputation of desalination. It can also yield extra income beyond the fresh water yield from the proposed system.

Introduction: Artemisinin is a secondary metabolite well-known for its use in the treatment of malaria. It also displays other antimicrobial activities which further increase its interest. At present, Artemisia annua is the sole commercial source of the substance, and its production is limited, leading to a global deficit in supply. Furthermore, the cultivation of A. annua is being threatened by climate change. Specifically, drought stress is a major concern for plant development and productivity, but, on the other hand, moderate stress levels can elicit the production of secondary metabolites, with a putative synergistic interaction with elicitors such as chitosan oligosaccharides (COS). Therefore, the development of strategies to increase yield has prompted much interest. With this aim, the effects on artemisinin production under drought stress and treatment with COS, as well as physiological changes in A. annua plants are presented in this study. Methods: Plants were separated into two groups, well-watered (WW) and drought-stressed (DS) plants, and in each group, four concentrations of COS were applied (0, 50,100 and 200 mg•L-1). Afterwards, water stress was imposed by withholding irrigation for 9 days. Results: Therefore, when A. annua was well watered, COS did not improve plant growth, and the upregulation of antioxidant enzymes hindered the production of artemisinin. On the other hand, during drought stress, COS treatment did not alleviate the decline in growth at any concentration tested. However, higher doses improved the water status since leaf water potential (YL) improved by 50.64% and relative water content (RWC) by 33.84% compared to DS plants without COS treatment. Moreover, the combination of COS and drought stress caused damage to the plant’s antioxidant enzyme defence, particularly APX and GR, and reduced the amount of phenols and flavonoids. This resulted in increased ROS production and enhanced artemisinin content by 34.40% in DS plants treated wi

The commercial production of artemisinin and other valuable bioactive natural products depends on their plant sources, which may provide variable amounts of the compound depending on plant variety, the period of the year, abiotic stress and other factors. Therefore, it requires a method for large-scale, low-cost natural product quantification. The standard HPLC and UHPLC methods are accurate but the analysis are costly and require different optimization for structurally-diverse products. An alternative method using NMR with TBS-pyrrole as a novel “universal” reference affords a simple, fast method to quantify many different products. The method is shown with antimalarial artemisinin, whose yield using conventional and novel extraction procedures was determined by standard UHPLC-MS procedures and by our NMR protocol, with similar quantification results. The novel reference compound does not interfere with artemisinin or extract signals, only needs a small amount of the extract, is accurate and operationally simple, and a large volume of samples can be processed in little time. Moreover, bioactive terpenes, steroids, alkaloids, aromatic compounds, and quinones, among others, were quantified in a model vegetal extract with this “universal” reference with excellent accuracy.

Water is indispensable for the life of any organism on Earth. Consequently, osmotic stress due to salinity and drought is the greatest threat to crop productivity. Ongoing climate change includes rising temperatures and less precipitation over large areas of the planet. This is leading to increased vulnerability to the drought conditions that habitually threaten food security in many countries. Such a scenario poses a daunting challenge for scientists: the search for innovative solutions to save water and cultivate under water deficit. A search for formulations including biostimulants capable of improving tolerance to this stress is a promising specific approach. This review updates the most recent state of the art in the field.

BACKGROUND Botrytis cinerea, the causal agent of gray mold has a great economic impact on several important crops. This necrotrophic fungus causes disease symptoms during vegetative growth and also into postharvest stages. The current method to combat this disease is fungicide application, with high economic costs and environmentally unsustainable impacts. Moreover, there is an increasing general public health concern about these strategies of crop protection. We studied the protection of tomato plants against B. cinerea by previous root treatment with menadione sodium bisulfite (MSB), a known plant defense activator. RESULTS Root treatment 48 h before inoculation with MSB 0.6 mmol L−1 reduced leaf lesion diameter by 30% and notably cell deaths, compared to control plants 72 h after inoculation. We studied the expression level of several pathogenesis-related (PR) genes from different defense transduction pathways, and found that MSB primes higher PR1 expression against B. cinerea. However, this stronger induced resistance was impaired in transgenic salicylic acid-deficient NahG line. Additionally, in the absence of pathogen challenge, MSB increased tomato plant growth by 28% after 10 days. Our data provide evidence that MSB protects tomato plants against B. cinerea by priming defense responses through the salicylic acid (SA)-dependent signaling pathway and reducing oxidative stress. CONCLUSION This work confirms the efficacy of MSB as plant defense activator against B. cinerea and presents a novel alternative to combat gray mold in important crops.

Biostimulants (BSs) are probably one of the most promising alternatives nowadays to cope with yield losses caused by plant stress, which are intensified by climatechange. Biostimulants comprise many different compounds with positive effects on plants, excluding pesticides and chemical fertilisers. Usually mixtures such as lixiviates from proteins or algal extracts have been used, but currently companies are interested in more specific compounds that are capable of increasing tolerance against abiotic stress. Individual application of a pure active compound offers researchers the opportunity to better standarise formulations, learn more about the plant defence process itself and assist the agrochemical industry in the development of new products. This review attempts to summarise the state of the art regarding various families of organic compounds and their mode/mechanism of action as BSs, and how they can help maximise agricultural yields under stress conditions aggravated by climate change.

For >50 years the Canary Islands have been using seawater desalinization facilities in order to satisfy the freshwater demand of their main economic activity –tourism, which continues to contribute to the economic and social progress of the archipelago. However, this desalinization process involves the production of a “waste” product known as rejected brine, which is discharged from coastal regions and islands, whether it originates from public or private facilities. Rejected brines are potentially a serious threat to marine ecosystems. However, here we demonstrate that this “waste” can be processed and reused as a nutrient mineral solution for a hydroponic production system and also a source of freshwater. The efficiency of this management process in terms of fresh-water production and water recycling economy is also discussed. The aim of this paper is to change the attitude towards rejected brines, which should be treated as potential raw material to permit high savings in the running costs of leisure and tourist facilities around the archipelago. In addition, this will also have a positive effect on the environment, making desalinization more sustainable and environmentally friendly, which is nowadays an added value in customer and user satisfaction.