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Stevia (Stevia rebaudiana Bertoni) is an important industrial crop, and its leaves contain steviol glycosides (SGs), which are valuable compounds because they are characterized by a high sweetness and low caloric content. SGs yield depends on nitrogen (N) nutrition; however, the role of N uptake in SGs synthesis needs clarification, especially in organic farming systems that depend on organic and biofertilizers. Plant growth-promoting bacteria (PGPB; i.e., Azospirillum brasilense and Bacillus circulans) and compost were used to study the effect of N nutrition on SGs yield. The experiment consisted of five N treatments with or without PGPB inoculation. The fertilization treatments were: C = without N, T 1 = urea, T 2 = compost, T 3 = urea and compost (75% of N from urea and the rest from compost) and T 4 = urea and compost (50% of N from urea and the rest 50% from compost). Compost and PGPB increased the soil quality indicators and enhanced the synthesis of chlorophyll and nutrient uptake by stevia plants. Mixtures of compost and urea under inoculation with PGPB enhanced soil microbes and enzymatic activity. The highest significant value of nitrogen use efficiency (NUE) resulted from urea alone, while the maximum phosphorus (P) and potassium (K) uptake came from compost. Although urea led to an increase in stevia N uptake, it led to a clear decrease in SGs yield. Urea decreased the total soluble sugar and leaf C/N ratio by 29% and 31%, respectively, compared to those of C. T 4 increased the SGs concentration by 74% and 46%, respectively, compared to that of urea alone in the presence and absence of PGPB. PGPB enhanced the soil quality and promoted nutrient uptake, resulting in significant increases in SGs yield. Regulating N uptake enhanced synthesis of soluble sugars and increased the C/N ratio, which caused an increase in SGs production. The use of compost and plant growth-promoting bacteria is a suitable strategy to produce stevia plants with low rates of inorganic nitrogen without any yield loss. [Display omitted] • Compost and plant growth-promoting bacteria (PGPB) enhances stevia growth. • Compost and PGPB reregulate N-uptake in stevia plants. • Urea decreased the total soluble sugar and leaf C/N ratio. • Regulating N-uptake increased the synthesis steviol glycosides (SGs). • The findings might be an aid for sustainable N management in stevia production. [ABSTRACT FROM AUTHOR]

The elevated level of CO 2 (eCO 2) and arbuscular mycorrhizal fungi (AMF) have been known as successful eco-friendly agents for plant growth and development as well as quality enhancers. The current investigation was designed to study the influence of eCO 2 (620 μmol CO 2 mol−1 air) and AMF on sucrose and phenylpropanoid metabolism, including coumarins, the most important bioactive metabolite in Ammi majus. eCO 2 and AMF were applied, and different parameters have been assessed in A. majus such as changes in mycorrhizal colonization, plant biomass production, photosynthesis, and levels of N, P, and Ca besides the key metabolites and enzymes in sucrose and coumarins metabolic pathways. The present outcomes revealed that eCO 2 and AMF individually or combined enhanced the plant biomass and photosynthesis as well as nutrient concentrations. Furthermore, the levels of sucrose, soluble sugars, glucose, fructose, and the activities of some key enzymes in their metabolism besides phenylpropanoids metabolites in shoot and root of A. majus have been enhanced by eCO 2 and AMF especially when combined. Moreover, upregulation of sucrose is linked to phenylpropanoids metabolic pathway via upregulation of phenylalanine ammonia-lyase activity suggesting high coumarin biosynthesis. Generally, the synergistic effect of both treatments was noted for most of the investigated parameters compared to the individual effect. It could be concluded that the combined application of eCO 2 and AMF affects A. majus global metabolism and induces accumulation of phyto-molecules, coumarin, which might improve its medicinal and pharmacological applications. • eCO 2 and AMF enhanced sucrose and PAL activity in A.majus therefore affects global metabolism and induces coumarin accumulation. [ABSTRACT FROM AUTHOR]

The prevalence of potentially toxic heavy metals (HMs)-bearing dust in the environment is posing serious health risks to humans. Therefore, the occurrence of HMs in indoor and outdoor dust samples of elementary school's environment in Riyadh, Saudi Arabia, were reported, and associated potential human health risks were estimated in this study. Dust samples were collected from outdoor and indoor environments from eighteen elementary schools using a soft plastic brush. The mean concentrations of Cd, Co, Cu, Ni, Pb, and Zn in collected indoor dust samples were much higher (0.08, 3.45, 59.20, 15.20, 4.99, and 94.10 mg kg−1, respectively) than that of outdoor dust samples (0.07, 3.07, 42.20, 13.60, 4.57, and 62.40 mg kg−1, respectively), due to fans operation, opened windows, and resuspension of dust by children's activities. The values of estimated enrichment factor revealed that both the outdoor and indoor dusts were moderately contaminated with Zn and Cu, while highly contaminated with Cd and Pb. However, the estimated potential ecological risks associated with HMs were lower. Health risks (non-carcinogenic and carcinogenic) calculations exhibited no potential risks of HMs in the schools' dust toward children. However, health risks for children were determined in the following order: up to 6 years > 6–12 years > adults. Therefore, assessing the potential health risks posed by HM-contaminated dust in school environments is necessary to avoid any possible children's health concerns. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) can promote plant growth and induce stress tolerance. Proline is reported to accumulate in mycorrhizal plants under stressful conditions, such as aluminum (Al) stress. However, the detailed changes induced in proline metabolism under AMF–plant symbiosis has not been studied. Accordingly, this work aimed to study how Al-stressed grass (barley) and legume (lotus) species respond to AMF inoculation at growth and biochemical levels. The associated changes in Al uptake and accumulation, the rate of photosynthesis, and the key enzymes and metabolites involved in proline biosynthesis and degradation pathways were studied. Soil contamination with Al induced Al accumulation in tissues of both species and, consequently, reduced plant growth and the rate of photosynthesis, while more tolerance was noticed in lotus. Inoculation with AMF significantly reduced Al accumulation and mitigated the negative impacts of Al on growth and photosynthesis in both species; however, these positive effects were more pronounced in barley plants. The mitigating action of AMF was associated with upregulation of proline biosynthesis through glutamate and ornithine pathways, more in lotus than in barley, and repression of its catabolism. The increased proline level in lotus was consistent with improved N metabolism (N level and nitrate reductase). Overall, this study suggests the role of AMF in mitigating Al stress, where regulation of proline metabolism is a worthy mechanism underlying this mitigating action. [ABSTRACT FROM AUTHOR]

In this work total column ozone (TCO) analysis and variability over globe has been studied during the period 1959–2022 using monthly mean data from ERA5 reanalysis database. The lower values of TCO occurs in equatorial latitudes, while the higher values of TCO appears over the mid-latitude and subpolar latitudes in both hemispheres (slightly farther poleward in the NH). The higher values of the coefficient of variation (CV) of TCO in NH and SH occur over the mid-latitude and subpolar latitudes, it increases gradually latitudinally poleward of 40°N. The lower values of CV appears over tropical and subtropical regions (between 40°S and 40°N). The trend study for the seasonal and annual spatial distribution of TCO divided the globe into three belts the trend values in the first belt (40°N- 90°N) are negative the trend values of TCO in the second belt (40°S- 40°N) are positive (increasing TCO). The third belt (40°S to 90°S) is characterized by the existence of negative trend values of TCO. The study of the Manne Whitney test for abrupt change of the time series of TCO for the three-time series of NHB confirms that there is abrupt change in TCO around the year 1971, 1979, 1992 (increasing) and 2013 (decreasing). • The higher values of TCO appear at mid-latitude and subpolar latitudes in both hemispheres. • The higher values of the coefficient of variation of TCO in NH and SH occur over the mid-latitudes and subpolar latitudes. • The lower values of the coefficient of variation of TCO appear in tropical and subtropical regions. • The trend study for the seasonal and annual TCO divided the globe into three belts. • The trend values in the first and third belts are negative, and positive in the second belt. [ABSTRACT FROM AUTHOR]

Recently, there has been considerable attention towards the production of environmentally friendly nanoparticles (NPs). In this investigation, the successful synthesis of cerium oxide nanoparticles (CeO 2 NPs) was achieved by employing an eco-friendly technique that utilized an extract from the leaves of local plant quinoa (Chenopodium quinoa L.). The synthesized CeO 2 NPs were subjected to characterization using state-of-the-art methods. The prepared CeO 2 NPs contained a round shape with clusters and have a size of 7–10 nm. To assess how effective CeO 2 NPs derived from C. quinoa were against Ustilago tritici , a fungal disease that negatively affects wheat crop globally, a study was performed on two varieties of wheat crop comprised of Arooj (V1) and Akber (V2), cultivated under field conditions. CeO 2 NPs were applied foliarly twice to the wheat crop at four different concentrations: T0 (0 mg/L), T1 (50 mg/L), T2 (75 mg/L), and T3 (100 mg/L). The results revealed that the control group (T0) exhibited the highest disease severity index (DSI) with a value of 75% compared to the other concentrations of CeO 2 NPs on both varieties. At a concentration of 100 mg/L of CeO 2 NPs, the DSI dropped to a minimum of 35% and 37% on both V1 and V2 respectively. These findings indicated that an increase in the concentration of CeO 2 NPs has a beneficial impact on disease severity. Similar patterns have also been observed with disease incidence (DI), with the greatest efficacy observed at a concentration of 100 mg/L of CeO 2 NPs. Our investigation has shown that CeO 2 NPs exhibitd significant antifungal potential against U. tritici which may be a promising strategy to mitigate fungal disease and crop losses globally. [Display omitted] • Chenopodium quinoa leaf extract was used to synthesie CeO 2 NPs • Antifungal potential of CeO 2 NPs was tested in field grown wheat plants • CeO 2 NPs exhibited significant antifungal activity against Ustilago tritici. • CeO 2 NPs could be a promising strategy to combat wheat fungal disease [ABSTRACT FROM AUTHOR]

The nutritional and health-promoting properties of plants are largely determined by their tissue chemistry. Tuning growth conditions could affect the accumulation of phytochemicals and, therefore, enhance the biological activities. Herein, the impact of elevated CO2 (eCO2; 620 µmol CO2 mol−1 air) on growth and chemical composition of sprouts of three Lepidium sativum cultivars (Haraz, Khider and Rajab) was investigated. Changes in the sprout actions against some human chronic diseases were evaluated. eCO2 induced biomass accumulation (1.46-, 1.47- and 2-fold in Haraz, Khider and Rajab, respectively) and pigment accumulation and reduced the level of antinutrients in L. sativum cultivars. Compared to the control, eCO2 induced total glucosinolate accumulation (0.40-, 0.90- and 1.29-fold in Khider, Haraz and Rajab, respectively), possibly through increased amino acid production, and their hydrolysis by myrosinase. In line with increased polyphenol production, improved phenylalanine ammonia lyase activity was observed. The antioxidant, anti-inflammatory, hypocholesterolemic, antibacterial and anticancer activities of the produced sprouts were significantly improved by sprouting and eCO2 exposure. PCA indicated that the cultivars showed interspecific responses. Thus, the present study confirms the synergistic effect of sprouting with eCO2 exposure as a promising approach to produce more bioactive L. sativum sprouts. [ABSTRACT FROM AUTHOR]

Desertification, the process of land degradation in arid, semi-arid, and dry sub-humid areas, poses significant environmental, social, and economic challenges worldwide. As desertification continues to threaten ecosystems and livelihoods, innovative strategies for its management are urgently needed. The article begins by elucidating the causes and consequences of desertification, emphasizing its complex interplay with human activities and natural factors. It highlights the growing recognition of soil microbes as a critical component in combatting desertification. Soil microbes, encompassing a diverse community of bacteria, fungi, archaea, and other microorganisms, play multifaceted roles in soil health, ecosystem function, and sustainable land management. This review delves into the mechanisms through which soil microbes can contribute to desertification management. It discusses their roles in nutrient cycling, soil fertility enhancement, carbon sequestration, soil stabilization, erosion control, and biodiversity conservation. Drawing on case studies and real-world examples, it offers insights into successful applications of soil microbe-based strategies across different geographical regions and ecosystems. Challenges and limitations in implementing these strategies are also examined, including factors such as environmental variability, scale of application, and potential risks. Furthermore, research gaps and areas for improvement in understanding the intricate relationships between soil microbes and desertification management are identified. The review explores prospects and research directions in soil microbe-based desertification management. It highlights innovative approaches, emerging technologies, and the importance of interdisciplinary collaboration. Additionally, it discusses policy implications and the potential of these strategies to contribute to sustainable land use practices. [ABSTRACT FROM AUTHOR]

Industrial activities have led to a gradual and global increase in soil aluminum (Al) and atmospheric CO 2 concentrations. Al bioavailability strongly depends on the soil pH, which in turn is affected by atmospheric CO 2 levels. In spite of the concurrent impact which Al and elevated CO 2 (eCO 2) could have on plants, their interaction and how it might affect the growth of economically important crop species has not been investigated. Here, we have investigated the combined impact of soil Al and eCO 2 exposure on key C3 (wheat, oat) and C4 (maize, sorghum) crops, at the physiological and biochemical level. Compared to C3 plants, C4 plants accumulated less Al by stimulating soil Al retention through exudation of root organic acids. Consequently, Al-exposed C4 plants maintained photosynthetic performance and anti-oxidative capacity. Exposure to eCO 2 reduced the stress responses of C3 and C4 crops to Al exposure. Elevated CO 2 decreased Al accumulation and oxidative damage in all cereals, and ameliorated C3 plant growth. This was reflected on the biochemical level, where eCO 2 inhibited ROS production and restored RuBisCo activity in C3 crops only. Overall, our data suggest that, compared to C3 crops, C4 cereals are more tolerant to soil Al exposure under current ambient CO 2 (aCO 2) levels whereas future eCO 2 levels might stimulate Al tolerance in C3 crops. [Display omitted] • Al differentially accumulated in C3 and C4. • Al differentially induced oxidative damage in C3 and C4. • eCO2 suppressed Al uptake and antagonized its phytotoxicity. • eCO2 inhibited ROS production and restored RuBisCo activity in C3 plants. • C4 plants appear more tolerant to soil Al exposure. [ABSTRACT FROM AUTHOR]

With the objective of studying the influence of elicitors on the growth, yield, and quality of kalmegh, we carried out an investigation for two consecutive years. Nine treatments with three replications were laid out in a completely randomized design (CRD). Chitosan (CHT), yeast extract (YE), jasmone acid (JA), and salicylic acid (SA)were evaluated at different concentrations. The CHT treatment at 1000 ppm exhibited the tallest plant height (73.91 cm) and the highest number of secondary branches (29.07) at the time of harvest. The primary branches and number of leaves per plant were highest with the CHT treatment at 1000 ppm (26.36; 88.32), and were not significantly different with the SA treatment at 200 ppm (26.28; 81.51). The plant spread was the highest with the SAtreatment at 200 ppm (35.46 cm2) and was not significantly different with the CHT treatment at 1000 ppm (35.11 cm2). The CHT and SA sprays did not result in significant changes in yield parameters, but the highest fresh (42.34 g) and dry (18.30) herbage yields per plant were exhibited with the SA treatment at 200 ppm. The highest total chlorophyll (4.459 mg g−1) and total andrographolide (3.494%) contents were recorded after treatment with the SA spray at 200 ppm. A significant and positive improvement in the growth, yield, and quality of kalmegh was noticed with the salicylic acid spray treatment at 200 ppm 30 and 60 days after sowing (DAS), signifying its benefits for the cultivation of kalmegh in terms of high productivity, quality, and better returns for farmers. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizae fungi (AMF) symbiosis is an indispensable approach in sustainable agriculture. AMF-plant association is likely to be enhanced by the nanoparticle's application. Herein, the impact of chitosan nanoparticles (CSNPs) on the mycorrhizal colonization in wheat has been investigated. The provoked changes in wheat growth, physiology and metabolism were assessed. CSNPs treatment improved AMF colonization (52 %) by inducing the levels of auxins and strigolactones in roots by 32 and 21 %, respectively besides flavonoids exudation into the rhizosphere (9 %). Such supporting action of CSNPs was associated with improved plant biomass production (21 %) compared to AMF treatment. Both treatments synergistically enhanced the photochemical efficiency of photosystem II and stomatal conductance, therefore the photosynthetic rate was increased. The combined application of CSNPs and AMF enhanced accumulation of glucose, fructose, sucrose, and starch (12, 22, 31 and 13 %, respectively), as well as the activities of sucrose-p-synthase, invertases and starch synthase compared to AMF treatment. The synchronous application of CSNPs and AMF promoted the levels of polyphenols, carotenoids, and tocopherols therefore, improved antioxidant capacity (33 %), in the roots. CSNPs can be applied as an efficient biofertilization strategies to enhance plant growth and fitness, beside improvement of health promoting compounds in wheat. [ABSTRACT FROM AUTHOR]

By the end of the twentieth century, the interest in natural compounds as probable sources of drugs has declined and was replaced by other strategies such as molecular target-based drug discovery. However, in the recent times, natural compounds regained their position as extremely important source drug leads. Indole-containing compounds are under clinical use which includes vinblastine and vincristine (anticancer), atevirdine (anti-HIV), yohimbine (erectile dysfunction), reserpine (antihypertension), ajmalicine (vascular disorders), ajmaline (anti-arrhythmic), vincamine (vasodilator), etc. Monoterpene Indole Alkaloids (MIAs) deserve the curiosity and attention of researchers due to their chemical diversity and biological activities. These compounds were considered as an impending source of drug-lead. In this review 444 compounds, were identified from six genera belonging to the family Apocynaceae, will be discussed. These genera (Alstonia, Rauvolfia, Kopsia, Ervatamia, and Tabernaemontana, and Rhazya) consist of 400 members and represent 20% of Apocynaceae species. Only 30 (7.5%) species were investigated, whereas the rest are promising to be investigated. Eleven bioactivities, including antibacterial, antifungal, anti-inflammatory and immunosuppressant activities, were reported. Whereas cytotoxic effect represents 47% of the reported activities. Convincingly, the genera selected in this review are a wealthy source for future anticancer drug lead. [ABSTRACT FROM AUTHOR]

Soil is considered an extensively explored ecological niche for microorganisms that produce useful biologically active natural products suitable for pharmaceutical applications. The current study aimed at investigating biological activities and metabolic profiles of three fungal strains identified from different desert sites in Saudi Arabia. Soil fungal isolates were collected from AlQasab, Tabuk, and Almuzahimiyah in Saudi Arabia and identified. Furthermore, their antibacterial activity was investigated against Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumonia, and Escherichia coli in blood, nutrient, and Sabouraud dextrose agars. Moreover, fungal extracts were evaluated on cell viability/proliferation against human breast carcinoma and colorectal adenocarcinoma cells. To identify the biomolecules of the fungal extracts, High-performance liquid chromatography HPLC–DAD coupled to analytical LC–QTOF-MS method was employed for fungal ethyl acetate crude extract. Identified fungal isolates, Chaetomium sp. Bipolaris sp. and Fusarium venenatum showed varied inhibitory activity against tested microbes in relation to crude extract, microbial strain tested, and growth media. F. venenatum showed higher anticancer activity compared to Chaetomium sp. and Bipolaris sp. extracts against four of the tested cancer cell lines. Screening by HPLC and LC/MS-QTOF identified nine compounds from Chaetomium sp. and three from Bipolaris sp. however, for F. venenatum extracts compounds were not fully identified. In light of the present findings, some biological activities of fungal extracts were approved in vitro, suggesting that such extracts could be a useful starting point to find compounds that possess promising agents for medical applications. Further investigations to identify exact biomolecules from F. venenatum extracts are needed. [ABSTRACT FROM AUTHOR]

Despite the wide utilization of chitosan nanoparticles (CSNPs) as a promising approach for sustainable agriculture, their efficiency under elevated CO 2 (eCO 2), has not been evaluated. The interactive effects of CSNPs and eCO 2 were evaluated on the growth and C and N metabolism of soybean plants. Plants were treated with CSNPs and grown under ambient CO 2 (410 ppm, aCO 2) or eCO 2 (645 ppm). Regardless of CO 2 level, CSNPs improved the net photosynthetic rate. CSNPs aggravated the effect of eCO 2 treatment on the levels of non-structural carbohydrates (i.e., glucose, fructose, sucrose, and starch), especially in shoots, which was inconsistence with the upregulation of carbohydrates metabolizing enzymes. Being the most pivotal energetic and signaling organic compounds in higher plants, the synergistic action of CSNPs and eCO 2 on the accumulation of soluble sugars upregulated the N metabolism as indicated by induced activities of nitrate reductase, arginase, glutamate dehydrogenase, glutamine synthetase, and glutamine oxoglutarate aminotransferase which was manifested finally as increased shoot and root total nitrogen content as well as proline and aspartate in roots. At the hormonal level, the coexistence of eCO 2 with CSNPs further supports their positive impact on the contents of IAA and, to a lesser extent, GAs. The present data prove that the biofertilization capacity of CSNPs is even more potent under futuristic eCO 2 levels and could even further improve the growth and resilience of plants. [ABSTRACT FROM AUTHOR]

Contamination of agricultural fields with bismuth (Bi) reduces crop yield and quality. Arbuscular mycorrhizal fungi (AMF) are known to enhance plant growth and crop production, even under stressful conditions such as soil contamination with heavy metals. The objective of this study was to investigate the effect of AMF on the mitigation of Bi-phytotoxicity in wheat (Triticum aestivum) and beans (Phaseolus vulgaris) and to provide a comprehensive evaluation of the physiological and biochemical basis for the growth and development of AMF-induced plants under Bi stress conditions. Wheat and bean were treated by Bi and AMF individually and in combination. Then the physiological and biochemical responses in the shoot and roots of the two crop species were studied. Evident retardations in plant growth and key photosynthesis-related parameters and accumulation of MDA, H 2 O 2 , as markers of oxidative stress, were observed in plants subjected to Bi. AMF colonization reduced the uptake and translocation of Bi in the plant organs by enhancing the exudation of polyphenols and organic acids into the rhizospheric soil. Mycorrhized wheat and bean plants were able to attenuate the effects of Bi by improving metal detoxification (phytochelatins, metallothionein, total glutathione, and glutathione-S-transferase activity) and antioxidant defense systems (both enzymatic and non-enzymatic) and maintaining C assimilation and nutrient status. The current results suggest the manipulation of AMF as a powerful approach to alleviate the phytotoxicity of Bi in legumes and grasses. • Arbuscular mycorrhizal fungi (AMF) stimulate bean, and wheat responses to bismuth (Bi) and alleviate its phytotoxicity. • AMF colonization on wheat and bean reduced Bi uptake by enhancing the exudation of polyphenols and organic acids into the rhizosphere. • AMF colonization improved plant metal detoxification, antioxidant defense systems and maintaining C assimilation and nutrient status. • AMF colonization was more effective in bean than in wheat, as evidenced by lower Bi uptake in bean indicating the influence of plant species in response to stress conditions. [ABSTRACT FROM AUTHOR]

Powdery mildew in cucumber is caused by the Podosphaera xanthii. No strategy for improving disease resistance can be successful in the absence of thorough insights into the physiological and biochemical responses of cucumber plants to powdery mildew. Therefore, a field experiment was executed to evaluate five commercial cucumber varieties (V 1 : Dynasty, V 2 : Long green, V 3 :Desi Kheera, V 4 :Thamin II, V 5 :Cucumber 363) for their inherent immunity to powdery mildew. Upon inoculating cucumber plants with Podosphaera xanthii , we noted differential responses among the varieties. Compared to other varieties, V 1 and V 2 showed higher values (P ≤ 0.05) for chlorophyll-a under control and pathogen-attacked plants respectively. The minimum value of anthocyanin content (−53.73%) was recorded in V 3 as compared to other varieties post pathogen infection. All pathogen-infected cucumber varieties showed a considerable (P ≤ 0.05) loss in flavonoid content except V 2. The maximum destruction for Phenolics under powdery mildew (179%) were recorded in V 4 , whereas V 1 exhibited maximum phenolic content under control conditions. In pathogen-infected plants, the minimum AsA was recorded in V 5 as compared to all other varieties. Pathogen invasion impacted significantly (P ≤ 0.05) the activity of superoxide dismutase (SOD). Besides, cucumber plants after pathogen inoculation resulted in a considerable (P ≤ 0.05) increase of peroxidase (POD) activity in V 1 (5.02%), V 2 (7.5%), and V 3 (11%) in contrast to V 4. Our results confirmed that cucumber varieties perform differently, which was brought on by distinct metabolic and physiological modifications that have an impact on growth and development. The changes in different attributes were correlated with cucumber resistance against powdery mildew. The results would help us fully harness the potential of these varieties to trigger disease management initiatives and defense responses. • Powdery mildew disease in cucumber is pervasive and devastating. • Control of powdery mildew needs improved resistance in cucumber. • We estimated physio-biochemical responses of cucumber for immunity to powdery mildew. • Cucumber varieties performed differently by distinct metabolic modifications. • Different attributes were correlated with cucumber resistance to powdery mildew. [ABSTRACT FROM AUTHOR]

Future climate CO 2 (eCO 2) and contamination with nano-sized heavy metals (HM-NPs) represent concurrent challenges threatening plants. The interaction between eCO 2 and HM-NPs is rarely investigated, and no study has addressed their synchronous impact on the metabolism of the multifunctional stress-related metabolites, such as sugars and amino acids. Moreover, the characteristic responses of C3 and C4 plant systems to the concurrent impact of eCO 2 and HM-NPs are poorly understood. Herein, we have assessed the impact of eCO 2 (620 ppm) and/or HgO-NPs (100 mg/Kg soil) on growth, physiology and metabolism of sugars and amino acids, particularly proline, in C3 (wheat) and C4 (maize) plant systems. Under Hg-free conditions, eCO 2 treatment markedly improved the growth and photosynthesis and induced sugars levels and metabolism (glucose, fructose, sucrose, starch, sucrose P synthase and starch synthase) in wheat (C3) only. In contrast, HgO-NPs induced the uptake, accumulation and translocation of Hg in wheat and to less extend in maize plants. Particularly in wheat, this induced significant decreases in growth and photosynthesis and increases in photorespiration, dark respiration and levels of tricarboxylic acid cycle organic acids. Interestingly, the co-application of eCO 2 reduced the accumulation of Hg and recovered the HgO-NPs-induced effects on growth and metabolism in both plants. At stress defense level, HgO-NPs induced the accumulation of sucrose and proline, more in maize, via upregulation of sucrose P synthase, ornithine amino transferase, ∆1-pyrroline-5-carboxylate (P5C) synthetase and P5C reductase. The co-existence of eCO 2 favored reduced sucrose biosynthesis and induced proline catabolism, which provide high energy to resume plant growth. Overall, despite the difference in their response to eCO 2 under normal conditions, eCO 2 induced similar metabolic events in C3 and C4 plants under stressful conditions, which trigger stress recovery. Unlabelled Image • Under HgO-NPs free conditions, the biofertilization impact of eCO 2 is only evident in wheat (C3). • HgO-NPs increased Hg uptake, accumulation and translocation in the tested plants. • Maize plants (C4) were more tolerant to HgO-NPs toxicity than wheat. • HgO-NPs induced the accumulation of sucrose and proline, more in maize. • Coexistence of eCO 2 with HgO-NPs reduced sucrose biosynthesis and induced proline catabolism in both plants. [ABSTRACT FROM AUTHOR]

Chromium (Cr) contamination reduces crop productivity worldwide. On the other hand, the expected increase in the future CO 2 levels (eCO 2) would improve plant growth under diverse growth conditions. However, the synergetic effect of eCO 2 has not been investigated at both physiological and biochemical levels in Cr-contaminated soil. This study aims to analyze the mitigating effect of eCO 2 on Cr VI phytotoxicity in two rice cultivars (Giza 181 and Sakha 106). Plants are exposed to different Cr concentrations (0, 200 and 400 mg Cr/kg Soil) at ambient (aCO 2) and eCO 2 (410 and 620 ppm, respectively). Unlike the stress parameters (MDA, H2O2 and protein oxidation), growth and photosynthetic reactions significantly dropped with increasing Cr concentration. However, in eCO 2 conditions, plants were able to mitigate the Cr stress by inducing antioxidants as well as higher concentrations of phytochelatins to detoxify Cr. Notably, the expression levels of the genes involved in mineral nutrition i.e., OsNRAMP1 , OsRT1 , OsHMA3 , OsLCT1 and iron chelate reductase were upregulated in Cr-stressed Giza 181 plants grown under eCO 2. Mainly in Sakha 106, eCO 2 induced ascorbate-glutathione (ASC/GSH)-mediated antioxidative defense system. The present study brings the first ever comprehensive assessment of how future eCO 2 differentially mitigated Cr toxicity in rice. [Display omitted] • Cr exposure induces severe oxidative damage and dysregulates mineral homeostasis. • ECO 2 upregulates the expression of mineral transporter genes in Cr-stressed plants. • ECO 2 modulates the antioxidant defense and metal detoxification systems. • Cultivar-specific responses to the coexistence of Cr and eCO 2 will be noticed. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) are beneficial for the plant growth under heavy metal stress. Such beneficial effect is improved by elevated CO 2 (eCO 2). However, the mechanisms by which eCO 2 improves AMF symbiotic associations under arsenite (AsIII) toxicity are hardly studied. Herein, we compared these regulatory mechanisms in species from two agronomical important plant families – grasses (wheat) and legumes (soybean). AsIII decreased plant growth (i.e., 53.75 and 60.29% of wheat and soybean, respectively) and photosynthesis. It also increased photorespiration and oxidative injury in both species, but soybean was more sensitive to oxidative stress as indicated by higher H 2 O 2 accumulation and oxidation of protein and lipid. eCO 2 significantly improved AMF colonization by increasing auxin levels, which induced high carotenoid cleavage dioxygenase (CCDs) activity, particularly in soybean roots. The improved sugar metabolism in plant shoots by co-application of eCO 2 and AsIII allocated more sugars to roots sequentially. Sugar accumulation in plant roots is further induced by AMF, resulting in more C skeletons to produce organic acids, which are effectively exudated into the soil to reduce AsIII uptake. Exposure to eCO 2 reduced oxidative damage and this mitigation was stronger in soybean. This could be attributed to a greater reduction in photorespiration as well as a stronger antioxidant and detoxification defence systems. The grass/legume-specificity was supported by principal component analysis, which revealed that soybean was more affected by AsIII stress and more responsive to AMF and eCO 2. This study provided a mechanistic understanding of the impact of AMF, eCO 2 and their interaction on As-stressed grass and legume plants, allowing better practical strategies to mitigate AsIII phytotoxicity. [Display omitted] • Soybean was more sensitive to As stress but more reponsive to AMF and eCO 2 impact. • High strigolactone biosynthesis by eCO 2 induced AMF colonization, mainly in soybean. • Increased photosynthesis by eCO 2 allocated more sugars to AMF roots of soybean and wheat. • eCO 2 increased soil retention resulting in less As accumulation in AMF treated plants. • eCO 2 strengthen AMF impact on decreasing ROS production and increasing their detoxification. [ABSTRACT FROM AUTHOR]

The broad application of metal nanoparticles in different fields encourages scientists to find alternatives to conventional synthesis methods to reduce negative environmental impacts. Herein, we described a safe method for preparing silver nanoparticles (J-AgNPs) using Jatropha integerrima leaves extract as a reducing agent and further characterize its physiochemical and pharmacological properties to identify its therapeutic potential as a cytotoxic and antimicrobial agent. The biogenic synthesized J-AgNPs were physiochemically characterized by ultraviolet-visible spectroscopy, dynamic light scattering (DLS), transmission electron microscope (TEM), and energy-dispersive X-ray spectroscopy. HPLC-DAD, followed by LC/MS and the Fourier-transform infrared spectroscopy (FTIR), was applied to detect the biomolecules of J. integerrima involved in the fabrication of NPs. Furthermore, J-AgNPs and the ampicillin-nanocomposite conjugate were investigated for their potential antibacterial effects against four clinical isolates. Finally, cytotoxic effects were also investigated against cancer and normal cell lines, and their mechanism was assessed using TEM analysis and confocal laser scanning microscopy (LSM). Ag ions were reduced to spherical J-AgNPs, with a zeta potential of −34.7 mV as well as an average size of 91.2 and 22.8 nm as detected by DLS and TEM, respectively. HPLC GC/MC analysis identified five biomolecules, and FTIR suggested the presence of proteins besides polyphenolic molecules; together, these molecules could be responsible for the reduction and capping processes during NP formation. Additionally, J-AgNPs displayed a strong antibacterial effect, although the ampicillin conjugated form had a very weak antibacterial effect. Furthermore, the NPs caused a reduction in cell viability of all the treated cells by initiating ultrastructural changes and apoptosis, as identified by TEM and LSM analysis. Therefore, J-AgNPs can be formed using the leaf extract from the J. integerrima plant. Furthermore, J-AgNPs may serve as a candidate for further biochemical and pharmacological testing to identify its therapeutic value. [ABSTRACT FROM AUTHOR]