Heliotropium L. genus belongs to the Boraginaceae family and is represented by approximately 250 species found in the temperate warm regions of the world, and there are 15 species of these species recorded in Turkiye. Heliotropium hirsutissimum Grauer grows in Bulgaria, Greece, N. Africa, Syria, and Turkiye. There is no record showing that H. hirsutissimum is a heat-tolerant plant. However, in our field studies, it was observed that H. hirsutissimum, which is also distributed in Hisaralan Thermal Springs of Sindirgi-Balikesir, Turkiye, grows in the thermal area with extremely high soil temperature (57.6 degrees C (similar to 60 degrees C)). It was thought that it would be useful to investigate the tolerance mechanism of the H. hirsutissimum plant to extremely high temperatures. For this purpose, the plant seeds were obtained from a geothermal area in the thermal spring. Growing plants were exposed to 20, 40, 60, and 80 +/- 5 degrees C soil temperature gradually for 15 days under laboratory conditions. We measured the effect of high soil temperature on some morphological changes, relative water content, thiobarbituric acid reactive substances, cell membrane stability, and hydrogen peroxide analysis to determine stress levels on leaves and roots. Changes in osmolyte compounds, some antioxidant enzyme activities, ascorbate content, and chlorophyll fluorescence and photosynthetic gas exchange parameters were also determined. As a result of the study carried out to determine the stress level, it was observed that there was not much change and it was understood that the plant was tolerant to high soil temperature. In addition, there was a general increase in osmolytes accumulation, antioxidant enzyme activities, and ascorbate level. There was no significant difference in photosynthetic gas exchange and chlorophyll fluorescence parameters of plants grown at different soil temperatures. The high temperature did not negatively impact the photosynthetic yield of H. hirsutissimum because this plant was found to enhance its antioxidant capacity. The increase in antioxidant activity helped reduce oxidative damage and protect the photosynthetic mechanism under high temperature conditions, while the significant increase in the osmolyte level helped maintain the water status and cell membrane integrity of plants, thus enabling them to effectively withstand high soil temperatures.

Fusarium graminearum poses a major threat to barley production worldwide. While seed priming is a promising strategy to enhance plant defense, the use of unconventional priming agents remains underexplored. This study investigates the protective effects of pre-infection camel urine seed priming on barley seedlings challenged with Fusarium graminearum, focusing on growth, disease resistance, oxidative stress, and defense-related responses. Barley grains were primed with camel urine and grown in both Fusarium-infested and uninfested soils. Fusarium infection initially triggered a sharp increase in oxidative stress markers reflecting an early oxidative burst commonly associated with defense signaling. However, in hydro-primed seedlings, this response persisted, leading to sustained oxidative damage and growth suppression. In contrast, camel urine priming modulated the oxidative burst effectively, initially permitting H2O2 accumulation for defense activation, followed by a rapid decline, resulting in an 84.53 % reduction in disease severity and maintenance of seedling growth under infection. This was accompanied by enhanced antioxidant defenses, as indicated by significantly increased activities of antioxidant enzymes, and a 145 % increase in total antioxidant capacity compared to control. Camel urine priming also showed a reduction in shikimic acid levels under infection, suggesting increased metabolic flux toward the phenylpropanoid pathway. Thus, phenylalanine ammonia-lyase activity, phenolic compounds, and flavonoids were significantly elevated. Antifungal enzymes, beta-glucanase and chitinase, also remained high in camel urine-primed seedlings, in contrast to their sharp decline in hydro-primed controls. These findings highlight camel urine priming as a promising, sustainable approach for managing Fusarium in barley.

Cadmium (Cd) is a major soil pollutant that threatens plant growth and human health. The plant ATPase associated with various cellular activities (AAA) SKD1 utilizes ATP hydrolysis energy to mediate cellular responses to environmental stress. However, the role and regulatory mechanisms of SKD1 in plant responses to Cd stress are not well understood. This study has demonstrated that the maize SKD1 gene (ZmSKD1) enhanced tobacco's tolerance to Cd stress. Overexpression of ZmSKD1 in tobacco reduced Cd accumulation and improved Cd tolerance. Moreover, ZmSKD1 overexpression enhanced the antioxidant capacity of tobacco, maintaining reactive oxygen species homeostasis and mitigating oxidative damage under Cd stress. The transcription factor AGL8 directly activated ZmSKD1 transcription, which in turn boosted ATPase activity in tobacco. This activation enhanced vesicle trafficking in root cells and accelerated Cd excretion in transgenic tobacco plants. Concurrently, the AGL8-ZmSKD1 module inhibited the expression of several Cd transport-related genes, thereby reducing Cd uptake by tobacco roots. These findings identified the AGL8-ZmSKD1 module as a crucial player in managing Cd stress through the vesicle trafficking pathway, offering valuable insights into strategies for developing crops with reduced Cd accumulation to ensure global food security and human health.

The use of plant growth promoting rhizobacteria (PGPRs) to improve crop growth under salt stress is gaining attention in recent years. In this study, we evaluated the potential of Bacillus amyloliquefaciens strain Q1 to mitigate salt stress in barley. Barley seedlings were inoculated without (-) or with (+) Q1 and then subjected to four salt levels (0-320 mM) to assess the changes in plant growth, photosynthetic attributes, ion homeostasis, and antioxidant capacity. Our results revealed that the slight salt stress (80 mM) caused little damage to plant growth and physiological processes of barley seedlings, indicating the potential of barley for crop production in saline soils equal to or less than this salt level. However, the moderate (160 mM)- or severe (320 mM)-level salt stress considerably reduced the plant growth of barley seedlings, because of the inhibition of photosynthetic capacity and disruption of Na+/K+ homeostasis. The inoculation with Q1 notably ameliorated these detrimental effects of salt stress, and its efficacy was more predominant at the severe salt level. Moreover, Q1 significantly enhanced the activities of antioxidant enzymes in barley at the severe salt level, but not at the slight or moderate salt level. Taken together, it is concluded that Q1 has limited promoting effect on barley under the normal growth condition, whereas it is capable to help barley maintain much better growth and performance under salt stress, especially at the severe level. Our study has expanded the list of PGPR resources for sustainable utilization of saline land.

Microbial secondary metabolites are crucial in plant-microorganism interactions, regulating plant growth and stress responses. In this study, we found that cyclo(-Phe-Pro), a proline-based cyclic dipeptide secreted by many microorganisms, alleviated aluminum toxicity in wheat roots by increasing root growth, decreasing callose deposition, and decreasing Al accumulation. Cyclo(-Phe-Pro) also significantly reduced Al-induced reactive oxygen species (ROS) with H2O2, O2 center dot-, and center dot OH levels decreasing by 19.1%, 42.8%, and 17.9% in root tips, thus protecting the plasma membrane from oxidative damage. Although Al stress increased the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) in wheat roots, cyclo (-Phe-Pro) application reduced these enzyme activities. However, compared to the Al treatment, cyclo(-Phe-Pro) application increased DPPH and FRAP activities by 16.8% and 14.9%, indicating increased non-enzymatic antioxidant capacity in wheat roots. We observed that Al caused the oxidation of ascorbate (AsA) and glutathione (GSH) to dehydroascorbate (DHA) and glutathione disulfide (GSSG), respectively. Under Al stress, cyclo (-Phe-Pro) treatment maintained reduced AsA and GSH levels, as well as high AsA/DHA and GSH/GSSG redox pair ratios in wheat roots. High AsA/DHA and GSH/GSSG ratios can reduce Al toxicity by neutralizing free radicals and restoring redox homeostasis via antioxidant properties. These results suggest that cyclo(-Phe-Pro) maintains ASA- and GSH-dependent redox homeostasis to alleviate oxidative and Al stress in wheat roots. Findings of this study establishes a theoretical foundation for using microbial metabolites to mitigate Al toxicity in acidic soils, highlighting their potential in sustainable agriculture.

The increasing frequency of low-temperature events in spring, driven by climate change, poses a serious threat to wheat production in Northern China. Understanding how low-temperature stress affects wheat yield and its components under varying moisture conditions, and exploring the role of irrigation before exposure to low temperatures, is crucial for food security and mitigating agricultural losses. In this study, four wheat cultivars-semi-spring (YZ4110, LK198) and semi-winter (ZM366, FDC21)-were tested across two years under different conditions of soil moisture (irrigation before low-temperature exposure (IBLT) and non-irrigation (NI)) and low temperatures (-2 degrees C, -4 degrees C, -6 degrees C, -8 degrees C, and -10 degrees C). The IBLT treatment effectively reduced leaf wilt, stem breakage, and spikelet desiccation. Low-temperature stress adversely impacted the yield per plant-including both original and regenerated yields-and yield components across all wheat varieties. Furthermore, a negative correlation was found between regenerated and original yields. Semi-spring varieties showed greater yield reduction than semi-winter varieties, with a more pronounced impact under NI compared to IBLT. This suggests that the compensatory regenerative yield is more significant in semi-spring varieties and under NI conditions. As low-temperature stress intensified, the primary determinant of yield loss shifted from grain number per spike (GNPS) to spike number per plant (SNPP) beyond a specific temperature threshold. Under NI, this threshold was -6 degrees C, while it was -8 degrees C under IBLT. Low-temperature stress led to variability in fruiting rate across different spike positions, with semi-spring varieties and NI conditions showing the most substantial reductions. Sensitivity to low temperatures varied across spikelet positions: Apical spikelets were the most sensitive, followed by basal, while central spikelets showed the largest reduction in grain number as stress levels increased, significantly contributing to reduced overall grain yield. Irrigation, variety, and low temperature had variable impacts on physiological indices in wheat. Structural equation modeling (SEM) analysis revealed that irrigation significantly enhanced wheat's response to cold tolerance indicators-such as superoxide dismutase (SOD), proline (Pro), and peroxidase (POD)-while reducing malondialdehyde (MDA) levels. Irrigation also improved photosynthesis (Pn), chlorophyll fluorescence (Fv/Fm), and leaf water content (LWC), thereby mitigating the adverse effects of low-temperature stress and supporting grain development in the central spike positions. In summary, IBLT effectively mitigates yield losses due to low-temperature freeze injuries, with distinct yield component contributions under varying stress conditions. Furthermore, this study clarifies the spatial distribution of grain responses across different spike positions under low temperatures, providing insights into the physiological mechanisms by which irrigation mitigates grain loss. These findings provide a theoretical and scientific basis for effective agricultural practices to counter spring freeze damage and predict wheat yield under low-temperature stress.

Background Vermicompost contains humic acids, nutrients, earthworm excretions, beneficial microbes, growth hormones, and enzymes, which help plants to tolerate a variety of abiotic stresses. Effective microorganisms (EM) include a wide range of microorganisms' e.g. photosynthetic bacteria, lactic acid bacteria, yeasts, actinomycetes, and fermenting fungi that can stimulate plant growth and improve soil fertility. To our knowledge, no study has yet investigated the possible role of vermicompost and EM dual application in enhancing plant tolerance to water scarcity. Methods Consequently, the current study investigated the effectiveness of vermicompost and EM in mitigating drought-induced changes in wheat. The experiment followed a completely randomized design with twelve treatments. The treatments included control, as well as individual and combined applications of vermicompost and EM at three different irrigation levels (100%, 70%, and 30% of field capacity). Results The findings demonstrated that the application of vermicompost and/or EM significantly improved wheat growth and productivity, as well as alleviated drought-induced oxidative damage with decreased the generation of superoxide anion radical and hydrogen peroxide. This was achieved by upregulating the activities of several antioxidant enzymes, including superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase. Vermicompost and/or EM treatments also enhanced the antioxidant defense system by increasing the content of antioxidant molecules such as ascorbate, glutathione, phenolic compounds, and flavonoids. Additionally, the overproduction of methylglyoxal in water-stressed treated plants was controlled by the enhanced activity of the glyoxalase system enzymes; glyoxalase I and glyoxalase II. The treated plants maintained higher water content related to the higher content of osmotic regulatory substances like soluble sugars, free amino acids, glycinebetaine, and proline. Conclusions Collectively, we offer the first report that identifies the underlying mechanism by which the dual application of vermicompost and EM confers drought tolerance in wheat by improving osmolyte accumulation and modulating antioxidant defense and glyoxalase systems.

Background Utilizing rice straw biochar (RSB) presents a novel approach to overcome toxicity of arsenic (As) in agricultural settings. Similarly, silicon (Si) has emerged as an effective agent for overcoming metal stress within agricultural crops. The present study investigates into the syringic application of RSB and Si in ameliorating As-induced stressed in Oryza sativa L. (rice) seedlings. Methods In the present study, we have used different levels of RSB (0, 2.5, and 5% w/w) and Si (0, 1.5, and 3 mM) to O. sativa seedlings when exposed to different levels of As stress i.e., 0, 50 and 100 mu M to examine plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators, and the response of various antioxidants (enzymatic and non-enzymatic) and their specific gene expression, proline metabolism, the AsA-GSH cycle, cellular fractionation in the plants. Results Our results showed that the increasing concentration of As in the soil significantly (P < 0.05) decreased total plant length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight by 26, 12, 18, 34, 39 and 20% respectively, compared to the plants which were grown in the 0 M of As in the soil. Additionally, As stress in the soil increased the concentration of reactive oxygen species (ROS) causes oxidative damaged to membranous bounded organelles, increases organic acids, As concentration, affects antioxidants, proline metabolism, AsA-GSH cycle and cellular fractionation. Although, Although, the application of Si and RSB showed a significant (P < 0.05) increase in plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds, and their gene expression and also decreased oxidative stress. In addition, the application of Si and RSB enhanced cellular fractionation and decreased the proline metabolism and AsA-GSH cycle in O. sativa seedlings. Conclusion These results open new insights for sustainable agriculture practices and hold immense promise in addressing the pressing challenges of heavy metal contamination in agricultural soils.

Lead (Pb) is a hazardous heavy metal that accumulates in many environments. Phytoremediation of Pb polluted soil is an environmentally friendly method, and a better understanding of mycorrhizal symbiosis under Pb stress can promote its efficiency and application. This study aims to evaluate the impact of two ectomycorrhizal fungi (Suillus grevillei and Suillus luteus) on the performance of Pinus tabulaeformis under Pb stress, and the biomineralization of metallic Pb in vitro. A pot experiment using substrate with 0 and 1,000 mg/kg Pb2+ was conducted to evaluate the growth, photosynthetic pigments, oxidative damage, and Pb accumulation of P. tabulaeformis with or without ectomycorrhizal fungi. In vitro co-cultivation of ectomycorrhizal fungi and Pb shots was used to evaluate Pb biomineralization. The results showed that colonization by the two ectomycorrhizal fungi promoted plant growth, increased the content of photosynthetic pigments, reduced oxidative damage, and caused massive accumulation of Pb in plant roots. The structural characteristics of the Pb secondary minerals formed in the presence of fungi demonstrated significant differences from the minerals formed in the control plates and these minerals were identified as pyromorphite (Pb-5(PO4)(3)Cl). Ectomycorrhizal fungi promoted the performance of P. tabulaeformis under Pb stress and suggested a potential role of mycorrhizal symbiosis in Pb phytoremediation. This observation also represents the first discovery of such Pb biomineralization induced by ectomycorrhizal fungi. Ectomycorrhizal fungi induced Pb biomineralization is also relevant to the phytostabilization and new approaches in the bioremediation of polluted environments.

Heliotropium thermophilum (Boraginaceae) plants have strong antioxidant properties. This study investigated the effectiveness of the antioxidant system in protecting the photosynthetic machinery of H. thermophilum. Plants were obtained from K & imath;z & imath;ldere geothermal area in Buharkent district, Ayd & imath;n, Turkey. Plants in the geothermal area that grew at 25-35 degrees C were regarded as the low temperature group, while those that grew at 55-65 degrees C were regarded as the high temperature group. We analysed the physiological changes of these plants at the two temperature conditions at stage pre-flowering and flowering. We meaured the effect of high soil temperature on water potential, malondialdehyde, cell membrane stability, and hydrogen peroxide analysis to determine stress levels on leaves and roots. Changes in antioxidant enzyme activities, ascorbate and chlorophyll content, chlorophyll fluorescence, photosynthetic gas exchange parameters, and photosynthetic enzymes (Rubisco and invertase) activities were also determined. Our results showed minimal changes to stress levels, indicating that plants were tolerant to high soil temperatures. In general, an increase in antioxidant enzyme activities, ascorbat levels, and all chlorophyll fluorescence parameters except for non-photochemical quenching (NPQ) and F-v/F-m were observed. The pre-flowering and flowering stages were both characterised by decreased NPQ, despite F-v/F-m not changing. Additionally, there was a rise in the levels of photosynthetic gas exchange parameters, Rubisco, and invertase activities. High temperature did not affect photosynthetic yield because H. thermophilum was found to stimulate antioxidant capacity, which reduces oxidative damage and maintains its photosynthetic machinery in high temperature conditions and therefore, it is tolerant to high soil temperature.