Combined application of arbuscular mycorrhizal fungi and selenium fertilizer increased wheat biomass under cadmium stress and shapes rhizosphere soil microbial communities.

BACKGROUND: Selenium (Se) fertilizer and arbuscular mycorrhizal fungi (AMF) are known to modulate cadmium (Cd) toxicity in plants. However, the effects of their co-application on wheat growth and soil microbial communities in Cd-contaminated soil are unclear. RESULTS: A pot experiment inoculation with two types of AMF and the application of Se fertilizer under Cd stress in wheat showed that inoculation AMF alone or combined with Se fertilizer significantly increased wheat biomass. Se and AMF alone or in combination significantly reduced available Cd concentration in wheat and soil, especially in the Se combined with Ri treatment. High throughput sequencing of soil samples indicated that Se and AMF application had stronger influence on bacterial community compared to fungal community and the bacterial network seemed to have more complex interconnections than the fungal network, and finally shaped the formation of specific microflora to affect Cd availability. CONCLUSION: These results indicate that the application of Se and AMF, particularly in combination, could successfully decrease soil Cd availability and relieve the harm of Cd in wheat by modifying rhizosphere soil microbial communities.

Seeds Priming with Melatonin Improves Root Hydraulic Conductivity of Wheat Varieties under Drought, Salinity, and Combined Stress.

Drought and salinity stress reduce root hydraulic conductivity of plant seedlings, and melatonin application positively mitigates stress-induced damage. However, the underlying effect of melatonin priming on root hydraulic conductivity of seedlings under drought-salinity combined remains greatly unclear. In the current report, we investigated the influence of seeds of three wheat lines' 12 h priming with 100 µM of melatonin on root hydraulic conductivity (Lpr) and relevant physiological indicators of seedlings under PEG, NaCl, and PEG + NaCl combined stress. A previous study found that the combined PEG and NaCl stress remarkably reduced the Lpr of three wheat varieties, and its value could not be detected. Melatonin priming mitigated the adverse effects of combined PEG + NaCl stress on Lpr of H4399, Y1212, and X19 to 0.0071 mL·h-1·MPa-1, 0.2477 mL·h-1·MPa-1, and 0.4444 mL·h-1·MPa-1, respectively, by modulating translation levels of aquaporin genes and contributed root elongation and seedlings growth. The root length of H4399, Y1212, and X19 was increased by 129.07%, 141.64%, and 497.58%, respectively, after seeds pre-treatment with melatonin under PEG + NaCl combined stress. Melatonin -priming appreciably regulated antioxidant enzyme activities, reduced accumulation of osmotic regulators, decreased levels of malondialdehyde (MDA), and increased K+ content in stems and root of H4399, Y1212, and X19 under PEG + NaCl stress. The path investigation displayed that seeds primed with melatonin altered the modification of the path relationship between Lpr and leaf area under stress. The present study suggested that melatonin priming was a strategy as regards the enhancement of root hydraulic conductivity under PEG, NaCl, and PEG + NaCl stress, which efficiently enhanced wheat resistant to drought-salinity stress.

Impact of Fe3O4-porphyrin hybrid nanoparticles on wheat: Physiological and metabolic advance.

Iron-magnetic nanoparticles (Fe-NMPs) are widely used in environmental remediation, while porphyrin-based hybrid materials anchored to silica-coated Fe3O4-nanoparticles (Fe3O4-NPs) have been used for water disinfection purposes. To assess their safety on plants, especially concerning potential environmental release, it was investigated for the first time, the impact on plants of a silica-coated Fe3O4-NPs bearing a porphyrinic formulation (FORM) - FORM@NMP. Additionally, FORM alone and the magnetic nanoparticles without FORM anchored (NH2@NMP) were used for comparison. Wheat (Triticum aestivum L.) was chosen as a model species and was subjected to three environmentally relevant doses during germination and tiller development through root application. Morphological, physiological, and metabolic parameters were assessed. Despite a modest biomass decrease and alterations in membrane properties, no major impairments in germination or seedling development were observed. During tiller phase, both Fe3O4-NPs increased leaf length, and photosynthesis exhibited varied impacts: both Fe3O4-NPs and FORM alone increased pigments; only Fe3O4-NPs promoted gas exchange; all treatments improved the photochemical phase. Regarding oxidative stress, lipid peroxidation decreased in FORM and FORM@NMP, yet with increased O2-• in FORM@NMP; total flavonoids decreased in NH2@NMP and antioxidant enzymes declined across all materials. Phenolic profiling revealed a generalized trend towards a decrease in flavones. In conclusion, these nanoparticles can modulate wheat physiology/metabolism without apparently inducing phytotoxicity at low doses and during short-time exposure. ENVIRONMENTAL IMPLICATION: Iron-magnetic nanoparticles are widely used in environmental remediation and fertilization, besides of new applications continuously being developed, making them emerging contaminants. Soil is a major sink for these nanoparticles and their fate and potential environmental risks in ecosystems must be addressed to achieve more sustainable environmental applications. Furthermore, as the reuse of treated wastewater for agricultural irrigation is being claimed, it is of major importance to disclose the impact on crops of the nanoparticles used for wastewater decontamination, such as those proposed in this work.

Peroxidase like Zn doped Prussian blue facilitates salinity tolerance in winter wheat through seed dressing.

Salt stress severely limits the growth and yield of wheat in saline-alkali soil. While nanozymes have shown promise in mitigating abiotic stress by scavenging reactive oxygen species (ROS) in plants, their application in alleviating salt stress for wheat is still limited. This study synthesized a highly active nanozyme catalyst known as ZnPB (Zn-modified Prussian blue) to improve the yield and quality of wheat in saline soil. According to the Michaelis-Menten equation, ZnPB demonstrates exceptional peroxidase-like enzymatic activity, thereby mitigating oxidative damage caused by salt stress. Additionally, studies have shown that the ZnPB nanozyme is capable of regulating intracellular Na+ efflux and K+ retention in wheat, resulting in a decrease in proline and soluble protein levels while maintaining the integrity of macromolecules within the cell. Consequently, field experiments demonstrated that the ZnPB nanozyme increased winter wheat yield by 12.15 %, while also significantly enhancing its nutritional quality. This research offers a promising approach to improving the salinity tolerance of wheat, while also providing insights into its practical application.

Features of the Effect of Quercetin on Different Genotypes of Wheat under Hypoxia.

Hypoxia is one of the common abiotic stresses that negatively affects the development and productivity of agricultural crops. Quercetin is used to protect plants from oxidative stress when exposed to environmental stressors. O2 deficiency leads to impaired development and morphometric parameters in wheat varieties Orenburgskaya 22 (Triticum aestivum L.) and varieties Zolotaya (Triticum durum Desf.). Cytological analysis revealed various types of changes in the cytoplasm under conditions of hypoxia and treatment with quercetin. The most critical changes in the cytoplasm occur in the Zolotaya variety during pretreatment with quercetin followed by hypoxia, and in the Orenburgskaya 22 variety during hypoxia. Quercetin has a protective effect only on the Orenburgskaya 22 variety, and also promotes a more effective recovery after exposure to low O2 content. Hypoxia causes an increase in reactive oxygen species and activates the antioxidant system. It has been shown that the most active components of the antioxidant system in the Orenburgskaya 22 variety are MnSOD and Cu/ZnSOD, and in the Zolotaya variety GSH. We have shown that quercetin provides resistance only to the wheat genotype Orenburgskaya 22, as a protective agent against abiotic stress, which indicates the need for a comprehensive study of the effects of exogenous protectors before use in agriculture.

Temperature fluctuation in soil alters the nanoplastic sensitivity in wheat.

Despite the wide acknowledgment that plastic pollution and global warming have become serious agricultural concerns, their combined impact on crop growth remains poorly understood. Given the unabated megatrend, a simulated soil warming (SWT, +4 °C) microcosm experiment was carried out to provide a better understanding of the effects of temperature fluctuations on wheat seedlings exposed to nanoplastics (NPs, 1 g L-1 61.71 ± 0.31 nm polystyrene). It was documented that SWT induced oxidative stress in wheat seedlings grown in NPs-contaminated soil, with an 85.56 % increase in root activity, while decreasing plant height, fresh weight, and leaf area by 8.72 %, 47.68 %, and 15.04 % respectively. The SWT also resulted in reduced photosynthetic electron-transfer reaction and Calvin-Benson cycle in NPs-treated plants. Under NPs, SWT stimulated the tricarboxylic acid (TCA) metabolism and bio-oxidation process. The decrease in photosynthesis and the increase in respiration resulted in an 11.94 % decrease in net photosynthetic rate (Pn). These results indicated the complicated interplay between climate change and nanoplastic pollution in crop growth and underscored the potential risk of nanoplastic pollution on crop production in the future climate.

Perfluorobutanoic acid triggers metabolic and transcriptional reprogramming in wheat seedlings.

The environmental risks of fluorinated alternatives are of great concern with the phasing out of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate. Here, multi-omics (i.e., metabolomics and transcriptomics) coupled with physiological and biochemical analyses were employed to investigate the stress responses of wheat seedings (Triticum aestivum L.) to perfluorobutanoic acid (PFBA), one of the short-chain per- and polyfluoroalkyl substances (PFAS) and PFOA alternatives, at environmentally relevant concentrations (0.1-100 ng/g). After 28 days of soil exposure, PFBA boosted the generation of OH and O2- in wheat seedlings, resulting in lipid peroxidation, protein perturbation and impaired photosynthesis. Non-enzymatic antioxidant defense systems (e.g., glutathione, phenolics, and vitamin C) and enzymatic antioxidant copper/zinc superoxide dismutase were strikingly activated (p < 0.05). PFBA-triggered oxidative stress induced metabolic and transcriptional reprogramming, including carbon and nitrogen metabolisms, lipid metabolisms, immune responses, signal transduction processes, and antioxidant defense-related pathways. Down-regulation of genes related to plant-pathogen interaction suggested suppression of the immune-response, offering a novel understanding on the production of reactive oxygen species in plants under the exposure to PFAS. The identified MAPK signaling pathway illuminated a novel signal transduction mechanism in plant cells in response to PFAS. These findings provide comprehensive understandings on the phytotoxicity of PFBA to wheat seedlings and new insights into the impacts of PFAS on plants.

Effects of Streptomyces sp. HU2014 inoculation on wheat growth and rhizosphere microbial diversity under hexavalent chromium stress.

Wheat (Triticum aestivum L.) is a major foodstuff for over 40% of the world's population. However, hexavalent chromium [Cr(VI)] in contaminated soil significantly affects wheat production and its ecological environment. Streptomyces sp. HU2014 was first used to investigate the effects of Cr (VI) stress on wheat growth. We analyzed the Cr(VI) concentration, physicochemical properties of wheat and soil, total Cr content, and microbial community structures during their interactions. HU2014 reduced the toxicity of Cr(VI) and promoted wheat growth by increasing total nitrogen, nitrate nitrogen, total phosphorus, and Olsen-phosphorus in Cr(VI)-contaminated soil. These four soil variables had strong positive effects on two bacterial taxa, Proteobacteria and Bacteroidota, in the HU2014 treatments. In addition, the level of the dominant Proteobacteria positively correlated with the total Cr content in the soil. Among the fungal communities, which had weaker correlations with soil variables compared with bacterial communities, Ascomycota was the most abundant. Our findings suggest that HU2014 can promote the phytoremediation of Cr(VI)-contaminated soil.

Polystyrene nanoplastics in soil impair drought priming-induced low temperature tolerance in wheat.

Drought priming is known to enhance plant low temperature tolerance, whereas polystyrene nanoplastic contamination exerts detrimental effects on plant growth. This study investigates the less-explored influence of nanoplastic contamination on cold stress tolerance in drought-primed plants. We compared the photosynthetic carbon assimilation, carbohydrate metabolism, reactive oxygen species metabolism, and grain yield between the non-primed and drought-primed wheat grown in both nanoplastic-contaminated and healthy soils. Our results reveal that the beneficial effects of drought priming on photosynthetic carbon assimilation and the efficiency of the "water-water" cycle were compromised in the presence of nanoplastics (nPS). Additionally, nPS exposure disturbed carbohydrate metabolism, which impeded source-to-sink transport of sugar and resulted in reduced grain yield in drought-primed plants under low temperature conditions. These findings unveil the suppression of nPS on drought-primed low-temperature tolerance (DPLT) in wheat plants, suggesting an intricate interplay between the induction of stress tolerance and responses to nPS contamination. The study raises awareness about a potential challenge for future crop production.

Astaxanthin induces plant tolerance against cadmium by reducing cadmium uptake and enhancing carotenoid metabolism for antioxidant defense in wheat (Triticum aestivum L.).

Soil cadmium (Cd) contamination poses a significant threat to global food security and the environment. Astaxanthin (AX), a potent biological antioxidant belonging to the carotenoid group, has been demonstrated to confer tolerance against diverse abiotic stresses in plants. This study investigated the potential of AX in mitigating Cd-induced damage in wheat seedlings. Morpho-physiological, ultrastructural, and biochemical analyses were conducted to evaluate the impact of AX on Cd-exposed wheat seedlings. Illumina-based gene expression profiling was employed to uncover the molecular mechanisms underlying the protective effects of AX. The addition of 100 µM AX alleviated Cd toxicity by enhancing various parameters: growth, photosynthesis, carotenoid content, and total antioxidant capacity (T-AOC), while reducing Cd accumulation, malondialdehyde (MDA), and hydrogen peroxide (H2O2) levels. RNA sequencing analysis revealed differentially expressed genes associated with Cd uptake and carotenoid metabolism, such as zinc/iron permease (ZIP), heavy metal-associated protein (HMA), 3-beta hydroxysteroid dehydrogenase/isomerase (3-beta-HSD), and thiolase. These findings suggest that AX enhances Cd tolerance in wheat seedlings by promoting the expression of detoxification and photosynthesis-related genes. This research offers valuable insights into the potential use of AX to address Cd contamination in agricultural systems, highlighting the significance of antioxidant supplementation in plant stress management.

Field application of Ca-doped ZnO nanoparticles to maize and wheat plants.

Nanoparticles play a vital role in modern agriculture to provide the nutrients required by plants. Herein, we report the preparation of calcium-doped zinc oxide nanoparticles (CZO NPs) via a simple and cost-effective co-precipitation method, with the aim of realizing increased fertilizer response. The synthesized nanoparticles were analyzed to study their physicochemical properties using various characterization techniques. The X-ray diffraction pattern showed a small shift in peak position towards higher values of 2θ and reduced crystal size after the zinc oxide (ZnO) matrix had been doped with Ca. Field-emission scanning electron microscopy images clearly revealed a grain-like surface morphology. The X-ray photoelectron spectroscopy study produced evidence of Zn2+ substitution by Ca2+ and enhanced Zn-O bond strengths in the CZO samples. Two major crops, maize (Zea mays L.) and wheat (Triticum aestivum L.) were selected to study the impact of the CZO NP-based nanofertilizer on plant growth. During the study, the effect of the CZO-based fertilizer on growth parameters such as seed germination, root and shoot length, plant height, root and stem width, number of leaves, and leaf size was studied based on comparisons with control plants. We observed significantly increased plant growth parameters after the application of the CZO NP-based fertilizers.

Assessment of Biological Activities and Genomic Changes on Microorganisms, Wheat, and Wilding Arise from Poly(pyrazole).

The rapidly growing human population has led to duplicate food production and also reduced product loss. Although the negative effects of synthetic chemicals were recorded, they are still used as agrochemical. The production of non-toxic synthetics makes their use particularly safe. The goal of our research is to evaluate antimicrobial activity of previously synthesized Poly(p-phenylene-1-(2,5-dimethylphenyl)-5-phenyl-1H-pyrazole-3,4-dicarboxy amide) (poly(PDPPD)) against selected Gram-negative, Gram-positive bacteria, and fungus. In addition, the possible genotoxic effects of the poly(PDPPD) were searched on Triticum vulgare and Amaranthus retroflexus seedlings using Random Amplified Polymorphic DNA (RAPD) marker. The binding affinity and binding energies of the synthesized chemical to B-DNA were simulated with AutoDock Vina. It was observed that the poly(PDPPD) affected most of the organisms in a dose-dependent manner. Pseudomonas aeruginosa was the most affected species in tested bacteria at 500 ppm with 21.5 mm diameters. Similarly, a prominent activity was observed for tested fungi. The poly(PDPPD) decreased root and stem length of the Triticum vulgare and Amaranthus retroflexus seedlings and also reduced the genomic template stability (GTS) value of Triticum vulgare more than Amaranthus retroflexus. The binding energy of poly(PDPPD) was found in range of -9.1 and -8.3 kcal/mol for nine residues of B-DNA.

Metallic nanoparticles photodegraded antibiotics and co-application improved wheat growth and nutritional quality through stress alleviation.

Antibiotics are now considered as emerging environmental pollutants due to their persistent nature and continuous exposure through irrigation with wastewater contaminated with antibiotics. The aim of present study was to assess the potential of nanoparticles for the photodegradation of antibiotics and subsequent stress alleviation via Titania oxide (TiO2) application for improvement in crop productivity and quality in terms of the nutritional composition. In the first phase, different nanoparticles, TiO2, Zinc oxide (ZnO), and Iron oxide (Fe2O3) with varying concentrations (40-60 mg L-1) and time-periods (1-9 days) were tested to degrade amoxicillin (Amx) and levofloxacin (Lev) @ 5 mg L-1 under the visible light. Results indicated that TiO2 nanoparticles (50 mg L-1) were the most effective nanoparticles for the removal of both antibiotics with maximum degradation of 65% and 56% for Amx and Lev, respectively, on the 7th day. In the second phase, a pot experiment was conducted in which TiO2 (50 mg L-1) was applied individually and along with antibiotics (5 mg L-1) in order to evaluate the effect of nanoparticles on stress alleviation for growth promotion of wheat exposed to antibiotics. Plant biomass was reduced by Amx (58.7%) and Lev (68.4%) significantly (p < 0.05) when compared to the control. However, co-application of TiO2 and antibiotics improved the total iron (34.9% and 42%), carbohydrate (33% and 31%), and protein content (36% and 33%) in grains under Amx and Lev stress, respectively. The highest plant length, grain weight, and nutrient uptake were observed upon application of TiO2 nanoparticles alone. Total iron, carbohydrates, and proteins in grains were significantly increased by 52%, 38.5%, and 40%, respectively compared to the control (with antibiotics). The findings highlight the potential of TiO2 nanoparticles for stress alleviation, growth, and nutritional improvement under antibiotic stress upon irrigation with contaminated wastewater.

Photosystems and antioxidative system of rye, wheat and triticale under Pb stress.

Lead (Pb2+) pollution in the soil sub-ecosystem has been a continuously growing problem due to economic development and ever-increasing anthropogenic activities across the world. In this study, the photosynthetic performance and antioxidant capacity of Triticeae cereals (rye, wheat and triticale) were compared to assess the activities of antioxidants, the degree of oxidative damage, photochemical efficiency and the levels of photosynthetic proteins under Pb stress (0.5 mM, 1 mM and 2 mM Pb (NO3)2). Compared with triticale, Pb treatments imposed severe oxidative damage in rye and wheat. In addition, the highest activity of major antioxidant enzymes (SOD, POD, CAT, and GPX) was also found to be elevated. Triticale accumulated the highest Pb contents in roots. The concentration of mineral ions (Mg, Ca, and K) was also high in its leaves, compared with rye and wheat. Consistently, triticale showed higher photosynthetic activity under Pb stress. Immunoblotting of proteins revealed that rye and wheat have significantly lower levels of D1 (photosystem II subunit A, PsbA) and D2 (photosystem II subunit D, PsbD) proteins, while no obvious decrease was noticed in triticale. The amount of light-harvesting complex II b6 (Lhcb6; CP24) and light-harvesting complex II b5 (Lhcb5; CP26) was significantly increased in rye and wheat. However, the increase in PsbS (photosystem II subunit S) protein only occurred in wheat and triticale exposed to Pb treatment. Taken together, these findings demonstrate that triticale shows higher antioxidant capacity and photosynthetic efficiency than wheat and rye under Pb stress, suggesting that triticale has high tolerance to Pb and could be used as a heavy metal-tolerant plant.

The impact of chitosan on the early metabolomic response of wheat to infection by Fusarium graminearum.

BACKGROUND: Chitosan has shown potential for the control of Fusarium head blight (FHB) disease caused by Fusarium graminearum. The objective of this study was to compare the effect of chitosan hydrochloride applied pre- or post-fungal inoculation on FHB and to better understand its' mode of action via an untargeted metabolomics study. RESULTS: Chitosan inhibited fungal growth in vitro and, when sprayed on the susceptible wheat cultivar Remus 24 hours pre-inoculation with F. graminearum, it significantly reduced the number of infected spikelets at 7, 14 and 21 days post-inoculation. Chitosan pre-treatment also increased the average grain weight per head, the number of grains per head and the 1000-grain weight compared to the controls sprayed with water. No significant impact of chitosan on grain yield was observed when the plants were sprayed 24 hours post-inoculation with F. graminearum, even if it did result in a reduced number of infected spikelets at every time point. An untargeted metabolomic study using UHPLC-QTOF-MS on wheat spikes revealed that spraying the spikes with both chitosan and F. graminearum activated known FHB resistance pathways (e.g. jasmonic acid). Additionally, more metabolites were up- or down-regulated when both chitosan and F. graminearum spores were sprayed on the spikes (117), as compared with chitosan (51) or F. graminearum on their own (32). This included a terpene, a terpenoid and a liminoid previously associated with FHB resistance. CONCLUSIONS: In this study we showed that chitosan hydrochloride inhibited the spore germination and hyphal development of F. graminearum in vitro, triggered wheat resistance against infection by F. graminearum when used as a pre-inoculant, and highlighted metabolites and pathways commonly and differentially affected by chitosan, the pathogen and both agents. This study provides insights into how chitosan might provide protection or stimulate wheat resistance to infection by F. graminearum. It also unveiled new putatively identified metabolites that had not been listed in previous FHB or chitosan-related metabolomic studies.

Salicylic Acid Enhances Adventitious Root and Aerenchyma Formation in Wheat under Waterlogged Conditions.

The present study investigated the role of salicylic acid (SA) in regulating morpho-anatomical adaptive responses of a wheat plant to waterlogging. Our pharmacological study showed that treatment of waterlogged wheat plants with exogenous SA promotes the formation axile roots and surface adventitious roots that originate from basal stem nodes, but inhibits their elongation, leading to the formation of a shallow root system. The treatment also enhanced axile root formation in non-waterlogged plants but with only slight reductions in their length and branch root formation. Exogenous SA enhanced the formation of root aerenchyma, a key anatomical adaptive response of plants to waterlogging. Consistent with these results, waterlogging enhanced SA content in the root via expression of specific isochorismate synthase (ICS; ICS1 and ICS2) and phenylalanine ammonia lyase (PAL; PAL4, PAL5 and PAL6) genes and in the stem nodes via expression of specific PAL (PAL5 and PAL6) genes. Although not to the same level observed in waterlogged plants, exogenous SA also induced aerenchyma formation in non-waterlogged plants. The findings of this study furthermore indicated that inhibition of ethylene synthesis in SA treated non-waterlogged and waterlogged plants does not have any effect on SA-induced emergence of axile and/or surface adventitious roots but represses SA-mediated induction of aerenchyma formation. These results highlight that the role of SA in promoting the development of axile and surface adventitious roots in waterlogged wheat plants is ethylene independent while the induction of aerenchyma formation by SA requires the presence of ethylene.

Biochemical and structural characterization of quizalofop-resistant wheat acetyl-CoA carboxylase.

A novel nucleotide mutation in ACC1 resulting in an alanine to valine amino acid substitution in acetyl-CoA carboxylase (ACCase) at position 2004 of the Alopecurus myosuroides reference sequence (A2004V) imparts quizalofop resistance in wheat. Genotypes endowed with the homozygous mutation in one or two ACC1 homoeologs are seven- and 68-fold more resistant to quizalofop than a wildtype winter wheat in greenhouse experiments, respectively. In vitro ACCase activities in soluble protein extracts from these varieties are 3.8- and 39.4-fold more resistant to quizalofop with the homozygous mutation in either one or two genomes, relative to the wildtype. The A2004V mutation does not alter the specific activity of wheat ACCase, suggesting that this resistance trait does not affect the catalytic functions of ACCase. Modeling of wildtype and quizalofop-resistant wheat ACCase demonstrates that the A2004V amino acid substitution causes a reduction in the volume of the binding pocket that hinders quizalofop's interaction with ACCase. Docking studies confirm that the mutation reduces the binding affinity of quizalofop. Interestingly, the models suggest that the A2004V mutation does not affect haloxyfop binding. Follow up in vivo and in vitro experiments reveal that the mutation, in fact, imparts negative cross-resistance to haloxyfop, with quizalofop-resistant varieties exhibiting higher sensitivity to haloxyfop than the wildtype winter wheat line.

Nutrient use efficiency (NUE) of wheat (Triticum aestivum L.) as affected by NPK fertilization.

Nutrient use efficiency is crucial for increasing crop yield and quality while reducing fertilizer inputs and minimizing environmental damage. The experiments were carried out in silty clay loam soil of Lalitpur, Nepal, to examine how different amounts of nitrogen (N), phosphorus (P), and potassium (K) influenced crop performance and nutrient efficiency indices in wheat during 2019/20 and 2020/21. The field experiment comprised three factorial randomized complete block designs that were replicated three times. N levels (100, 125, 150 N kg ha-1), P levels (25, 50, 75 P2O5 kg ha-1), and K levels (25, 50, 75 K2O kg ha-1) were three factors evaluated, with a total of 27 treatment combinations. Grain yields were significantly increased by N and K levels and were optimum @ 125 kg N ha-1 and @ 50 kg K2O ha-1 with grain yields of 6.33 t ha-1 and 6.30 t ha-1, respectively. Nutrient levels influenced statistically partial factor productivity, internal efficiency, partial nutrient budget, recovery efficiency, agronomic efficiency, and physiological efficiency of NPK for wheat. Nutrient efficiency was found to be higher at lower doses of their respective nutrients. Higher P and K fertilizer rates enhanced wheat N efficiencies, and the case was relevant for P and K efficiencies as well. Wheat was more responsive to N and K fertilizer, and a lower rate of P application reduced N and K fertilizer efficiency. This study recommends to use N @ 125 kg ha-1, P2O5 @ 25 kg ha-1 and K2O @ 50 kg ha-1 as an optimum rate for efficient nutrient management in wheat in mid-hills of Nepal.

Potential of Trichoderma harzianum and Its Metabolites to Protect Wheat Seedlings against Fusarium culmorum and 2,4-D.

Wheat is a critically important crop. The application of fungi, such as Trichoderma harzianum, to protect and improve crop yields could become an alternative solution to synthetic chemicals. However, the interaction between the fungus and wheat in the presence of stress factors at the molecular level has not been fully elucidated. In the present work, we exposed germinating seeds of wheat (Triticum aestivum) to the plant pathogen Fusarium culmorum and the popular herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence of T. harzianum or its extracellular metabolites. Then, the harvested roots and shoots were analyzed using spectrometry, 2D-PAGE, and MALDI-TOF/MS techniques. Although F. culmorum and 2,4-D were found to disturb seed germination and the chlorophyll content, T. harzianum partly alleviated these negative effects and reduced the synthesis of zearalenone by F. culmorum. Moreover, T. harzianum decreased the activity of oxidoreduction enzymes (CAT and SOD) and the contents of the oxylipins 9-Hode, 13-Hode, and 13-Hotre induced by stress factors. Under the influence of various growth conditions, changes were observed in over 40 proteins from the wheat roots. Higher volumes of proteins and enzymes performing oxidoreductive functions, such as catalase, ascorbate peroxidase, cytochrome C peroxidase, and Cu/Zn superoxide dismutase, were found in the Fusarium-inoculated and 2,4-D-treated wheat roots. Additionally, observation of the level of 12-oxo-phytodienoic acid reductase involved in the oxylipin signaling pathway in wheat showed an increase. Trichoderma and its metabolites present in the system leveled out the mentioned proteins to the control volumes. Among the 30 proteins examined in the shoots, the expression of the proteins involved in photosynthesis and oxidative stress response was found to be induced in the presence of the herbicide and the pathogen. In summary, these proteomic and metabolomic studies confirmed that the presence of T. harzianum results in the alleviation of oxidative stress in wheat induced by 2,4-D or F. culmorum.

Microtubule organization changes severely after mannitol and n-butanol treatments inducing microspore embryogenesis in bread wheat.

BACKGROUND: A mannitol stress treatment and a subsequent application of n-butanol, known as a microtubule-disrupting agent, enhance microspore embryogenesis (ME) induction and plant regeneration in bread wheat. To characterize changes in cortical (CMT) and endoplasmic (EMT) microtubules organization and dynamics, associated with ME induction treatments, immunocytochemistry studies complemented by confocal laser scanning microscopy (CLSM) were accomplished. This technique has allowed us to perform advanced 3- and 4D studies of MT architecture. The degree of MT fragmentation was examined by the relative fluorescence intensity quantification. RESULTS: In uni-nucleated mannitol-treated microspores, severe CMT and EMT fragmentation occurs, although a complex network of short EMT bundles protected the nucleus. Additional treatment with n-butanol resulted in further depolymerization of both CMT and EMT, simultaneously with the formation of MT aggregates in the perinuclear region. Some aggregates resembled a preprophase band. In addition, a portion of the microspores progressed to the first mitotic division during the treatments. Bi-nucleate pollen-like structures showed a high MT depolymerization after mannitol treatment and numerous EMT bundles around the vegetative and generative nuclei after n-butanol. Interestingly, bi-nucleate symmetric structures showed prominent stabilization of EMT. CONCLUSIONS: Fragmentation and stabilization of microtubules induced by mannitol- and n-butanol lead to new configurations essential for the induction of microspore embryogenesis in bread wheat. These results provide robust insight into MT dynamics during EM induction and open avenues to address newly targeted treatments to induce ME in recalcitrant species.