Stress Conditions Research Articles

Rhizobacteria Enterobacter sp. LHB11 and Bacillus sp. PIXIE Induced Systemic Tolerance Against Drought Stress in Tomato (Solanum lycopersicum)

Plant growth-promoting rhizobacteria (PGPR) induce changes in the plant metabolism, improving plant growth under drought stress conditions by employing different mechanisms of interaction. In this study, two bacterial strains (Enterobacter sp. LHB11 and Bacillus sp. PIXIE) were evaluated in vitro regarding their PGPR traits, including the ACC-Deaminase enzyme activity. Both PGPR strains produced indole acetic acid (40.65–75.81 µg−1mL−1), exopolysaccharides (39.23–40.20 µg eq CR mL−1), proline (61.5–106.1 mM), and volatile organic compounds. Furthermore, both solubilized phosphate (1.15–1.53 ratio, halo/colony) and fixed the atmospheric nitrogen. Only LHB11 showed ACC-Deaminase activity. Furthermore, both strains tolerated osmotic stress induced in liquid media with up to 20% of Polyethylene glycol-6000. In a drought stress pot experiment, both strains were applied to tomato roots, exposed to normal irrigation (100%) and drought stress (decreasing irrigation by 50%). The inoculation of both strains improved the plant growth parameters under stress conditions significantly, e.g., the root dry weight (+41.0–43.4%), while the proline content decreased to a level similar to the unstressed control. In addition, strain inoculation increased the total phenolic content and the antioxidant capacity measured as the inhibitions of the ABTS radical and as the reduction in ferric ions and increased the catalase and ascorbate peroxidase enzyme activity. The bacterial contribution to the changes in biochemical parameters is higher than in morphological parameters. At the same time, the strains modulate specific parameters depending on the stress condition, e.g., ABTS, catalase activity, and proline content. In conclusion, both strains Induced Systemic Tolerance (IST), regardless of their capacity to use the ACC-Deaminase mechanism, by modulating several mechanisms of plant response to drought stress. Our results showcase the relevance of considering the orchestration of several plant response mechanisms in order to fully assess the potential and efficiency of the plant–PGPR interaction under drought stress.

Knockdown of OsPHP1 Leads to Improved Yield Under Salinity and Drought in Rice via Regulating the Complex Set of TCS Members and Cytokinin Signalling.

Plant two-component system (TCS) is crucial for phytohormone signalling, stress response, and circadian rhythms, yet the precise role of most of the family members in rice remain poorly understood. In this study, we investigated the function of OsPHP1, a pseudo-histidine phosphotransfer protein in rice, using a functional genomics approach. OsPHP1 is localised in the nucleus and cytosol, and it exhibits strong interactions with all sensory histidine kinase proteins (OsHK1-6) and cytokinin catabolism genes. Our results demonstrate that OsPHP1 functions as a negative regulator of cytokinin signalling. Knockdown of OsPHP1 enhanced the expression of positive cytokinin signalling regulators, such as OsHKs and OsAHPs (authentic phosphotransfer proteins), while downregulating negative regulators, such as type-A response regulators (OsRRs) and cytokinin catabolism genes (CKXs). Furthermore, OsPHP1 negatively influences abiotic stress tolerance, as evidenced by the increased sensitivity of OsPHP1-OE (overexpression) lines to salinity and drought. In contrast, OsPHP1-KD (knockdown) lines showed enhanced stress resilience, with better photosynthesis, increased tiller and panicle production, higher spikelet fertility, and grain filling. The study demonstrates that OsPHP1 suppresses antioxidant and stress-responsive genes, exacerbating ion toxicity and reducing osmolyte accumulation, thereby impairing plant growth and yield under stress conditions. These findings highlight OsPHP1 as a critical modulator of plant responses to abiotic stress and suggest potential genetic targets for enhancing crop stress tolerance.

Changes in the Content of microRNA775a and its Role in Post-Transcriptional Regulation of Targeted Genes in Corn Leaves under Hypoxia

Under the influence of hypoxia in the plant organism, the transcription of genes responsible for adaptation to stress caused by low oxygen levels changes. Changes in metabolic pathways under stress conditions may be regulated by microRNAs. It was found that the content of microRNA775A increases in corn leaves under the influence of hypoxia. The use of the fluorescent probe miR775A-ROX made it possible to establish an increase in the number of RNA-inducing silencing complexes (RISC), formed on the basis of microRNA775A, in maize leaves during the development of hypoxic stress. The results obtained indicate that microRNA775A is involved in the processes of adaptation of the body to hypoxic conditions by regulating the expression of target genes at the post-transcriptional level using the RNA interference mechanism.

Synergistic Effect of Iron and Zinc Nanoparticles with Recommended Nitrogen Dose on Production and Grain Quality of Maize (Zea mays L.) Cultivars Under Drought Stress

Abiotic factors, such as drought, can significantly impact the vegetative growth and productivity of maize. To investigate the effects of the combined foliar application of zinc (Zn) and iron (Fe) nanoparticles with the recommended nitrogen dose (RND) on maize production and grain chemical composition under different water regimes, two field experiments were conducted in El-Ayyat city, Giza, Egypt, during the summer seasons of 2022 and 2023. This study utilized a split-split-plot experimental design with three replications. The main plots were designated to different water regimes (100, 80, 60, and 40% of estimated evapotranspiration), while the sub-plots were randomly distributed with Zn and Fe nanoparticle concentrations (0, 100, and 200 mg/L). The sub-sub-plots were randomly allocated to three maize cultivars (SC-P3062, SC-32D99, and SC-P3433). The results revealed that exposure to drought conditions resulted in a significant decline in the yield and yield-related attributes across all maize cultivars examined. Grain yield decreased by 10–50% under drought conditions. However, the foliar application of Zn and Fe nanoparticles was found to significantly improve grain yield, protein content, oil content, starch content, crude fiber, ash, and macro- and micronutrient concentrations in the maize cultivars under control and drought stress conditions. The foliar application of Zn and Fe nanoparticles at a concentration of 200 mg/L to the SC-P3433 maize cultivar led to the greatest grain yield per hectare, reaching 11,749 and 11,657 kg under the irrigation regimes with 100 and 80% total evapotranspiration, respectively. According to the assessment using the relative drought index, the SC-P3062 maize cultivar demonstrated tolerance (T) to water stress conditions. In conclusion, the foliar application of Zn and Fe nanoparticles (100–200 mg/L) effectively mitigated the negative effects of drought stress on maize plants. This approach can be recommended for farmers in arid and semi-arid regions to maintain and improve maize yield and grain quality under water-deficit conditions.

Molecular evolution and interaction of ROS with ion transport for plant abiotic stresses

AbstractReactive oxygen species (ROS) serve as crucial signaling molecules in plants, enabling rapid responses to environmental stresses such as abiotic factors. ROS production primarily stems from the activation of enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and peroxidases, as well as disruptions in the respiratory and photosynthetic electron transport chains. This oxidative stress triggers signaling pathways that involve in calcium ion (Ca2+) influx across cell membranes, altering ionic conductance. ROS encompass hydroxyl radicals (OH•) and hydrogen peroxide (H2O2), which activate hyperpolarization‐activated Ca2+ channels and influence ion transport dynamics. Our review focuses on the mechanisms driving ROS generation and ion transport during plant responses to abiotic stress. We explore the regulation, characteristics, and potential structures of ROS‐activated ion channels in plants. Specifically, we examine the molecular responses and evolutionary adaptations of Shaker‐type K+ channels (AKT/KAT/GORK/SKOR) under stress conditions. Comparative genetic analyses highlight the conservation of these channels and other ROS‐regulated proteins (e.g., MDHAR, POX, and RBOH), suggesting their essential roles in plant to adapt to diverse stresses. This study underscores the significance of ROS‐regulated proteins in plant stress responses, advocating for further research to elucidate their fundamental roles.

Promising strains of phosphate-mobilizing rhizobacteria resistant to glyphosate and nickel

A search was carried out for phosphate-soluble rhizobacteria capable of growing in the presence of different concentrations of the herbicide glyphosate and nickel heavy metal ions (Ni2+). Using the Muromtsev medium, the phosphate-mobilizing activity was determined only in 3 out of 20 strains of Rhizobium spp. – with a low solubilization index (IS). On the contrary, all strains of Pseudomonas sp. showed a positive result, and the highest IS was in Pseudomonas sp. OBA 2.4.1 and GOR 4.17. The highest growth activity under stressful conditions was shown by 4 strains of Pseudomonas spp.: OBA 2.4.1, OBA 2.9, 4.17 and STA 3, their growth was noticeably inhibited with an increase in the concentration of glyphosate in the medium to 10.0 mg/ml. The growth activity of Rhizobium spp. strains was characterized as average. When growing on a medium with NiCl2, Pseudomonas strains sp. 65 HM and 67 HM grew to a concentration of 9 mM NiCl2 in the medium, at a concentration of 11 mM, strain 67 HM gave growth in the form of single colonies. These strains were isolated from soil samples taken from sites contaminated with chemical effluents. It is possible that nickel chlorides were already present in such soil in high concentrations exceeding the norm, that is why these strains had such high resistance to nickel ions. Thus, Rhizobium sp. strains did not have the most active PGPR properties, but different strains of Pseudomonas sp. showed high resistance to glyphosate and nickel chloride. Thus, Pseudomonas sp. they demostrated their high ability to adapt to stressful conditions. It is such PGPR bacteria (Plant Growth Promoting Rhizo bacteria) that can be considered as biological agents to increase the efficiency of bioremediation of agricultural soils.

Heat shock protein 70 enhances viral replication by stabilizing Senecavirus A nonstructural proteins L and 3D

Senecavirus A (SVA) is an emerging pathogen that causes idiopathic vesicular infections in pig herds, posing a potential threat to their production performance. Heat shock protein 70 (Hsp70) is a molecular chaperone that plays an important role in host homeostasis under both physiological and stress conditions. However, the effects of Hsp70 on SVA infection and its underlying regulatory mechanisms remain unclear. Here, we confirmed that Hsp70 expression promotes SVA infection, as evidenced by the expression of viral proteins, viral titers, and the number of rSVA-eGFP-infected cells. This positive regulatory role of Hsp70 is mainly involved in post-entry stages of SVA. Viral proteins that interacted with Hsp70 were screened, and co-immunoprecipitation (co-IP) shows an interaction between Hsp70 and SVA L and 3D proteins. Subsequently, we determined that the expression of Hsp70 is beneficial for the stability of the SVA L and 3D proteins. Additionally, the substrate-binding domain (SBD) of Hsp70 plays an important role in the interaction between Hsp70 and SVA L or 3D proteins; and the deletion of this domain results in the loss of the stabilizing effect of Hsp70 on SVA L and 3D proteins and the positive regulatory effect of Hsp70 on SVA replication. These results reveal that Hsp70 promotes SVA infection by stabilizing viral L and 3D proteins and provides a strategy for preventing and controlling SVA infection.

Genetically Encoded Biosensor HyPer as a Tool for Quantification of Intracellular Hydrogen Peroxide Concentrations

This mini-reviewsystematizes information on methods for quantitative assessment of intracellular hydrogenperoxide concentration based on the use of a genetically encodedperoxide sensor HyPer. Two approaches are being considered: 1) calibrationof the biosensor using exogenous hydrogen peroxide, based on assessingthe rate of peroxide penetration into cells and intracellular peroxidaseactivity; 2) direct determination of the intracellular peroxide content, basedon measuring the level of oxidation of the biosensor, theoxidation reaction constant and the reduction reaction constant of HyPerin the cells. The use of these methods makes itpossible to solve a wide range of tasks in cellularredox biology—to determine the range of physiological anddamaging concentrations of hydrogen peroxide in cells, to evaluate theeffectiveness of the antioxidant defense system in various cellular compartmentsunder conditions of oxidative stress, to determine the contribution ofvarious enzymatic systems to the peroxidase activity of cells, andto characterize antioxidant defense systems in various biological contexts (inthe process of cellular senescence, differentiation, reprogramming, during the developmentof pathologies). The described methods can be adapted for othergenetically encoded hydrogen peroxide biosensors.

Creep rupture and microstructural analysis of dissimilar welded joints of P92 steel and Alloy 617

Advanced ultra-supercritical plants are recognized for their efficiency and effectiveness in energy production, particularly when operating at elevated steam temperatures (700–720 °C). High-temperature components within these plants, including turbines, pipes, headers, and tubes, typically employ nickel-based alloys like Alloy 617, renowned for their outstanding resistance to corrosion and oxidation. Nevertheless, lower-temperature components (below 620 °C) frequently use less expensive ferritic-grade steels like P91 and P92. Welding these disparate materials balanced the plant’s performance and cost-effectiveness. This study focuses on the creep rupture behaviour of a dissimilar welded joint made through a gas tungsten arc welded joint between P92 steel and Alloy 617, utilizing a Ni-based Inconel 617 filler, at a test temperature of 650 °C under a stress of 140 MPa. A light microscope and a field emission scanning electron microscope were used for microstructural study. The investigation looks at how creep ruptures happen and how the microstructure changes inside the DWJ, and microhardness testing to comprehensively assess the joint’s performance under specific stress and temperature conditions. At 140 MPa and 650 °C, the sample demonstrated a creep rupture time of 54.5 h.

Mycoremediation of heavy metals by Curvularia lunata from Buckingham Canal, Neelankarai, Chennai.

The spread and mobilization of toxic heavy metals in the environment have increased to a harmful level in recent years as a result of the fast industrialization occurring all over the world to meet the demands of a rising population. This research aims to analyze and evaluate the mycoremediation abilities of fungal strains that exhibit tolerance to heavy metals, gathered from water samples at Buckingham Canal, Neelankarai, Chennai. Water samples were examined for heavy metal analysis, and the highest toxic heavy metals, Zn, Pb, Mn, Cu, and Cr, were recorded. Three fungal strains were isolated and named EBPL1000, EBPL1001, and EBPL1002 were selected by primary screening (100ppm) for further studies. Out of three fungal isolates, EBPL1000 grew in all five heavy metal concentrations and showed 2100ppm as the highest Maximum Tolerance Concentration toward Lead, 2000ppm tolerance in Zinc and Manganese, 1700ppm in Chromium, and 1500ppm in copper, respectively. The fungal isolate EBPL1000 was identified as Curvularia lunata with 100% percentage identity and query coverage. The Biosorption result reveals that lead is the highest biosorbed heavy metal with 79.99% at 100ppm concentration while copper is the lowest biosorbed with 24.11% heavy metal at 500ppm concentration. The uptake of Manganese by Curvularia lunata biomass was the highest (5.64mg/g) of all heavy metal's uptake at 100ppm concentration. The lowest uptake of heavy metals was copper (0.43mg/g) at 500ppm concentration, and the growth profile study under heavy metals stress conditions shows the order of Pb > Mn > Zn > Cr > Cu at 60h of time intervals at 100ppm concentration. In addition to the research, FTIR analysis and Molecular Docking studies provide credence to the idea that Curvularia lunata has high biosorption potential and uptake or removal of toxic heavy metals at low cost and in an eco-friendly way from the contaminated environment.

Phenylmercury stress induces root tip swelling through auxin homeostasis disruption

We previously reported that in Arabidopsis, the phytochelatin-mediated metal-detoxification machinery is also essential for organomercurial phenylmercury (PheHg) tolerance. PheHg treatment causes severe root growth inhibition in cad1-3, an Arabidopsis phytochelatin-deficient mutant, frequently accompanied by abnormal root tip swelling. Here, we examine morphological and physiological characteristics of PheHg-induced abnormal root tip swelling in comparison to Hg(II) stress and demonstrate that auxin homeostasis disorder in the root is associated with the PheHg-induced root tip swelling. Both Hg(II) and PheHg treatments severely inhibited root growth in cad1-3 and simultaneously induced the disappearance of starch-containing plastid amyloplasts in columella cells. However, further confocal imaging of the root tip revealed distinct effects of Hg(II) and PheHg toxicity on root cell morphology. PheHg treatment suppressed most major genes involved in auxin homeostasis, whereas these expression levels were up-regulated after 24 h of Hg(II) treatment. PheHg-triggered suppression of auxin transporters PIN1, PIN2, and PIN3 as GFP-fusion proteins was observed in the root tip, accompanied by an auxin reporter DR5rev::GFP signal reduction. Supplementation of indole-3-acetic acid (IAA) drastically canceled the PheHg-induced root swelling, however, Hg(II) toxicity was not mitigated by IAA. The presented results show that the collapse of auxin homeostasis especially in root tips is a cause for the abnormal root tip swelling under PheHg stress conditions.

Mitochondrial unfolded protein response-dependent β-catenin signaling promotes neuroendocrine prostate cancer.

The mitochondrial unfolded protein response (UPRmt) maintains mitochondrial quality control and proteostasis under stress conditions. However, the role of UPRmt in aggressive and resistant prostate cancer is not clearly defined. We show that castration-resistant neuroendocrine prostate cancer (CRPC-NE) harbored highly dysfunctional oxidative phosphorylation (OXPHOS) Complexes. However, biochemical and protein analyses of CRPC-NE tumors showed upregulation of nuclear-encoded OXPHOS proteins and UPRmt in this lethal subset of prostate cancer suggestive of compensatory upregulation of stress signaling. Genetic deletion and pharmacological inhibition of the main chaperone of UPRmt heat shock protein 60 (HSP60) reduced neuroendocrine prostate cancer (NEPC) growth in vivo as well as reverted NEPC cells to a more epithelial-like state. HSP60-dependent aggressive NEPC phenotypes was associated with upregulation of β-catenin signaling both in cancer cells and in vivo tumors. HSP60 expression rendered enrichment of aggressive prostate cancer signatures and metastatic potential were inhibited upon suppression of UPRmt. We discovered that UPRmt promoted OXPHOS functions including mitochondrial bioenergetics in CRPC-NE via regulation of β-catenin signaling. Mitochondrial biogenesis facilitated cisplatin resistance and inhibition of UPRmt resensitizes CRPC-NE cells to cisplatin. Together, our findings demonstrated that UPRmt promotes mitochondrial health via upregulating β-catenin signaling and UPRmt represents viable therapeutic target for NEPC.

Continuum-Particle Coupling for Polymer Simulations.

We report a concurrent hybrid multiscale simulation method, in which a particle domain is coupled with a surrounding continuum domain. The particle domain consists of a coarse-grained model of poly(lactic acid) and the continuum domain is treated using the finite element method. The coarse-grained model is derived from an atomistic model, using the iterative Boltzmann inversion scheme. The particle- and the finite element-domains overlap in a bridging domain through anchor points. In this coupling, the information passes back and forth between the high- and the low-resolution domains, effectively bridging the gap between the nano and macro-scales. This scheme is employed to simulate the coupled particle-continuum domains under both stochastic and semistochastic boundary conditions. While the anchor points keep the volume of the particle domain fixed in the former case, there is no anchor point in the planes normal to the periodic direction, in the latter case. The stress-strain behavior of polymer under both stochastic and semistochastic boundary conditions is investigated and the results are compared with those calculated from pure finite element reference simulations. Furthermore, the stress-strain relationship for the coupled system under the semistochastic boundary conditions is examined under plane stress and plane strain conditions, and the results are compared with those of pure finite element reference simulations. The hybrid particle-continuum method reproduces the pure finite element simulation results well.

Water use efficiency and grain yield of water stressed-field grown triticale as affected by combined application of biochar and biological fertilizer

Water stress poses a significant constraint on crop productivity in arid regions. A 2-year field experiment was conducted using a split-factorial layout within a randomized complete block (RCB) design to determine whether the combination of Azospirillum brasilense and Pseudomonas fluorescens (plant growth-promoting rhizobacteria [PGPRs]) with organic matter (OM) can mitigate the negative impacts of water stress on the grain yield of triticale (×Triticosecale Wittmack), as well as on water use efficiency for grain (WUEg) and biomass (WUEb). Irrigation treatments, including full irrigation (IRN) and post-milking deficit irrigation (IRD), were assigned to the main plots. Subplots were allocated to different OM sources (no OM, wheat residue, and its biochar) and nitrogen-phosphorus (N-P) sources, viz: chemical N-P fertilizer and integrated N-P fertilizer (50% chemical N-P fertilizer combined with PGPRs). Results indicated that IRD led to a significant decrease in grain yield (60.1%) and, ultimately, WUEg (43.4%) without OM application. However, using biochar resulted in the lowest reductions in these traits (41.1% and 14.6%, respectively) compared to the other OM treatments. The application of integrated N-P fertilizer resulted in an increase in grain yield, WUEg, and WUEb, across all types of OM compared to chemical N-P fertilizer. Notably, the most substantial improvements were observed with the application of biochar, which enhanced grain yield, WUEg, and WUEb by 24.5%, 27.7%, and 18.6%, respectively. Additionally, the application of integrated N-P fertilizer mitigated the decline in average grain weight, a crucial factor influencing the grain yield of triticale, under post-milking water stress conditions. Finally, integrated N-P fertilizer in conjunction with biochar is recommended for arid regions facing irrigation water restrictions during the grain-filling stage of triticale.

Changes in Photosynthetic Efficiency, Biomass, and Sugar Content of Sweet Sorghum Under Different Water and Salt Conditions in Arid Region of Northwest China

Sweet sorghum (Sorghum bicolor L. Moench) has significant cultivation potential in arid and saline–alkaline regions due to its drought and salt tolerance. This study aims to evaluate the mechanisms by which increased soil salinity and reduced irrigation affect the growth, aboveground biomass, and stem sugar content of sweet sorghum. A two-year field experiment was conducted, with four salinity levels (CK: 4.17 dS/m, S1: 5.83 dS/m, S2: 7.50 dS/m, and S3: 9.17 dS/m) and three irrigation levels (W1: 90 mm, W2: 70 mm, and W3: 50 mm). The results showed that increased salinity and reduced irrigation significantly reduced both the emergence rate and aboveground biomass, with the decreases in the emergence rate ranging from 11.0% to 36.2% and the reductions in the aboveground biomass ranging from 15.9% to 43.8%. Additionally, increased soil salinity led to reductions in stem sugar content of 6.3% (S1), 8.8% (S2), and 12.8% (S3), respectively. The results also indicated that photosynthetic efficiency, including the net photosynthetic rate (Pn), stomatal conductance (Gs), and chlorophyll content (SPAD), was significantly hindered under increased water and salt stress, with the Pn decreasing by up to 50.4% and the SPAD values decreasing by up to 36.3% under the highest stress conditions. These findings underscore the adverse impacts of increased soil salinity and reduced irrigation on sweet sorghum’s growth, photosynthetic performance, and sugar accumulation, offering critical insights for optimizing its cultivation in arid and saline environments.

The AREB transcription factor SaAREB6 promotes drought stress-induced santalol biosynthesis in sandalwood

Abstract Sandalwood (Santalum album), a culturally significant and economically valuable horticultural species, is renowned for its heartwood and essential oils enriched with sesquiterpene compounds such as santalol. Despite progress in elucidating the biosynthetic pathway of these valuable metabolites, the transcriptional regulation of this process, particularly under abiotic stress conditions, remains largely unexplored. Under drought conditions, we observed a marked increase in SaAREB6 expression, paralleled by elevated levels of santalols. Moreover, we identified SaCYP736A167, a cytochrome P450 monooxygenase gene, as a direct target of SaAREB6. Using electrophoretic mobility shift assays (EMSAs), microscale thermophoresis assays (MSTs) and dual luciferase assays (DLAs), we validated the precise and specific interaction of SaAREB6 with the promoter region of SaCYP736A167. This interaction leads to the upregulation of SaCYP736A167, which in turn catalyzes the final steps in the conversion of sesquiterpene precursors to santalols, thereby reinforcing the connection between SaAREB6 activity and increased santalol production during drought. Collectively, our work illuminates the previously uncharacterized role of SaAREB6 in orchestrating a transcriptional regulation that facilitates drought-induced santalol biosynthesis in sandalwood, presenting opportunities for genetic engineering strategies to improve heartwood and essential oil yields in this economically vital species.

The effects of emotional distress on attentional bias toward cigarette warnings according to smokers' anxiety levels

Anxiety is related with the substance use, including cigarette smoking. Avoidance is one of the strategies smokers with anxiety adopt to manage negative affect, which can be contradictory to a strategy of cigarette warnings that is used to induce negative affect to change smoking behaviors. Therefore, this study examined whether smokers' anxiety levels decrease their attentional biases toward cigarette warnings, especially in response to emotional distress. High-anxiety (n = 60) and low-anxiety (n = 60) smokers were randomly assigned to either a stress condition that utilized the PASAT-C task (Paced Auditory Serial Addition Task-Computer version) or a controlled condition. With the eye-tracking task that involved viewing 8 visual stimuli of cigarette packs composed of warnings and brandings, time to first fixation and fixation duration to warnings compared to brandings were measured both pre and post conditions. The results revealed that high-anxiety smokers detected warnings faster after stress conditions while low-anxiety smokers showed the consistent time to first fixation on warnings. In terms of fixation durations, high-anxiety smokers showed hypervigilance toward warnings that are considered to be a threat, but low-anxiety smokers showed avoidance under stress conditions, particularly toward social-focused warnings. These results indicate that high-anxiety smokers are more vulnerable to emotional distress and have an attentional bias toward fear appeals. Despite hypervigilance, they had greater psychological reactance toward warnings that the conflict between avoidance and hypervigilance might have contributed to, so the effectiveness of fear appeals may be limited regardless of the increased fixation duration.

Short‐Term Responses of Native (Perna viridis, Linnaeus 1758) and Non‐Native (Mytella strigata, Hanley 1843) Mussels to Independent and Combined Effects of Lowered pH Level and Elevated Temperature

ABSTRACTChanges in environmental conditions can influence the success of marine biological invasions. This study assessed the independent and combined acute short‐term effects of increased temperature (OW) and lowered pH (OA) simulating future ocean conditions on a native, Perna viridis, and non‐native, Mytella strigata, mussel species. There were four treatment combinations: Future (combination of ocean warming and ocean acidification), Ambient conditions, ocean acidification (OA), and ocean warming (OW). Survival and byssus thread regeneration in all treatments were measured daily for 7 days, while net calcification rate was calculated from the start and end of the experiment. Net calcification rate (NCR) was lowest under OA treatment. Likewise the low total alkalinity at the start of the experiment under OA suggests that the mussels experienced greater physiological stress. The higher survival rate of green mussels and the increase in the byssus regeneration rate over time in all treatments demonstrated that it can acclimate better to acute short‐term temperature and pH stress. The very low survival of M. strigata in OA compared to other treatments indicates its high sensitivity to low pH stress. However, surviving charru individuals maintained high byssus thread regeneration in all treatments. Overall, results suggest that M. strigata may not displace the native green mussels', P. viridis, higher tolerance to acute short‐term exposure to elevated temperatures and low pH, but can co‐exist in lower densities. This is the first study to compare the short‐term physiological responses of a sympatric non‐native and native mussel species under experimentally induced stress conditions. Longer‐term studies on the population dynamics of these species are essential to assess the potential success of these species under changing and variable environmental conditions.

The Effects of Elite Puroindoline Gene Alleles on the Kernel Hardness of Chinese Winter Wheat

Kernel hardness (KH) is a significant factor that influences wheat quality. In order to gain a better understanding of KH profiles and the effects of its associated genes in Chinese wheat cultivars growing under normal and latest stage drought stress conditions, 206 wheat cultivars were examined. The kernel hardness index (KHI) was measured by utilizing a single kernel hardness tester, and allelic variations of the puroindoline genes regulating KH were detected using KASP markers. The hardness test indicated that 121 (58.7%) were classified as hard wheat, 39 (18.9%) as soft wheat, and 46 (22.3%) as mixed wheat. Genotypic analysis revealed that 10 cultivars (4.9%) carried the superior Pina-D1b allele, 143 cultivars (69.4%) possessed the Pinb-D1b allele, representing the main allele for hard wheat, and 45 cultivars (21.8%) contained the Pinb-B2b allele. An analysis of the cumulative effect across five gene loci indicated that among the tested materials, none contained all five excellent gene loci simultaneously. However, materials with combinations of two, three, or four excellent gene loci exhibited significantly higher KHI values compared to those with zero or only one excellent locus. This finding suggests that the accumulation of excellent gene loci can enhance KH. Among various allelic combinations, Pina-D1 + M0159 displayed remarkably higher KH values than the others. Conversely, Pinb-D1 + M0380 exhibited significantly lower KH values. Drought stress during the late growth stage of wheat could enhance KH.

Grafting and Inoculation of Grafted Plants With Bacillus amyloliquefaciens Enhances Biotic and Abiotic Stress Tolerance in Organic Tomato

Biotic and abiotic stress factors pose significant challenges to organic tomato production in Alabama and the southeastern United States. High temperature, drought, soil, and foliar-borne diseases have rendered it exceedingly difficult for organic tomato growers in Alabama to produce profitable crops. Our objective was to evaluate plant response to imposed biotic (Verticillium dahliae) and abiotic (drought) stress in the popular tomato variety ‘Roma’ through grafting unto the resistant rootstock ‘Maxifort’, and the incorporation of the plant growth-promoting rhizobacterium (PGPR) B. amyloliquefaciens, to mitigate challenges posed by these stress factors. The research was conducted in a greenhouse in north Alabama where both soilborne pathogens (V. dahliae) and drought stress treatments were applied. The experimental design was a split plot with 4 main plots (Grafting, PGPR, Grafting + PGPR, and Control) and 3 subplots (drought, pathogen, and control) treatments with 4 replications. B. amyloliquefaciens was applied in the rhizosphere of grafted and non-grafted plants at 1 × 108 CFU/ml/plant. Pathogen-treated plants were also inoculated with V. dahliae at 1 × 105 propagules/ml. The study revealed that grafting, and grafting + B. amyloliquefaciens caused a significant increase in stem girth, plant biomass, early flowering, and fruiting of tomatoes compared to the non-grafted and control treatments. Integrating grafting and PGPR could be beneficial in enhancing plant resilience and performance under biotic and abiotic stress conditions.