Phosphate solubilizing bacteria, Pseudomonas aeruginosa, improve the growth and yield of groundnut (Arachis hypogaea L.).

For agricultural safety and sustainability, instead of synthetic fertilizers the eco-friendly and inexpensive biological applications include members of plant-growth-promoting rhizobacteria (PGPR) genera, Pseudomonas spp. will be an excellent alternative option to bioinoculants as they do not threaten the soil biota. The effect of phosphate solubilizing bacteria (PSB) Pseudomonas aeruginosa (MK 764942.1) on groundnuts' growth and yield parameters was studied under field conditions. The strain was combined with a single super phosphate and tested in different combinations for yield improvement. Integration of bacterial strain with P fertilizer gave significantly higher pod yield ranging from 7.36 to 13.18% compared to plots where sole inorganic fertilizers were applied. Similarly, the combined application of PSB and inorganic P fertilizer significantly influenced plant height and number of branches compared to sole. However, a higher influence of phosphorous application (both PSB and P fertilizer) observed both nodule dry weight and number of nodules. Combined with single super phosphate (100% P) topped in providing better yield attributing characters (pod yield, haulm yield, biomass yield, 1000 kernel weight, and shelling percentage) in groundnut. Higher oil content was also recorded with plants treated with Pseudomonas aeruginosa combined with single super phosphate (SSP) (100% P). Nutrients like nitrogen (N), phosphorous (P), and potassium (K) concentrations were positively influenced in shoot and kernel by combined application. In contrast, Ca, Mg, and S were found to be least influenced by variations of Phosphorous. Plants treated with Pseudomonas aeruginosa and lower doses of SSP (75% P) recorded higher shoot and kernel P. We found that co-inoculation with PSB and SSP could be an auspicious substitute for utilizing P fertilizer in enhancing yield and protecting nutrient concentrations in groundnut cultivation. Therefore, PSB can be a good substitute for bio-fertilizers to promote agricultural sustainability.

Taxonomic and functional changes in wheat rhizosphere microbiome caused by imidazoline-based herbicide and genetic modification.

Genetically modified (GM) crop cultivation has received a lot of attention in recent years due to the substantial public debate. Consequently, an in-depth investigation of excessively used GM herbicide-tolerant crops is a vital step for the biosafety of genetically modified plants. Several studies have been conducted to study the impact of transgenic GM crops on soil microbial composition; however, research into the effects of non-transgenic GM crops is inadequate. In the current work, high-throughput sequencing was used to evaluate the impact of the acetolactate synthase (ALS)-mutant (WK170B), its control (YN19B), and the imazamox (IM) herbicide on the wheat rhizobiome. Under normal growth conditions, our work revealed a minimal impact of ALS-mutant WK170B on the rhizosphere microbiome compared to the control YN10B, except for some cyanobacterial microorganisms that showed a significant increase in abundance. This suggests that the gene mutation could potentially have a beneficial impact on the bacterial communities present in the rhizosphere. Following IM exposure, taxonomic analysis revealed a significant reduction in the relative abundance of Ralstonia pickettii and an unidentified member of the genus Ancylothrix 8PC. Analyses of both alpha and beta diversity revealed a statistically significant increase in both microbial richness and species diversity. IM-induced relative abundance modulation was also evident through Linear discriminant analysis Effect Size (LEfSe), MetaStat, and heatmap analyses. The SIMPER analysis revealed that the microbial taxa Massilia, Limnobacter, Hydrogenophaga, Ralstonia, Nitrospira, and Ramlibacter exhibited the highest vulnerability to IM exposure. The functional attributes analysis revealed that the relative abundance of genes associated with the extracellular matrix-receptor interaction, which is responsible for structural support and stress response, increased significantly following IM exposure. Collectively, our study identifies key microbial taxa in the wheat rhizobiome that are sensitive to IM herbicides and provides a foundation for assessing the environmental risks associated with IM herbicide use.

Correlated changes in stress resistance and biochemical parameters in response to long-term protein restriction in Drosophila melanogaster.

Studies in fruit flies, Drosophila melanogaster, have observed considerable variation in the effect of dietary protein restriction (PR) on various fitness traits. In addition, not only are there inconsistent results relating lifespan to stress resistance, but also the long-term effects of PR are unexplored. We study PR implementation across generations (long term) hypothesizing that it will be beneficial for fitness traits, stress resistance and storage reserves due to nutritional plasticity transferred by parents to offspring in earlier Drosophila studies. By imposing two concentrations of PR diets (50% and 70% of control protein) from the pre-adult and adult (age 1 day) stages of the flies, we assessed the stage-specific and long-term effect of the imposed PR. All long-term PR flies showed increased resistance against the tested stressors (starvation, desiccation, H2O2-induced oxidative stress). In addition, we also found long-term PR-induced increased stress resistance across generations. The PR flies also possessed higher protein and triglyceride (TG) content, reduced glucose and unaffected glycogen levels. We also assayed the effect of returning the PR flies to control (AL) food for a single generation and assessed their biochemical parameters to witness the transient PR effect. It was seen that TG content upon reversal was similar to AL flies except for PRI70 males; however, the glucose levels of PR males increased, while they were consistently lower in females. Taken altogether, our study suggests that long-term PR implementation contributes to increased stress resistance and was found to influence storage reserves in D. melanogaster.

Plastid HSP90C C-terminal extension region plays a regulatory role in chaperone activity and client binding.

HSP90Cs are essential molecular chaperones localized in the plastid stroma that maintain protein homeostasis and assist the import and thylakoid transport of chloroplast proteins. While HSP90C contains all conserved domains as an HSP90 family protein, it also possesses a unique feature in its variable C-terminal extension (CTE) region. This study elucidated the specific function of this HSP90C CTE region. Our phylogenetic analyses revealed that this intrinsically disordered region contains a highly conserved DPW motif in the green lineages. With biochemical assays, we showed that the CTE is required for the chaperone to effectively interact with client proteins PsbO1 and LHCB2 to regulate ATP-independent chaperone activity and to effectuate its ATP hydrolysis. The CTE truncation mutants could support plant growth and development reminiscing the wild type under normal conditions except for a minor phenotype in cotyledon when expressed at a level comparable to wild type. However, higher HSP90C expression was observed to correlate with a stronger response to specific photosystem II inhibitor DCMU, and CTE truncations dampened the response. Additionally, when treated with lincomycin to inhibit chloroplast protein translation, CTE truncation mutants showed a delayed response to PsbO1 expression repression, suggesting its role in chloroplast retrograde signaling. Our study therefore provides insights into the mechanism of HSP90C in client protein binding and the regulation of green chloroplast maturation and function, especially under stress conditions.

Antioxidant and Stress Resistance Properties of Flavonoids from Chinese Sea Buckthorn Leaves from the Qinghai-Tibet Plateau.

The unique ecological environment of the Qinghai-Tibetan Plateau has endowed Chinese sea buckthorn leaves with rich bioactivities. In this study, we investigated the bioactivity and stress resistance mechanisms of flavonoids derived from Chinese sea buckthorn leaves (FCL) native to the Qinghai-Tibet Plateau. Our analysis identified a total of 57 flavonoids, mainly flavonol glycosides, from FCL, of which 6 were novel flavonoids. Isorhamnetin glycosides, quercetin glycosides and kaempferol glycosides were the three most dominant classes of compounds in FCL. In particular, isorhamnetin-3-O-glucoside-7-O-rhamnoside emerged as the most abundant compound. Our results showed that FCL possesses potent antioxidant properties, as evidenced by its ability to effectively scavenge DPPH free radicals and demonstrate ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) levels comparable to Trolox, a well-known antioxidant standard. Furthermore, FCL showed remarkable efficacy in reducing reactive oxygen species (ROS) levels and malondialdehyde (MDA) levels while enhancing the activities of key antioxidant enzymes, namely superoxide dismutase (SOD) and catalase (CAT), in Caenorhabditis elegans, a widely used model organism. Mechanistically, we elucidated that FCL exerts its stress resistance effects by modulating of transcription factors DAF-16 and HSF-1 within the insulin/insulin-like growth factor-1 signaling pathway (IIS). Activation of these transcription factors orchestrates the expression of downstream target genes including sod-3, ctl-1, hsp16.2, and hsp12.6, thus enhancing the organism's ability to cope with stressors. Overall, our study highlights the rich reservoir of flavonoids in Chinese sea buckthorn leaves as promising candidates for natural medicines, due to their robust antioxidant properties and ability to enhance stress resistance.

RNase R Affects the Level of Fatty Acid Biosynthesis Transcripts Leading to Changes in membrane Fluidity.

Previous studies on RNase R have highlighted significant effects of this ribonuclease in several processes of Streptococcus pneumoniae biology. In this work we show that elimination of RNase R results in overexpression of most of genes encoding the components of type II fatty acid biosynthesis (FASII) cluster. We demonstrate that RNase R is implicated in the turnover of most of transcripts from this pathway, affecting the outcome of the whole FASII cluster, and ultimately leading to changes in the membrane fatty acid composition. Our results show that the membrane of the deleted strain contains higher proportion of unsaturated and long-chained fatty acids than the membrane of the wild type strain. These alterations render the RNase R mutant more prone to membrane lipid peroxidation and are likely the reason for the increased sensitivity of this strain to detergent lysis and to the action of the bacteriocin nisin. Reprogramming of membrane fluidity is an adaptative cell response crucial for bacterial survival in constantly changing environmental conditions. The data presented here is suggestive of a role for RNase R in the composition of S. pneumoniae membrane, with strong impact on pneumococci adaptation to different stress situations.

Evolutionary engineering and molecular characterization of cobalt-resistant Rhodobacter sphaeroides.

With its versatile metabolism including aerobic and anaerobic respiration, photosynthesis, photo-fermentation and nitrogen fixation, Rhodobacter sphaeroides can adapt to diverse environmental and nutritional conditions, including the presence of various stressors such as heavy metals. Thus, it is an important microorganism to study the molecular mechanisms of bacterial stress response and resistance, and to be used as a microbial cell factory for biotechnological applications or bioremediation. In this study, a highly cobalt-resistant and genetically stable R. sphaeroides strain was obtained by evolutionary engineering, also known as adaptive laboratory evolution (ALE), a powerful strategy to improve and characterize genetically complex, desired microbial phenotypes, such as stress resistance. For this purpose, successive batch selection was performed in the presence of gradually increased cobalt stress levels between 0.1-15 mM CoCl2 for 64 passages and without any mutagenesis of the initial population prior to selection. The mutant individuals were randomly chosen from the last population and analyzed in detail. Among these, a highly cobalt-resistant and genetically stable evolved strain called G7 showed significant cross-resistance against various stressors such as iron, magnesium, nickel, aluminum, and NaCl. Growth profiles and flame atomic absorption spectrometry analysis results revealed that in the presence of 4 mM CoCl2 that significantly inhibited growth of the reference strain, the growth of the evolved strain was unaffected, and higher levels of cobalt ions were associated with G7 cells than the reference strain. This may imply that cobalt ions accumulated in or on G7 cells, indicating the potential of G7 for cobalt bioremediation. Whole genome sequencing of the evolved strain identified 23 single nucleotide polymorphisms in various genes that are associated with transcriptional regulators, NifB family-FeMo cofactor biosynthesis, putative virulence factors, TRAP-T family transporter, sodium/proton antiporter, and also in genes with unknown functions, which may have a potential role in the cobalt resistance of R. sphaeroides.

Wheat lesion mimic homology gene TaCAT2 enhances plant resistance to biotic and abiotic stresses.

Lesion mimic mutants (LMMs) refer to the spontaneous formation of disease-like spots on leaves without any obvious pathogen infection. The LMM genes can regulate plant immunity, thus promoting the defense of crops against pathogens. However, there is a lack of systematic understanding of the regulatory mechanism of LMMs in wheat. This study identified a wheat LMM TaCAT2, a homolog of the Arabidopsis CAT2. The prediction of the cis-regulatory element revealed that TaCAT2 was involved in the response of plants to various hormones and stresses. RT-qPCR analysis indicated that TaCAT2 was significantly up-regulated by NaCl, drought, and Fusarium graminearum infection. Fluorescence microscopy showed that the TaCAT2 was localized to the peroxisome. Overexpression of TaCAT2 enhanced plant resistance to Phytophthora infestation and F. graminearum by constitutionally activating SA and JA pathways. VIGS of TaCAT2 enhanced the sensitivity of wheat to F. graminearum. Further, TaCAT2 enhanced stress resistance by scavenging the excessive ROS and increasing the activities of antioxidative enzymes. This study lays the basis for the functional identification of TaCAT2 and its applicability in the disease resistance of wheat.

Genome-wide characterization of drought-responsive long non-coding RNAs in sorghum (Sorghum bicolor).

Drought stress strongly affects crop yield. Although knowledge of long non-coding RNAs (lncRNAs) has been updated continuously and rapidly, information about lncRNAs in drought resistance regulation is extremely limited in sorghum. Here, lncRNA-sequencing was performed with seedlings of a sorghum cultivar (Jinza29) under three water control treatments to investigate the mechanism of lncRNAs responsible for drought resistance in sorghum. A total of 377 differentially expressed lncRNAs (DElncRNAs) were identified. We also predicted 4322 and 2827 transcripts as potential cis-target and trans-target genes for drought-responsive lncRNAs, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that those target genes exhibited marked enrichment into "oxidoreductase activity", "signal transducer activity", "DNA repair", "photosynthesis", "glutathione metabolism", and "phenylpropanoid biosynthesis" and other terms associated with abiotic stress resistance. Moreover, several lncRNAs were estimated to modulate the expression of other genes related to stress response and photosynthetic carbon metabolism. Additionally, we found 107 DElncRNAs that might be candidate target mimics for 56 miRNAs. LncRNAs play important roles in drought adaptation of sorghum through interacting with protein-encoding genes. The obtained results provided novel insights into the biological characteristics of lncRNAs and offered potential regulatory factors for genetically enhancing drought resistance in sorghum.

Influence of α-lipoic acid on longevity and stress resistance in Drosophila melanogaster fed with a high-fat diet.

Consumption of a high-fat diet is accompanied by the risks of obesity and early onset of age-associated complications for which dietary interventions are imperative to combat. α-lipoic acid has been shown to hinder diet-induced obesity and induce lifespan-extending efficacy in model organisms. In this study, α-lipoic acid was investigated for its efficacy in improving lifespan and stress resistance in the Canton-S strain of Drosophila melanogaster fed with a high-fat diet. Furthermore, as mating status significantly impacts survival in fruit flies, flies were reared in two experimental groups-group one, in which males and females were bred together, and group two, in which males and females were bred separately. In group one, α-lipoic acid improved the mean lifespan, reduced the fecundity of females, and reduced the mean body weight of flies at a dose range of 2-2.5 mM, respectively. In group two, α-lipoic acid improved the mean lifespan, reduced the fecundity of females, and reduced the mean body weight of flies at a dose range of 1-2.5 mM, respectively. Improved climbing efficiency was observed with α-lipoic acid at the dose range of 1.5-2.5 mM in flies of group one and 1-2.5 mM in flies of group two, respectively. Administration of α-lipoic acid improved resistance to oxidative stress in only female flies of group one at 2.5 mM, whereas in group two, both male and female flies exhibited enhanced resistance to oxidative stress with α-lipoic acid at a dose range of 2-2.5 mM, respectively. Male and female flies of only group one showed improved resistance to heat shock stress with α-lipoic acid at a dose range of 2-2.5 mM. Only female flies of group two exhibited a slight improvement in recovery time following cold shock with α-lipoic acid only at 2.5 mM. No significant change in resistance to starvation stress was observed with any dose of α-lipoic acid in either group of flies. To summarize, data from this study suggested a probable dose and gender-dependent efficacy of α-lipoic acid in flies fed with a high-fat diet, which was significantly influenced by the mating status of flies due to varied rearing conditions.

Stress resistance insights of 65 Listeria strains: Acidic, low temperature, and high salt environments.

Genetically, Listeria monocytogenes is closely related to non-L. monocytogenes (L. innocua, L. welshimeri, L. grayi, L. aquatica, and L. fleischimannii). This bacterium is well known for its resistance to harsh conditions including acidity, low temperatures, and high salt concentrations. This study explored the responses of 65 Listeria strains to stress conditions and characterized the prevalence of stress-related genes. The 65 Listeria strains were isolated from different environments and their viability was assessed in four different tests: independent tests for pH 3, 1 °C, and 5 % salt concentration and multiple resistance tests that combined pH 3, 1 °C, 5 % salt. From the data, the 65 strains were categorized into stress-resistant (56) or stress-sensitive groups (9), with approximately 4 log CFU/mL differences. The PCR assay analyzed the prevalence of two virulence genes prfA and inlA, and eight stress-related genes: three acid (gadB, gadC, and atpD), two low temperature (betL and opuCA) and three salt resistance genes (flaA, cysS, and fbp). Two low temperature (bet and opuCA) and salt resistance (fbp) genes were more prevalent in the stress-resistant strains than in the stress-sensitive Listeria group.

Mapping of flumioxazin tolerance in a snap bean diversity panel leads to the discovery of a master genomic region controlling multiple stress resistance genes.

Introduction: Effective weed management tools are crucial for maintaining the profitable production of snap bean (Phaseolus vulgaris L.). Preemergence herbicides help the crop to gain a size advantage over the weeds, but the few preemergence herbicides registered in snap bean have poor waterhemp (Amaranthus tuberculatus) control, a major pest in snap bean production. Waterhemp and other difficult-to-control weeds can be managed by flumioxazin, an herbicide that inhibits protoporphyrinogen oxidase (PPO). However, there is limited knowledge about crop tolerance to this herbicide. We aimed to quantify the degree of snap bean tolerance to flumioxazin and explore the underlying mechanisms. Methods: We investigated the genetic basis of herbicide tolerance using genome-wide association mapping approach utilizing field-collected data from a snap bean diversity panel, combined with gene expression data of cultivars with contrasting response. The response to a preemergence application of flumioxazin was measured by assessing plant population density and shoot biomass variables. Results: Snap bean tolerance to flumioxazin is associated with a single genomic location in chromosome 02. Tolerance is influenced by several factors, including those that are indirectly affected by seed size/weight and those that directly impact the herbicide's metabolism and protect the cell from reactive oxygen species-induced damage. Transcriptional profiling and co-expression network analysis identified biological pathways likely involved in flumioxazin tolerance, including oxidoreductase processes and programmed cell death. Transcriptional regulation of genes involved in those processes is possibly orchestrated by a transcription factor located in the region identified in the GWAS analysis. Several entries belonging to the Romano class, including Bush Romano 350, Roma II, and Romano Purpiat presented high levels of tolerance in this study. The alleles identified in the diversity panel that condition snap bean tolerance to flumioxazin shed light on a novel mechanism of herbicide tolerance and can be used in crop improvement.

Ethylene glycol is metabolized to ethanol and acetate and induces expression of bacterial microcompartments in Propionibacterium freudenreichii.

Ethylene glycol (EG, 1,2-ethanediol) is a two-carbon dihydroxy alcohol that can be derived from fermentation of plant-derived xylose and arabinose and which can be formed during food fermentations. Here we show that Propionibacterium freudenreichii DSM 20271 is able to convert EG in anaerobic conditions to ethanol and acetate in almost equimolar amounts. The metabolism of EG led to a moderate increase of biomass, indicating its metabolism is energetically favourable. A proteomic analysis revealed EG induced expression of the pdu-cluster, which encodes a functional bacterial microcompartment (BMC) involved in the degradation of 1,2-propanediol, with the presence of BMCs confirmed using transmission electron microscopy. Cross-examination of the proteomes of 1,2-propanediol and EG grown cells revealed PDU BMC-expressing cells have elevated levels of DNA repair proteins and cysteine biosynthesis proteins. Cells grown in 1,2-propanediol and EG also showed enhanced resistance against acid and bile salt-induced stresses compared to lactate-grown cells. Our analysis of whole genome sequences of selected genomes of BMC-encoding microorganisms able to metabolize EG with acetaldehyde as intermediate indicate a potentially broad-distributed role of the pdu operon in metabolism of EG. Based on our results we conclude EG is metabolized to acetate and ethanol with acetaldehyde as intermediate within BMCs in P. freudenreichii.

CAX control: multiple roles of vacuolar cation/H+ exchangers in metal tolerance, mineral nutrition and environmental signalling.

Plant vacuolar transporters, particularly CAX (Cation/H+ Exchangers) responsible for Ca2+/H+ exchange on the vacuole tonoplast, play a central role in governing cellular pH, ion balance, nutrient storage, metal accumulation, and stress responses. Furthermore, CAX variants have been employed to enhance the calcium content of crops, contributing to biofortification efforts. Recent research has uncovered the broader significance of these transporters in plant signal transduction and element partitioning. The use of genetically encoded Ca2+ sensors has begun to highlight the crucial role of CAX isoforms in generating cytosolic Ca2+ signals, underscoring their function as pivotal hubs in diverse environmental and developmental signalling networks. Interestingly, it has been observed that the loss of CAX function can be advantageous in specific stress conditions, both for biotic and abiotic stressors. Determining the optimal timing and approach for modulating the expression of CAX is a critical concern. In the future, strategically manipulating the temporal loss of CAX function in agriculturally important crops holds promise to bolster plant immunity, enhance cold tolerance, and fortify resilience against one of agriculture's most significant challenges, namely flooding.

The role of reactive oxygen species in regulation of the plasma membrane H +-ATPase activity in Masson pine (Pinus massoniana Lamb.) roots responding to acid stress.

To understand the role of reactive oxygen species (ROS) in regulation of the plasma membrane (PM) H+-ATPase in acid-stressed Masson pine roots, different acidity (pH 6.6 as the control, pH 5.6, and pH 4.6) of simulated acid rain (SAR) added with and without external chemicals [H2O2, enzyme inhibitors, and ROS scavenger] was prepared. After 30 days of SAR exposure, the plant morphological phenotype attributes, levels of cellular ROS and lipid peroxidation, enzymatic activities of antioxidants, PM nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and PM H+-ATPase activity in pine seedlings were measured. Compared to the control, the growth of pine seedlings exposed to SAR in the presence or absence of H2O2 was well-maintained, but the application of Na3VO4, 1,3-Dimethyl-2-thiourea, N, N-dimethylthiourea (DMTU), and diphenyleneiodonium chloride (DPI) caused a substantial growth inhibition. In addition, SAR exposure, SAR with H2O2 treatment, and SAR with Na3VO4 treatment increased the cellular H2O2 content, O2·- content, and malondialdehyde (MDA) content, while the use of DMTU and DPI lead to relatively low levels. Similarly, the enzymatic activities of antioxidants, PM NADPH oxidase, and PM H+-ATPase in acid stressed pine seedlings elevated with the increasing acidity. A significant stimulation of these enzymatic activities obtained from SAR with H2O2 treatment was observed, whereas which decreased obviously with the addition of Na3VO4, DMTU, and DPI (P < 0.05). Moreover, a positive correlation was found between plant morphological attributes and the PM H+-ATPase activity (P < 0.05). Besides, the PM H+-ATPase activity positively correlated with the cellular ROS contents and the enzymatic activities of antioxidants and PM NADPH oxidase (P < 0.05). Therefore, the PM H+-ATPase is instrumental in the growth of pine seedlings resisting to acid stress by enhancing its activity. The process involves the signaling transduction of cellular ROS and coordination with PM NADPH oxidase.

Mild to moderate drought stress reinforces the role of functional microbiome in promoting growth of a dominant forage species (Neopallasia pectinata) in desert steppe.

Background: Desert steppe ecosystems are prone to drought stress, which influences the ecological balance and sustainable development of grasslands. In addition to directly restrict plant growth, drought stress indirectly impacts plant fitness by altering the diversity and function of root-associated microbiomes. This begs the question of whether the functional microbiome of forage plants, represented by synthetic microbial communities (SynComs), can be leveraged to mitigate drought stress in desert steppes and promote the ecological restoration of these fragile ecosystems. Methods: A pot experiment was conducted to evaluate the role of SynComs in improving the plant growth and drought stress resistance of Neopallasia pectinata (Pall.) Poljak in desert steppe in Inner Mongolia, China. Six SynComs were derived from the rhizosphere and root endosphere of 12 dominant forage species in the desert steppe. Each SynCom comprised two to three bacterial genera (Bacillus, Protomicromonospora, and Streptomyces). We examined the capacities of different SynComs for nutrient solubilization, phytohormone secretion, and enzymatic activity. Results: Under no water stress (75% soil water holding capacity, WHC), single strains performed better than SynComs in promoting plant growth in terms of stem diameter, root length, and plant dry weight, with the greatest effects observed for Streptomyces coeruleorubidus ATCC 13740 (p < 0.05). However, under mild to moderate drought stress (55% and 35% WHC), SynComs outperformed single strains in enhancing plant biomass accumulation and inducing the production of resistance-related substances (p < 0.05). No significant effect of single strains and SynComs emerged under extreme drought stress (20% WHC). Conclusion: This study underscores the potential of SynComs in facilitating forage plants to combat drought stress in desert steppe. Mild to moderate drought stress stimulates SynComs to benefit the growth of N. pectinata plants, despite a soil moisture threshold (21% WHC) exists for the microbial effect. The use of SynComs provides a promising strategy for the ecological restoration and sustainable utilization of desert steppes by manipulating the functional microbiome of forage plants.

Functional Analysis of Stress Resistance of Bacillus cereus SCL10 Strain Based on Whole-Genome Sequencing.

A Gram-positive, rod-shaped, aerobic, motile, and spore-forming bacterium, designated SCL10, was isolated from Acaudina molpadioides exposure to Co-60 radiation. In this study, whole-genome sequencing was performed to identify the strain as Bacillus cereus and functional characterization, with a focus on stress resistance. The genome of the B. cereus SCL10 strain was sequenced and assembled, revealing a size of 4,979,182 bp and 5167 coding genes. The genes involved in biological functions were annotated by using the GO, COG, KEGG, NR, and Swiss-Prot databases. The results showed that genes related to alkyl hydroperoxide reductase (ahpC, ahpF), DNA-binding proteins from starved cells (dps), spore and biofilm formation (spoVG, spo0A, gerP), cold shock-like protein (cspC, cspE), ATP-dependent chaperone (clpB), and photolyase, small, acid-soluble spore protein (SASP) and DNA repair protein (recA, radD) could explain the stress resistance. These findings suggest that antioxidant activity, sporulation, biofilm formation, and DNA protection may be considered as the main resistance mechanisms under exposure to radiation in the B. cereus SCL10 strain.

Do the expected heatwaves pose a threat to lichens?: Linkage between a passive decline in water content in thalli and response to heat stress.

Being poikilohydric, lichens are inherently exposed to alternating desiccation and hydration cycles. They can exhibit extraordinary resistance to extreme temperatures in a dehydrated state but thermal thresholds for hydrated lichens are lower. The ability of the lichen Cetraria aculeata to recovery after high temperature treatment (40°C, 60°C) at different air humidity levels (relative humidity [RH]: <15%, 25%, 50%, 75%, ≅100%) was examined to find a linkage between passive dehydration of the lichen and its physiological resistance to heat stress. The response to heating was determined by measuring parameters related to photosynthesis and respiration after 2- and 24-h recovery. A higher RH level resulted in a slower decline in relative water content (RWC) in hydrated thalli. In turn, the stress resistance of active thalli depended on the ambient humidity and associated RWC reduction. Elevated temperature had a negative impact on bioenergetic processes, but only an unnatural state of permanent full hydration during heat stress resulted in a lethal effect. Hydrated lichen thalli heated at 40°C and 50% relative humidity (RH) tended to be least susceptible to stress-induced damage. Although atypical climatic conditions may lead lichens to lethal thresholds, the actual likelihood of deadly threat to lichens due to heat events per se is debatable.

The neuron-specific IIS/FOXO transcriptome in aged animals reveals regulatory mechanisms of cognitive aging.

Cognitive decline is a significant health concern in our aging society. Here, we used the model organism C. elegans to investigate the impact of the IIS/FOXO pathway on age-related cognitive decline. The daf-2 Insulin/IGF-1 receptor mutant exhibits a significant extension of learning and memory span with age compared to wild-type worms, an effect that is dependent on the DAF-16 transcription factor. To identify possible mechanisms by which aging daf-2 mutants maintain learning and memory with age while wild-type worms lose neuronal function, we carried out neuron-specific transcriptomic analysis in aged animals. We observed downregulation of neuronal genes and upregulation of transcriptional regulation genes in aging wild-type neurons. By contrast, IIS/FOXO pathway mutants exhibit distinct neuronal transcriptomic alterations in response to cognitive aging, including upregulation of stress response genes and downregulation of specific insulin signaling genes. We tested the roles of significantly transcriptionally-changed genes in regulating cognitive functions, identifying novel regulators of learning and memory. In addition to other mechanistic insights, a comparison of the aged vs young daf-2 neuronal transcriptome revealed that a new set of potentially neuroprotective genes is upregulated; instead of simply mimicking a young state, daf-2 may enhance neuronal resilience to accumulation of harm and take a more active approach to combat aging. These findings suggest a potential mechanism for regulating cognitive function with age and offer insights into novel therapeutic targets for age-related cognitive decline.

Inoculum source determines the stress resistance of electroactive functional taxa in biofilms: A metagenomic perspective.

The inoculum has a crucial impact on bioreactor initialization and performance. However, there is currently a lack of guidance on selecting appropriate inocula for applications in environmental biotechnology. In this study, we applied microbial electrolysis cells (MECs) as models to investigate the differences in the functional potential of electroactive microorganisms (EAMs) within anodic biofilms developed from four different inocula (natural or artificial), using shotgun metagenomic techniques. We specifically focused on extracellular electron transfer (EET) function and stress resistance, which affect the performance and stability of MECs. Community profiling revealed that the family Geobacteraceae was the key EAM taxon in all biofilms, with Geobacter as the dominant genus. The c-type cytochrome gene imcH showed universal importance for Geobacteraceae EET and was utilized as a marker gene to evaluate the EET potential of EAMs. Additionally, stress response functional genes were used to assess the stress resistance potential of Geobacter species. Comparative analysis of imcH gene abundance revealed that EAMs with comparable overall EET potential could be enriched from artificial and natural inocula (P > 0.05). However, quantification of stress response gene copy numbers in the genomes demonstrated that EAMs originating from natural inocula possessed superior stress resistance potential (196 vs. 163). Overall, this study provides novel perspectives on the inoculum effect in bioreactors and offers theoretical guidance for selecting inoculum in environmental engineering applications.