The effect of abiotic stresses on plant C:N:P homeostasis and their mitigation by silicon

In crop plants, various environmental stresses affect the balance of carbon, nitrogen, and phosphorus(C:N:P), leading to biochemical and physiological alterations and reductions in yield. Silicon(Si) is a beneficial element that alleviates plant stress. Most studies involving silicon have focused on physiological responses, such as improvements in photosynthetic processes, water use efficiency, and antioxidant defense systems. But recent research suggests that stressed plants facing either limited or excessive resources(water, light, nutrients, and toxic elements), strategically employ Si to maintain C:N:P homeostasis, thereby minimizing biomass losses. Understanding the role of Si in mitigating the impact of abiotic stresses on plants by regulating C:N:P homeostasis holds great potential for advancing sustainable agricultural practices in crop production. This review presents recent advances in characterizing the influence of environmental stresses on C:N:P homeostasis, as well as the role of Si in preserving C:N:P equilibrium and attenuating biological damage associated with abiotic stress. It underscores the beneficial effects of Si in sustaining C:N:P homeostasis and increasing yield via improved nutritional efficiency and stress mitigation.

Resistance mechanisms and reprogramming of microorganisms for efficient biorefinery under multiple environmental stresses

In the fermentation process of biorefinery,industrial strains are normally subjected to adverse environmental stresses,which leads to their slow growth,yield decline,a substantial increase in energy consumption,and other negative consequences,which ultimately seriously hamper the development of biorefinery.How to minimize the impact of stress on microorganisms is of great significance.This review not only reveals the damaging effects of different environmental stresses on microbial strains but also introduces commonly used strategies to improve microbial tolerance,including adaptive evolution,reprogramming of the industrial host based on genetic circuits,global transcription machinery engineering(gTME)and bioprocess integration.Furthermore,by integrating the advantages of these strategies and reducing the cost of system operation,the tolerance of industrial strains,combined with production efficiency and process stability,will be greatly improved,and the development prospects of biorefinery will be more widespread.

Environmental Stresses Modulate Abundance and Timing of Alternatively Spliced Circadian Transcripts in Arabidopsis

Environmental stresses profoundly altered accumulation of nonsense mRNAs including intron-retaining （IR） transcripts in Arabidopsis. Temporal patterns of stress-induced IR mRNAs were dissected using both oscillating and non-oscillating transcripts. Broad-range thermal cycles triggered a sharp increase in the long IR CCA1 isoforms and altered their phasing to different times of day. Both abiotic and biotic stresses such as drought or Pseudomonas syringae infection induced a similar increase. Thermal stress induced a time delay in accumulation of CCA1 14Rb transcripts, whereas functional mRNA showed steady oscillations. Our data favor a hypothesis that stress-induced instabilities of the central oscillator can be in part compensated through fluctuations in abundance and out-of-phase oscillations of CCA1 IR transcripts. Taken together, our results support a concept that mRNA abundance can be modulated through altering ratios between functional and nonsense/IR transcripts. SR45 protein specifically bound to the retained CCA1 intron in vitro, suggesting that this sp!icing factor could be involved in regulation of intron retention. Transcriptomes of nonsense-mediated mRNA decay （NMD）-impaired and heat-stressed plants shared a set of retained introns associated with stress- and defense-inducible transcripts. Constitutive activation of certain stress response networks in an NMD mutant could be linked to disequilibrium between functional and nonsense mRNAs.

Lipidomics in archaeal membrane adaptation to environmental stresses and growth conditions:A review of culture-based physiological studies

Membrane lipids are thought to be a crucial part of the homeoviscous adaptation of archaea to extreme conditions.This article reviews the recent lipidomic studies of physiological membrane adaptations of archaea,assesses the biomolecular basis of an organic paleothermometer,TEX86,and contemplates the future directions of archaeal lipidomics.The studies of extremophilic archaea have revealed that at least three different molecular mechanisms are involved in membrane adaptation of archaea:(1)regulation of the number of cyclopentane rings of caldarchaeol,(2)alteration of the diether-to-tetraether lipid ratio,and(3)variation of the proportion of saturated and unsaturated lipids.However,most of the studies have focused on a limited number of archaeal ether-linked lipids,such as glycerol dialkyl glycerol tetraethers(GDGTs),which only represent a fraction of the entire lipidome.Environmental factors such as growth temperature and pH have been most frequently reported,but biotic factors,including growth phases,nutrition,and enzymatic activities affecting the membrane lipid composition are often overlooked.Membrane lipids of mesophilic ammonia-oxidizing marine Thaumarchaeota have been applied in the reconstruction of past sea surface temperatures.However,recent culture-based physiological studies have demonstrated that non-thermal biotic factors,including dissolved oxygen,ammonia oxidation rate and the growth rate,are the main drivers of GDGT cyclization in Nitrosopumilus maritimus.Moreover,other related strains or ecotypes exhibit a markedly different set of stress adaptations.A trend is now developing to examine the whole lipid profile(lipidome)for studies of archaeal physiology and biochemistry related to lipid biosynthesis(lipidomics)to gain a better understanding of the biological mechanisms underpinning the applications of membrane lipid-based proxies in biogeochemical or ecological research.

Identification of Light-Harvesting Chlorophyll a/b-Binding Protein Genes of Zostera marina L.and Their Expression Under Different Environmental Conditions

Photosynthesis includes the collection of light and a/b-binding （LHC） proteins. In high plants, the LHC gene family constituting the light-harvesting complex ofphotosystems I and II. the transfer of solar energy using light-harvesting chlorophyll includes LHCA and LHCB sub-families, which encode proteins Zostera marina L. is a monocotyledonous angiosperm and inhab- its submerged marine environments rather than land environments. We characterized the Lhca and Lhcb gene families of Z. marina from the expressed sequence tags （EST） database. In total, 13 unigenes were annotated as ZmLhc, 6 in Lhca family and 7 in ZmLhcb family. ZmLHCA and ZmLHCB contained the conservative LHC motifs and amino acid residues binding chlorophyll. The average similarity among mature ZmLHCA and ZmLHCB was 48.91% and 48.66%, respectively, which indicated a high degree of diver- gence within ZmLHChc gene family. The reconstructed phylogenetic tree showed that the tree topology and phylogenetic relation- ship were similar to those reported in other high plants, suggesting that the Lhc genes were highly conservative and the classification of ZmLhc genes was consistent with the evolutionary position of Z. marina. Real-time reverse transcription （RT） PCR analysis showed that different members of ZmLhca and ZmLhcb responded to a stress in different expression patterns. Salinity, temperature, light intensity and light quality may affect the expression of most ZmLhca and ZmLhcb genes. Inorganic carbon concentration and acidity had no obvious effect on ZmLhca and ZmLhcb gene expression, except for ZmLhca6.

Genetic Diversity Caused by Environmental Stress in Natural Populations of Niupidujuan as Revealed by RAPD Technique

Multiplex environmental factors are generally expected to have significant effects on genetic diversity of plant populations.In this study,randomly amplified polymorphic DNA（RAPD） technique was used to reveal the genetic diversity in the same species of four populations collected from Niupidujuan（Rhododendron chrysanthum） at different altitudes,an endangered species,endemic to Northeast China.Initially,twenty informative and reproducible primers were chosen for final RAPD analysis.A total of 152 clear bands were obtained,including 143 polymorphic ones.With the help of POPGENE software,the poly rate was calculated to be 94.07% and the evenness of amplified bands for every primer was 6.8.Additionally,the mean observed number of alleles was 1.7265 with an effective number of 1.3608.An examination of the gene indicated a diversity of 0.2162 with an information diversity index of 0.3313.For these data,the clustering blurred analysis was performed with the aid of NTSYS-pc software to define the Nei＇s gene diversity and the Shannon information diversity index of the four plant populations.The relationships between the genetic diversity indexes on the one hand and the geographic and climatic factors on the other hand were estimated by the Pearson correlation with SPSS 11.0 software.The results of the correlation analysis show that there were significant（P〈0.05） or highly significant（P〈0.01） correlations between each of the genetic diversity indexes and the different temperature which were mainly caused by the altitude different populations located.These data highlight the importance of native populations in shaping the spatial genetic structure in Niupidujuan.

Temporal dynamics of phytoplankton communities in a semi-enclosed mariculture pond and their responses to environmental factors

Variations in physical-chemical factors, species composition, abundance and biomass of nano-and micro-phytoplankton assemblages, as well as their responses to environmental factors, were investigated over a complete cycle (6 months) in a semi-enclosed shrimp-farming pond near Qingdao, northern China. The aim was to establish the temporal patterns of phytoplankton communities and to evaluate protists as suitable bioindicators to water quality in mariculture systems. A total of 34 taxa with nine dominant species were identified, belonging to six taxonomic groups (dinoflagellates, diatoms, cryptophyceans, chlorophyceans, euglenophyceans and chrysophyceans). A single peak of protist abundance occurred in October, mainly due to chlorophyceans, diatoms and chrysophyceans. Two biomass peaks in July and October were primarily due to dinoflagellates and diatoms. Temporal patterns of the phytoplankton communities significantly correlated with the changes in nutrients, temperature and pH, especially phosphate, either alone or in combination with NO3-N and NH3-N. Species diversity, evenness and richness indices were clearly correlated with water temperature and/or salinity, whereas the biomass/abundance ratio showed a significant correlation with NO3-N. The results suggest that phytoplankton are potentially useful bioindicators to water quality in semi-enclosed mariculture systems.

Planktonic protist communities in semi-enclosed mariculture waters: temporal dynamics of functional groups and their responses to environmental conditions

The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period （a complete shrimp-culture cycle） from May to October 2002.The results reveal that： （1） the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;（2） the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample （early June）;（3） the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;（4） five functional groups of protist communities represented significant correlations with water nutrients （i.e.,NH 3-N,NO 3-N,and PO 4 ）,either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.

Temporal species distributions of planktonic protist communities in semi-enclosed mariculture waters and responses to environmental stress

In order to evaluate the relationships between temporal species succession of planktonic protists and physical-chemical parameters in semi-enclosed mariculture waters, species distributions in response to environmental stress were investigated in a shrimp-farming pond near Qingdao, China during a complete shrimp-culture cycle （May to October 2002）. A clear temporal succession in species distribution was found over the complete farming cycle. For example, before the introduction of the shrimp larvae there was low-variability of species distribution in the protist communities whereas during the stages immediately after, there was higher variability in species composition. Multiple linear/logistic regression analyses demonstrate that 12 protist taxa （e.g., Gyrodinium spirale, Teleaulax acuta, Prorocentrum spp. and Mesodinium pupula） were related to the nutrients, in particular ammonia and phosphates, alone or in combination with water temperature. These results suggest that temporal variations in species distribution of planktonic protist communities might be used in assessing water quality of semi-enclosed mariculture waters.

Sap flow response of Eucaylyptus (Eucalyptus urophylla) to environmental stress in South China

Sap flow and environmental conditions were monitored at two Eucalyptus (Eucalyptus urophylla S.T.Blake) plantations at Hetou and Jijia, located in Leizhou, Zhanjiang, Guangdong Province. It was found that daily sap flux density (SFD) of Eucalyptus was closely related to daily atmospheric vapor pressure deficit (VPD) (R2=0.76, P=0.01 at Hetou and R2=0.7021, P=0.01 at Jijia) at both sites. No significant relationship existed between daily SFD and mean daily air temperature at both sites. Daily SFD varied with wind speed Y=-17585X3+15147X2-1250.7X+2278.4 (R2=0.68; P=0.01) at Hetou and Y=-101.67X3-1.65X2-376.4X+1914.8 (R2=0.40,P=0.05) at Jijia, where Y was daily SFD,X was daily wind speed. Experimental observations yielded the following data: (1) the critical lower and upper daily VPD threshold were 0 and 2 kPa, within which daily SFD varied from 540±70 L/(m2·d) to 4739±115 L/(m2·d) at Hetou site, from 397±26 L/(m2·d) to 3414±191 L/(m2·d) at Jijia site; (2) Diurnal SFDs at Hetou site were much higher under low relative humidity (<30%) and slightly lower under high relative humidity (>%) compared with those at the Jijia site; (3) The upper and lower threshold of daily and diurnal RAD for the optimal water use of E. urophylla plantations were 18±2.7 and 2±1 MJ/(m2·d), 669 and 0 J/(cm2·h) during the observation period.

Contributions of aversive environmental stress to migraine chronification:Research update of migraine pathophysiology

Clinical studies have suggested that internal and/or external aversive cues may produce a negative affective-motivational component whereby maladaptive responses(plasticity)of dural afferent neurons are initiated contributing to migraine chronification.However,pathophysiological processes and neural circuitry involved in aversion(unpleasantness)-producing migraine chronification are still evolving.An interdisciplinary team conducted this narrative review aimed at reviewing neuronal plasticity for developing migraine chronicity and its relevant neurocircuits and providing the most cutting-edge information on neuronal mechanisms involved in the processing of affective aspects of pain and the role of unpleasantness evoked by internal and/or external cues in facilitating the chronification process of migraine headache.Thus,information presented in this review promotes the understanding of the pathophysiology of chronic migraine and contribution of unpleasantness(aversion)to migraine chronification.We hope that it will bring clinicians’attention to how the maladaptive neuroplasticity of the emotion brain in the aversive environment produces a significant impact on the chronification of migraine headache,which will in turn lead to new therapeutic strategies for this type of pain.

Research Progress on Lonicera japonica Thunb.Affected by Environmental Stress

Lonicera japonica Thunb.is widely distributed in China.It has strong adaptability to the environment and can maintain normal growth and development under a variety of stress conditions.It is commonly used as a medicine with its dry flower buds or newly opened flowers,named honeysuckle,and with both economic value and ecological application value.The research progress of L.japonica Thunb.under stress conditions such as temperature,drought,light,salt,heavy metals and diseases,pests and endophytic bacteria was reviewed,and the current research situation of the physiological and biochemical response mechanism,changes of photosynthetic fluorescence and accumulation of secondary metabolites of honeysuckle under different stresses was discussed,so as to provide a reference for deep-level exploring the resistance mechanism of L.japonica Thunb.in the future and lay a theoretical foundation for the high-quality authentic ecological cultivation of L.japonica Thunb.

The Role of Environmental Stress in Determining Gut Microbiome:Case Study of Two Sympatric Toad-headed Lizards

The gut microbiota has gained attention because of its importance in facilitating host survival and evolution.However,it is unclear whether gut microbial communities are determined by the host(heritable factor) or environment(environmental factor).In this study,we investigated the gut microbial communities and potential functional signatures of two sympatric species distributed along an elevation gradient,the toadheaded lizards Phrynocephalus axillaris and P.forsythii.Our results indicated that at high elevations,the gut microbial communities of P.axillaris and P.forsythii did not significantly differ,and the phylogenetic relationships of gut microbial communities contradicted their hosts.At low altitudes,the two lizards could be distinguished based on their significantly different gut microbial communities.Compared to low-altitude populations,Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis showed that at higher altitudes,energy metabolism,such as carbohydrate,lipid,and amino acids metabolism were higher in both lizards.While a larger number of pathogenic bacteria were found in the lowaltitude population of P.forsythii.This suggests that the convergence of gut microbiota of two lizards at highaltitude stem from environmental factors,as they were exposed to the same environmental stress,whereas the divergence at low-altitude stemmed from heritable factors,as they were exposed to different environmental stresses.These results provide a new perspective regarding whether heritable or environmental factors dominate the gut microbiota during exposure to environmental stress.

Observation of Cell-Size Variation under Environmental Stress by Fluorescence Correlation Spectroscopy without Objective Image Magnification

Fluorescence correlation spectroscopy （FCS） without objective image magnification （without using con-focal microscope） was applied to observe the variation in cell size of Escherichia coli （E. coli） induced by the anti-cancer agent MitomycinC （MMC）. In the system without image magnification followed in this study, the suspension of E. coli cells was stirred, and the difference in movement due to the different cell sizes induced by the compulsive solution flow was detected. The addition of 0.1-0.4 pg/L of MMC elongated the E. coli cell length from about 3.6 to 7.8μm. The flow cell （i.d. = about 1 mm） also produced a size-dependent correlation curve, The present system is not based on single molecular FCS but is inexpensive and effective at observing the variation in cell size induced by environmental changes.

Seedling’s Vigor of Tomato and Paprika Genotypes under a Simulated Model of Multiple Abiotic Stresses and Lower Dosage of Salicylic Acid (C7H6O3)

Seedling vigor in tomato and paprika is affected by variety. Genotype selection under environmental stresses and its effects on seedling vigor was investigated. During the year 2021, the study was carried out and it revealed an appropriate selection for open field gardeners. The selection of two drought-tolerant, and one non-drought tolerant cultivars was the initial stage. Six commercial genotypes were evaluated (three for tomato and three for paprika). The second phase involved planting cultivars till the cotyledon leaves phase, and the first set of true leaves. Seedlings were investigated under simulated environmental stresses of non-ideal temperatures, low humidity, closed spacing, minimum light dose, nutrient-deficient water, and spraying a lower dosage of salicylic acid. The evaluation of seedling’s growth was performed by measuring germination percentage, seedling length, shoot length, root length, seedling fresh weight, seedling dry weight, and seedling vigor index. Tomato (Mobil) and paprika (Carma) seedlings outperform other varieties, possibly because of the variety’s vigor under various stress conditions. These findings reveal that tomato (Mobil) and paprika (Carma) had a positive impact on development and may be raised under optimal conditions of nurseries and then be transferred to open-air environmental and biological exposed conditions in Hungary.

Body color plasticity of Diaphorina citri reflects a response to environmental stress

Body color polyphenism is common in Diaphorina citri.Previous studies compared physiological characteristics in D.citri,but the ecological and biological significance of its body color polyphenism remains poorly understood.We studied the ecological and molecular effects of stressors related to body color in D.citri.Crowding or low temperature induced a high proportion of gray morphs,which had smaller bodies,lower body weight,and greater susceptibility to the insecticide dinotefuran.We performed transcriptomic and metabolomics analysis of 2 color morphs in D.citri.Gene expression dynamics revealed that the differentially expressed genes were predominantly involved in energy metabolism,including fatty acid metabolism,amino acid metabolism,and carbohydrate metabolism.Among these genes,plexin,glycosidase,phospholipase,take out,trypsin,and triacylglycerol lipase were differentially expressed in 2 color morphs,and 6 hsps(3 hsp70,hsp83,hsp90,hsp68)were upregulated in gray morphs.The metabolome data showed that blue morphs exhibited a higher abundance of fatty acid and amino acid,whereas the content of carbohydrates was elevated in gray morphs.This study partly explains the body color polyphenism of D.citri and provides insights into the molecular changes of stress response of D.citri.

Context‑dependent antioxidant defense system(ADS)‑based stress memory in response to recurrent environmental challenges in congeneric invasive species

Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.

Research advances on the biological effects of elevated ultraviolet-B radiation on terrestrial plants

This review describes the effects of ultraviolet-B （UV-B） radiation on plant growth and development, photosynthesis and photosynthetic pigments and UV-B absorbing compounds. Moreover, plant ecosystem level responses to elevated UV-B radiation and interactions of UV-B radiation with abiotic and biotic factors were also involved. Results collected in this review suggest that approximately two-thirds terrestrial plant species are significantly affected by increase in UV-B radiation, The majority of evidences indicate that elevated UV-B radiation is usually detrimental but there exists tremendous variability in the sensitivity of species to UV-B radiation, and sensitivity also differs among cultivars of the same species.

Advances in the Regulation of RpoS Protein Expression and Its Function in Bacteria

RpoS protein is a σ factor of RNA polymerase that can control the expression of a group-specific gene, thus playing a vital role in bacteria. In bacteria, RpoS expression is under strict control and is mainly regulated at three levels： transcription level, translation level and post-translational level. Environmental stress enters bacterial cells through signal transduction and leads to a series of variations in microenvironment, thereby causing changes of regulator and controlling its levels based on the direct and indirect interaction between regulator and RpoS protein. In addition, RpoS protein has played special roles in bacteria, therefore the changes of RpoS protein levels will lead to variations in expression levels of a large number of genes, thereby causing variations of bacterial response to different environmental stress and changes of certain characteristics of bacteria, which provides a new strategy for the control of bacterial diseases in the future. This paper reviewed the recent progress on the regulation of RpoS protein expression and its function in several common bacteria. Due to the functional complexity of RpoS protein, there are still a lot of unknown functions to be further identified.