The effects of climatic warming on phyllosphere microbial communities remain uncertain.  In this study, the effects of long-term (>10 years) experimental warming on phyllosphere epiphytic bacterial and fungal communities of Carex alrofusca, Kobresia pygmaea, Potentilla bifurca and Stipa capillacea were examined in the northern Tibet.  Overall, warming increased bacterial α-diversity, but reduced fungal α-diversity across the four host plants.  Warming altered the bacterial and fungal community compositions mainly by increasing Actinobacteria, Firmicutes and pathotroph-saprotroph fungi, and reducing Basidiomycota and symbiotroph fungi across the four host plants.  Warming increased the relative effect of the ‘drift & others’ process in the bacterial community, but reduced the relative effect of the ‘dispersal limitation’ process in the bacterial community and the relative effect of the ‘homogeneous selection’ process in the fungal community across the four host plants.  The overall warming effects on the bacterial and fungal communities may be due to overall warming effects on temperature, leaf morphology structure and physicochemical properties, ecological processes of community assembly and topological parameters of species co-occurrence networks of bacteria and fungi.  Warming altered the bacterial species co-occurrence network mainly by increasing the vertex, clustering coefficient and heterogeneity, while reducing the average path length and network diameter across host species.  Warming altered the fungal species co-occurrence network mainly by increasing the network diameter and reducing the vertex across host species.  Warming effects on bacterial and fungal communities varied among host plants, which may be due to the diverse responses to warming of plant height, leaf malondialdehyde, ecological processes of community assembly and topological parameters of species co-occurrence network.  Therefore, warming can alter phyllosphere epiphytic bacterial and fungal communities of alpine plants.  Such changes varied among host plants and may cause adverse effects on the host plants.

Nitrogen (N) enrichment is expected to induce a greater phosphorus (P) limitation, despite the acceleration of soil P cycling.  However, the changing patterns in plant P and soil available P after N enrichment, and their regulatory mechanisms, remain poorly understood in alpine meadows.  Here, we conducted a field experiment with four N addition rates (0, 5, 10, and 15 g N m^–2 yr^–1) in an alpine meadow, and investigated the P in plants, microorganisms, and soil to determine their patterns of change after short-term N addition.  Our results showed that N addition significantly increased plant biomass, and the plant P pool showed a non-linear response to the N addition gradient.  Soil available P initially increased and then declined with increasing N addition, whereas the occluded inorganic P decreased markedly.  The critical factors for soil available P varied with different N addition rates.  At lower N addition levels (0 and 5 g N m^–2 yr^–1), soil acidification facilitated the mobilization of occluded inorganic P to increase soil available P.  Conversely, at higher N addition levels (10 and 15 g N m^–2 yr^–1), the elevated soil microbial biomass P intensified the competition with plants for soil P, leading to a decline in soil available P.  This study highlights the non-linear responses of the plant P pool and soil available P concentration to N addition rates.  These responses suggest the need for developing ecosystem models to assess different effects of increasing N rates, which would enable more accurate predictions of the plant P supply and soil P cycling under N enrichment.

The agro-pastoral ecotone epitomizes the ecologically fragile semi-arid zone, where the soil microbiomes play a pivotal role in regulating its multifunctionality.  However, whether and how changes in soil structure and organic matter composition under different land uses affect microbial community structure remain unclear.  Here, land-use types in the agro-pastoral ecotone, including shrubland (BF), artificial grassland (ArG), abandoned grassland (AbG), and maize farmland (MA), were chosen to explore the response relationships between soil microbial communities and the aggregates and dissolved organic matter (DOM) composition.  The results showed that compared to MA, the macroaggregates in BF, AbG, and ArG were increased by 123.0, 92.79, and 63.71%, respectively, while MA soil had the greatest abundance of <100 μm particles.  The higher aromatic carbon with high aromaticity and molecular weight in BF soil DOM contributed to its highest mineral-associated organic carbon level (12.61 g kg^–1), while MA soil organic carbon had highly efficient decomposition due to its high content of aliphatic and carboxy carbon, so it is prone to loss from the active carbon pools.  The transition in land use from shrubland to grassland and farmland has facilitated the conversion of stable aromatic carbon to unstable carboxy carbon.  The taxonomic analysis revealed that soil bacterial and fungal communities in the four land uses were dominated by Proteobacteria, Actinobacteriota, Chloroflexi, and Ascomycota.  More taxonomic groups from phylum to family were enriched in BF soil.  The DOM components and organic carbon are crucial variables shaping the composition of soil bacterial communities, jointly explaining 61.66% of the variance, while aggregates are important variables driving the composition of fungal communities, with an explanation rate of 20.49%.  Our results suggest that DOM components and aggregates impact the soil microbial structure; and the transition in land use from agricultural land to grassland and shrubland in the agro-pastoral ecotone enhances aggregate stability, carbon sequestration potential, and microbial diversity.

Tibetan alpine steppes are large and sensitive terrestrial carbon (C) reservoirs that are experiencing desertification due to global change and overgrazing, which can lead to stronger resource limitations for both above- and below-ground communities. Soil nutrients, especially nitrogen (N) and phosphorus (P), are the crucial resources for plant growth and microbial metabolism. However, whether both plant and soil microbial communities in the degraded alpine steppes are limited by these soil nutrients remains unclear, which limits our understanding of the mechanisms of desertification and subsequent ecosystem restoration. Here, we evaluated potential nutrient limitations of the plant and soil microbial communities in the alpine steppe across five stages of desertification using stoichiometry-based approaches. Our results showed that soil microbial metabolism was mainly limited by C and P, and the plant N limitation and microbial C limitation were intensified while the microbial P limitation was relieved during desertification. Plant-soil-microbe interactions had significant impacts on the microbial C and P limitations, explaining 72 and 61% of the variation, respectively. Specifically, desertification ultimately affected microbial metabolic limitations by regulating soil pH, soil nutrients, and the plant N limitation. Moreover, the microbial C limitation further reduced microbial C use efficiency (CUE) with desertification, which is detrimental for organic C retention in the degraded soil. Overall, this study revealed that microbial metabolic limitations through plant-microbe interactions were the key drivers affecting soil microbial CUE, and it provided insights that can advance our knowledge of the microbial regulation of nutrient cycles and C sequestration.

Plant community composition typically undergoes progressive changes along environmental gradients.  However, most experimental studies have focused on individual communities, so it remains unclear how exogenous nutrient inputs affect the stability of plant communities along environmental gradients.  Along a rainfall gradient on the northern Tibetan Plateau, we conducted an 8-year nitrogen (N) addition experiment in four alpine grasslands: alpine desert steppe (ADS), alpine steppe (AS), alpine meadow steppe (AMS), alpine meadow (AM), and we used two-way ANOVA to examine the effects of N addition on the temporal stability of these different alpine grasslands.  We found that community aboveground biomass showed saturation trends in AM and AMS with increasing N gradients, while there was no change in AS and a gradual increase in ADS.  The temporal stability showed different patterns of gradual decreases in ADS and AM, and a unimodal trend in AMS with increasing N gradients.  However, N addition had no effect on the temporal stability of AS.  Dominant species stability was the controlling factor for alpine grasslands along the transect, while the effect of asynchrony gradually increased with decreasing precipitation.  These findings highlight that community composition, especially the dominant species, along the environmental gradient can mediate the effects of N inputs on community temporal stability.  Thus, the conservation and restoration of the dominant species are particularly important under future scenarios of increased atmospheric N deposition.

Plant roots interact with diverse fungi that are essential for maintaining the productivity and sustainability of pasture ecosystems, but how these root-associated fungi (RAF) differ between forage species and how they respond to nutrient enrichment and fungicide application are not well understood.  Here, we constructed an 11-year experiment involving fungicide application (with or without) nested within four levels of experimental nitrogen (N) addition treatments in an alpine pasture, and the RAF communities, root traits, tissue nutrients, and shoot biomass of two dominant forage species (Carex capillifolia and Elymus nutans) were analyzed.  The RAF community composition showed striking differences between the plant species and was strongly affected by both N addition level and fungicide applications.  Fungicide, but not N application, dramatically reduced the RAF richness of all functional guilds in both plant species, and fungicide also simplified the co-occurrence network of the RAF for C. capillifolia.  The RAF community correlated strongly with root traits, whereas their relationships became weakened or even vanished at the level of the individual plant species.  The importance of RAF to plant nutrients and productivity varied between plant species, with significant contributions in C. capillifolia but not in E. nutans.  This is the first report elucidating the long-term effect of fungicides on RAF in alpine pastures, and our findings emphasize the host-specific responses of RAF community structure and function to anthropogenic disturbances.

The response of N₂O emissions to nitrogen (N) addition is usually positive, but its response to phosphorus (P) addition varies, and the underlying mechanisms for the changes in N₂O emissions remain unclear.  We conducted field studies to examine the response of N₂O emissions to N and P addition over two years in three typical alpine grasslands, alpine meadow (AM), alpine steppe (AS), and alpine cultivated grassland (CG) on the Qinghai-Tibet Plateau (QTP).  Our results showed consistent increases in N₂O emissions under N addition alone or with P addition, and insignificant change in N₂O emissions under P addition alone in all three grasslands.  N addition increased N₂O emissions directly in AM, by lowering soil pH in AS, and by lowering abundance of denitrification genes in CG.  N and P co-addition increased N₂O emissions in AM and AS but only showed an interactive effect in AM.  P addition enhanced the increase in N₂O emissions caused by N addition mainly by promoting plant growth in AM.  Overall, our results illustrate that short-term P addition cannot alleviate the stimulation of N₂O emissions by N deposition in alpine grassland ecosystems, and may even further stimulate N₂O emissions.

Fencing for grazing exclusion is regarded as a traditional and effective method for the natural restoration of degraded alpine steppe, and it effectively promotes plant growth and enhances soil carbon stocks.  Arbuscular mycorrhizal fungi (AMF) are essential microorganisms in grassland that play a major role in plant-derived C translocation into the soil.  However, the effects of fencing on AMF communities and their contributions to soil carbon sequestration are still unclear.  In this study, alpine steppe areas with three different fencing durations (free grazing, medium-term fencing for 5–6 years and long-term fencing for more than 10 years) in the northern Tibetan Plateau were selected to explore the effects of grazing exclusion on AMF communities and their roles in soil carbon sequestration.  The results showed that medium- and long-term fencing significantly increased both plant aboveground biomass and soil organic carbon (SOC) content.  The AMF community composition varied significantly during different fencing durations, with a dramatic increase in the relative abundance of Glomus but a significant reduction in the relative abundance of Diversispora with longer fencing time.  Medium-term fencing significantly increased AMF richness and the Shannon-Wiener index.  Meanwhile, fencing significantly increased hyphal length density (HLD), glomalin-related soil protein (GRSP) and the proportion of macroaggregates (250–2,000 μm), all of which contribute positively to SOC.  Structural equation modeling revealed that fencing time positively influenced HLD and the AMF community composition, subsequently affecting T-GRSP, which was tightly correlated with SOC.  Our findings suggest the potentially important contribution of AMF to SOC sequestration, so more attention should be paid to AMF during alpine steppe fencing, particularly for enhancing the efficiency of degraded grassland restoration efforts.

The response of plant functional diversity to external disturbances not only effectively predicts changes in the ecosystem but it also reflects how plant communities use external environmental resources.  However, research on how different herbivore assemblages affect plant functional diversity is limited.  Therefore, this study systematically explored the effects of three typical herbivore assemblages (yak grazing, Tibetan sheep grazing, and mixed grazing by yaks and Tibetan sheep) on species richness, plant functional diversity, and soil physicochemical properties in alpine grasslands on the Qinghai-Tibet Plateau, China.  This study further investigated the primary mechanisms driving the changes in plant functional diversity.  The results indicate four key aspects of this system: (1) Grazing significantly enhanced plant functional diversity, particularly when the mixed grazing by yaks and Tibetan sheep was applied at a ratio of 1:2.  This ratio showed the most substantial improvement in the functional dispersion index and Rao’s quadratic entropy index.  (2) Compared to enclosed treatments, grazing increased species richness and β-diversity, contributing to higher plant functional diversity.  (3) Grazing treatments affected various plant traits, such as reducing plant community height and leaf thickness while increasing specific leaf area.  However, the impact on plant functional diversity was most pronounced under the mixed grazing by yaks and Tibetan sheep at a ratio of 1:2.  (4) Species α-diversity was positively correlated with plant functional diversity.  Changes in plant functional diversity were primarily regulated by variations in soil physicochemical properties.  Specifically, increases in soil available nitrogen significantly promoted changes in plant functional diversity, while increases in soil available potassium and bulk density had a significant inhibitory effect on these changes.  Long-term grazing significantly reduced the height of plant communities in alpine meadows, while a balanced mixture of yak and Tibetan sheep grazing, especially at a ratio of 1:2, enhanced plant functional diversity the most.  This suggests that, under these conditions, the use of external environmental resources by the plant community is optimized.

Grassland degradation presents overwhelming challenges to biodiversity, ecosystem services, and the socio-economic sustainability of dependent communities.  However, a comprehensive synthesis of global knowledge on the frontiers and key areas of grassland degradation research has not been achieved due to the limitations of traditional scientometrics methods.  The present synthesis of information employed BERTopic, an advanced natural language processing tool, to analyze the extensive ecological literature on grassland degradation.  We compiled a dataset of 4,504 publications from the Web of Science core collection database and used it to evaluate the geographic distribution and temporal evolution of different grassland types and available knowledge on the subject.  Our analysis identified key topics in the global grassland degradation research domain, including the effects of grassland degradation on ecosystem functions, grassland ecological restoration and biodiversity conservation, erosion processes and hydrological models in grasslands, and others.  The BERTopic analysis significantly outperforms traditional methods in identifying complex and evolving topics in large datasets of literature.  Compared to traditional scientometrics analysis, BERTopic provides a more comprehensive perspective on the research areas, revealing not only popular topics but also emerging research areas that traditional methods may overlook, although scientometrics offers more specificity and detail.  Therefore, we argue for the simultaneous use of both approaches to achieve more systematic and comprehensive assessments of specific research areas.  This study represents an emerging application of BERTopic algorithms in ecological research, particularly in the critical research focused on global grassland degradation.  It also highlights the need for integrating advanced computational methods in ecological research in this era of data explosion.  Tools like the BERTopic algorithm are essential for enhancing our understanding of complex environmental problems, and it marks an important stride towards more sophisticated, data-driven analysis in ecology.

There is growing interest in introducing ecological risks (ERs) and ecosystem services (ESs) into environmental policies and practices. However, the integration of ESs and ERs into actual decision-making remains insufficient. We simulated the spatiotemporal dynamics of ESs (e.g., carbon storage, water yield, habitat quality, and soil conservation) and ERs in the upper reach of the Yellow River (URYR) from 2000 to 2100. Additionally, we explored their relationships by combining the InVEST model and a landscape ecological risk model with CMIP6 data. Our main findings showed that regional ERs change in response to land use and environmental dynamics. Specifically, the ER area decreased by 27,673 m² during 2000-2020, but it is projected to increase by 13,273, 438, and 68 m² under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. We also observed remarkable spatial differences in ESs and ERs between past and future scenarios. For instance, the source area of the URYR exhibited high ESs and low ERs (P<0.001), while the ESs and ERs are declining and increasing, respectively, in the northeastern URYR (P<0.05). Finally, we proposed a spatial optimization framework to improve ESs and reduce ERs, which will support regional sustainable development.

In the process of feeding, broilers are susceptible to leg diseases, which are often caused by factors such as genetics, bacteria, viruses, the growth environment, and diet management.  Treating leg disorders/diseases in broilers is challenging, and once they suffer from such conditions, it generally leads to reduced production performance and affects the quality of meat.  It is worth mentioning that with the advancement of intensive management technologies and the accelerated growth rate of broilers, the leg diseases in broilers has increased, resulting in higher culling rates during production.  Leg diseases not only cause significant economic losses to the poultry industry, but also severely jeopardize the animal welfare of broilers.  Therefore, effective early diagnosis is crucial to mitigate the adverse effects of chicken leg diseases.  This study aims to review various diagnostic methods, including clinical diagnosis, autopsy, radiological diagnosis, infrared thermal imagery, biomarkers and emerging diagnostic techniques, to establish a theoretical foundation for the identification or monitoring of leg diseases in poultry industry.

Oryza longistaminata is an African wild rice species with valuable agronomic traits and the donor parent of perennial rice.  Endophytic bacteria play an important role in host health, adaptive evolution and stress tolerance.  However, endophytic bacterial communities in O. longistaminata and their plant growth-promoting (PGP) effects on the perennial rice of O. longistaminata offspring are poorly understood.  In this study, the endophytic bacterial diversity, composition and network structures in the root, stem, and leaf tissues of O. longistaminata were characterized using Illumina sequencing of the 16S rRNA gene.  The results suggested that O. longistaminata contains a multitude of niches for different endophytic bacteria, among which the root endosphere is more complex and functionally diverse than the stem and leaf endospheres.  Tissue-specific biomarkers were identified, including Paludibaculum, Pseudactinotalea and Roseimarinus and others, for roots, Blautia for stems and Lachnospiraceae NK4A136 for leaves.  The endophytic bacterial network of O. longistaminata was reassembled for various functions, including degradation/utilization/assimilation, detoxification, generation of precursor metabolites and energy, glycan pathways, macromolecule modification and metabolism.  A total of 163 endophytic bacterial strains with PGP traits of potassium release, phosphate solubilization, nitrogen fixation, siderophore activity, indole-3-acetic acid (IAA) production, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity were isolated from O. longistaminata.  Eleven strains identified as Enterobacter cloacae, Enterobacter ludwigii, Stenotrophomonas maltophilia, Serratia fonticola, and Bacillus velezensis showed stable colonization abilities and PGP effects on perennial rice seedlings.  Inoculated plants generally exhibited an enhanced root system and greater photosynthesis, biomass accumulation and nutrient uptake.  Interestingly, two strains of E. cloacae have host genotype-dependent effects on perennial rice growth.  The results of this study provide insights into the endophytic bacterial ecosystems of O. longistaminata, which can potentially be used as biofertilizers for sustainable perennial rice productivity.

Global warming is primarily characterized by asymmetric temperature increases, with greater temperature rises in winter/spring and at night compared to summer/autumn and the daytime.  We investigated the impact of winter night warming on the top expanded leaves of the spring wheat cultivar Yangmai 18 and the semi-winter wheat cultivar Yannong 19 during the 2020–2021 growing season.  Results showed that the night-time mean temperature in the treatment group was 1.27°C higher than the ambient temperature, and winter night warming increased the yields of both wheat cultivars, the activities of sucrose synthase and sucrose phosphate synthase after anthesis, and the biosynthesis of sucrose and soluble sugars.  Differentially expressed genes (DEGs) were identified using criteria of P-value<0.05 and fold change>2, and they were subjected to Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses.  Genes differentially expressed in wheat leaves treated with night warming were primarily associated with starch and sucrose metabolism, amino acid biosynthesis, carbon metabolism, plant hormone signal transduction, and amino sugar and nucleotide sugar metabolism.  Comparisons between the groups identified 14 DEGs related to temperature.  These results highlight the effects of winter night warming on wheat development from various perspectives.  Our results provide new insights into the molecular mechanisms of the response of wheat to winter night warming and the candidate genes involved in this process.

Photosynthesis is the basis of crop growth and is sensitive to stress.  Smut (Sporisorium destruens) is the primary disease in the production of broomcorn millet (Panicum miliaceum L.).  This study evaluated the effects of infection with S. destruens on the photosynthesis of the resistant cultivar (BM) and susceptible cultivar (NF).  After inoculation, there was a decrease in the chlorophyll content, gas exchange parameters, and chlorophyll fluorescence of the two cultivars.  Observation of the ultrastructure of diseased leaves showed that the chloroplasts and mitochondria had abnormal morphology, and some vacuoles appeared.  RNA-seq was performed on the flag leaves after inoculation.  In addition to the resistant and susceptible cultivars, the diseased leaves developed from inflorescences were defined as S2.  The analysis showed that the pathways related to photosynthesis stimulated some differentially expressed genes (DEGs) after infection with S. destruens.  More DEGs were induced in the susceptible broomcorn millet NF than in the resistant broomcorn millet BM, and most of those genes were downregulated.  The number of DEGs induced by S2 was greater than that in susceptible cultivar NF, and most of them were upregulated.  These results indicate that infection with S. destruens affects the normal photosynthetic performance of broomcorn millet.  Understanding the mechanism between S. destruens, photosynthesis, and broomcorn millet is an effective measure to prevent the occurrence of smut and enhance its resistance. 

Ogura cytoplasmic male sterility (Ogura CMS) was first identified in wild radish (Raphanus sativus) and resulted in complete pollen abortion.  However, the molecular mechanism of Ogura CMS in Chinese cabbage remains unclear.  A cytological analysis confirmed nuclear degradation during the late uninucleate stage of pollen development, which diminished by the tricellular stage.  Concurrently, tapetal cells exhibited abnormal enlargement and vacuolation starting from the tetrad stage.  Serious developmental defects were observed in the pollen wall.  During early pollen development, genes associated with cytochrome c and programmed cell death (PCD) were upregulated in the Ogura CMS line, while genes involved in pollen wall mitosis were downregulated.  Conversely, at the late stage of pollen development, peroxisome and autophagy-related genes in the Ogura CMS line were upregulated.  The mitochondrial orf138 gene mutation triggered the PCD process in tapetal cells, leading to their abnormal enlargement and the degradation of their contents, eventually resulting in vacuolation at the tricellular stage.  These tapetal defects hindered the provision of adequate sporopollenin and nutrients to the microspores, consequently leading to abnormal pollen wall development and abnormal mitosis in the microspores.  Ultimately, nuclear dispersion commenced during the late uninucleate stage, and autophagy occurred in the late stage of pollen development.  Consequently, the plant could not produce functional pollen, resulting in male sterility in Chinese cabbage.  Studies of Ogura CMS can promote the production and application of male sterile materials and enrich male sterile resources, which is of great significance for hybrid breeding.

The low egg production of goose greatly limits the development of the industry.  China possesses the most abundant goose breeds resources.  In this study, genome resequencing data of swan goose (Anser cygnoides) and domesticated high and low laying goose breeds (Anser cygnoides domestiation) were used to identify key genes related to egg laying ability in geese and verify their functions.  Selective sweep analyses revealed 416 genes that were specifically selected during the domestication process from swan geese to high laying geese.  Furthermore, SNPs and Indels markers were used in GWAS analyses between high and low laying breed geese.  The results showed that RTCB, BPIFC, SYN3, SYNE1, VIP, and ESR1 may be related to the differences in laying ability of geese.  Notably, only ESR1 was identified simultaneously by GWAS and selective sweep analysis.  The genotype of Indel_{chr3:54429172}, located downstream of ESR1, was confirmed to affect the expression of ESR1 in the ovarian stroma and showed significant correlation with body weight at first egg and laying frequency of geese.  CCK-8, EdU, and flow cytometry confirmed that ESR1 can promote the apoptosis of goose pre-hierarchical follicles ganulosa cells (phGCs) and inhibit their proliferation.  Combined with transcriptome data, it was found ESR1 involved in the function of goose phGCs may be related to MAPK and TGF-beta signaling pathways.  Overall, our study used genomic information from different goose breeds to identify an indel located in the downstream of ESR1 associated with goose laying ability.  The main pathways and biological processes of ESR1 involved in the regulation of goose laying ability were identified by cell biology and transcriptomics methods.  These results are helpful to further understand the laying ability characteristics of goose and improve the egg production of geese.