Selective inhibition of BCL-2 is expected to enhance therapeutic vulnerability in luminal estrogen receptor-positive breast cancers. We show here that the BCL-2 dependency of luminal tumor cells is ...nevertheless mitigated by breast cancer-associated fibroblasts (bCAFs) in a manner that defines MCL-1 as another critical therapeutic target. bCAFs favor MCL-1 expression and apoptotic resistance in luminal cancer cells in a IL-6 dependent manner while their own, robust, survival also relies on MCL-1. Studies based on ex vivo cultures of human luminal breast cancer tissues further argue that the contribution of stroma-derived signals to MCL-1 expression shapes BCL-2 dependency. Thus, MCL-1 inhibitors are beneficial for targeted apoptosis of breast tumor ecosystems, even in a subtype where MCL-1 dependency is not intrinsically driven by oncogenic pathways.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The stability of ecological communities is critical for the stable provisioning of ecosystem services, such as food and forage production, carbon sequestration, and soil fertility. Greater ...biodiversity is expected to enhance stability across years by decreasing synchrony among species, but the drivers of stability in nature remain poorly resolved. Our analysis of time series from 79 datasets across the world showed that stability was associated more strongly with the degree of synchrony among dominant species than with species richness. The relatively weak influence of species richness is consistent with theory predicting that the effect of richness on stability weakens when synchrony is higher than expected under random fluctuations, which was the case in most communities. Land management, nutrient addition, and climate change treatments had relatively weak and varying effects on stability, modifying how species richness, synchrony, and stability interact. Our results demonstrate the prevalence of biotic drivers on ecosystem stability, with the potential for environmental drivers to alter the intricate relationship among richness, synchrony, and stability.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
•Most grassland models ignore thermal acclimation of plants.•Acclimation effects are introduced in the Pasture Simulation model (PaSim).•We simulate C fluxes of grasslands with both existing (EMS) ...and modified (MMS) PaSim.•Harvested biomass is better approached by MMS under extreme weather conditions.•Improved C balances with extensive grazing are obtained with MMS.
A modelling approach for the thermal acclimation of plant photosynthesis and respiration is presented that accounts for changes in the maximum carbon (C) assimilation with changing growth temperature. It is motivated by one key observation, i.e. the optimum temperature for plant processes increases with increasing growth temperature, and two corollary expectations: (i) this determines a modification of the response curve of C assimilation, and (ii) plant C release (respiration) is also affected by changing growth temperature. Simple relations are proposed to model these phenomena, consistent with the Farquhar model of photosynthesis. The incorporation of temperature acclimation of plant photosynthesis and respiration into the Farquhar-based scheme of the Pasture Simulation model (PaSim; EMS: existing modelling solution, MMS: modified modelling solution) is proposed as a way to reduce the uncertainty in estimations of harvested or standing above ground biomass and C fluxes from grassland systems in Central France. Here we show that, across a flux tower grassland site spanning two alternative grazing regimes (Laqueuille, 45° 38′ N, 02° 44′ E, 1040m a.s.l.), acclimation parameterizations improve model ability to reproduce observed ecosystem respiration (especially with extensive grazing, where root mean square error RMSE lowered from 15.20 to 11.59gCm−2week−1). An assessment at two grassland systems (Saint-Genès-Champanelle and Theix, 45° 43′ N, 03° 01′ E, 880m a.s.l.) with alternative cutting regimes and climate conditions also showed some improvements in biomass estimates (e.g. with frequent cutting and experimental extreme summer event RMSE changed from 0.86 to 0.40tDMha−1). The consequences of acclimation for simulated grassland outputs depend on the conditions evaluated which requires further studies. However, our results suggest that grassland modelling omitting plant temperature acclimation is likely to overestimate C emissions, thus biasing projections of future C storage and estimates of policy-making indicators.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Ecological theory posits that temporal stability patterns in plant populations are associated with differences in species' ecological strategies. However, empirical evidence is lacking about which ...traits, or trade-offs, underlie species stability, especially across different biomes. We compiled a worldwide collection of long-term permanent vegetation records (greater than 7000 plots from 78 datasets) from a large range of habitats which we combined with existing trait databases. We tested whether the observed inter-annual variability in species abundance (coefficient of variation) was related to multiple individual traits. We found that populations with greater leaf dry matter content and seed mass were more stable over time. Despite the variability explained by these traits being low, their effect was consistent across different datasets. Other traits played a significant, albeit weaker, role in species stability, and the inclusion of multi-variate axes or phylogeny did not substantially modify nor improve predictions. These results provide empirical evidence and highlight the relevance of specific ecological trade-offs, i.e. in different resource-use and dispersal strategies, for plant populations stability across multiple biomes. Further research is, however, necessary to integrate and evaluate the role of other specific traits, often not available in databases, and intraspecific trait variability in modulating species stability.
Enhancement of soil nitrogen (N) cycling by grazing has been observed in many grassland ecosystems. However, whether grazing affects the activity only of the key microbial functional groups driving ...soil N dynamics or also affects the size (cell number) and/or composition of these groups remains largely unknown. We studied the enzyme activity, size, and composition of five soil microbial communities (total microbial and total bacterial communities, and three functional groups driving N dynamics: nitrifiers, denitrifiers, and free N2fixers) in grassland sites experiencing contrasting sheep grazing regimes (one light grazing LG site and one intensive grazing IG site) at two topographical locations. Enzyme activity was determined by potential carbon mineralization, nitrification, denitrification, and N2fixation assays. The size of each community (except N2fixers) was measured by the most-probable-number technique. The composition of the total soil microbial community was characterized by phospholipid fatty acid analysis (PLFA), and the genetic structure of the total bacterial community was assessed by ribosomal intergenic spacer analysis. The genetic structures of the ammonia-oxidizing, nitrate-reducing, and N2-fixing communities were characterized by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) or by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) targeting group-specific genes. Greater enzyme activities, particularly for nitrification, were observed in IG than in LG sites at both topographical locations. The numbers of heterotrophs, nitrifiers, and denitrifiers were higher in IG than in LG sites at both topographical locations. The amplitude of changes in community size was higher than that of community enzyme activity. Phospholipid and nucleic acid analyses showed that the composition/structure of all the communities, except nitrate reducers, differed between IG and LG sites at both locations. For each community, changes in activity were correlated with changes in the occurrence of a few individual PLFAs or DNA fragments. Our results thus indicate that grazing enhances the activity of soil microbial communities but also concurrently induces changes in the size and composition/structure of these communities on the sites studied. Although the generality of our conclusions should be tested in other systems, these results are of major importance for predicting the effects of future disturbances or changed grazing regimes on the functioning of grazed ecosystems.
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BFBNIB, FZAB, GIS, IJS, INZLJ, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZRSKP
Summary
Management by combined grazing and mowing events is commonly used in grasslands, which influences the activity and composition of soil bacterial communities. Whether observed effects are ...mediated by management‐induced disturbances, or indirectly by changes in the identity of major plant species, is still unknown. To address this issue, we quantified substrate‐induced respiration (SIR), and the nitrification, denitrification and free‐living N2‐fixation enzyme activities below grass tufts of three major plant species (Holcus lanatus, Arrhenatherum elatius and Dactylis glomerata) in extensively or intensively managed grasslands. The genetic structures of eubacterial, ammonia oxidizing, nitrate reducing, and free‐living N2‐fixing communities were also characterized by ribosomal intergenic spacer analysis, and denaturing gradient gel electrophoresis (DGGE) or restriction fragment length polymorphism (RFLP) targeting group‐specific genes. SIR was not influenced by management and plant species, whereas denitrification enzyme activity was influenced only by plant species, and management–plant species interactions were observed for fixation and nitrification enzyme activities. Changes in nitrification enzyme activity were likely largely explained by the observed changes in ammonium concentration, whereas N availability was not a major factor explaining changes in denitrification and fixation enzyme activities. The structures of eubacterial and free‐living N2‐fixing communities were essentially controlled by management, whereas the diversity of nitrate reducers and ammonia oxidizers depended on both management and plant species. For each functional group, changes in enzyme activity were not correlated or were weakly correlated to overall changes in genetic structure, but around 60% of activity variance was correlated to changes in five RFLP or DGGE bands. Although our conclusions should be tested for other ecosystems and seasons, these results show that predicting microbial changes induced by management in grasslands requires consideration of management–plant species interactions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Plant traits – the morphological, anatomical, physiological, biochemical and phenological characteristics of plants and their organs – determine how primary producers respond to environmental ...factors, affect other trophic levels, influence ecosystem processes and services and provide a link from species richness to ecosystem functional diversity. Trait data thus represent the raw material for a wide range of research from evolutionary biology, community and functional ecology to biogeography. Here we present the global database initiative named TRY, which has united a wide range of the plant trait research community worldwide and gained an unprecedented buy-in of trait data: so far 93 trait databases have been contributed. The data repository currently contains almost three million trait entries for 69 000 out of the world’s 300 000 plant species, with a focus on 52 groups of traits characterizing the vegetative and regeneration stages of the plant life cycle, including growth, dispersal, establishment and pepersistence. A first data analysis shows that most plant traits are approximately log-normally distributed, with widely differing ranges of variation across traits. Most trait variation is between species (interspecific), but significant intraspecific variation is also documented, up to 40% of the overall variation. Plant functional types (PFTs), as commonly used in vegetation models, capture a substantial fraction of the observed variation – but for several traits most variation occurs within PFTs, up to 75% of the overall variation. In the context of vegetation models these traits would better be represented by state variables rather than fixed parameter values. The improved availability of plant trait data in the unified global database is expected to support a paradigm shift from species to trait-based ecology, offer new opportunities for synthetic plant trait research and enable a more realistic and empirically grounded representation of terrestrial vegetation in Earth system models.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Here we provide the 'Global Spectrum of Plant Form and Function Dataset', containing species mean values for six vascular plant traits. Together, these traits -plant height, stem specific density, ...leaf area, leaf mass per area, leaf nitrogen content per dry mass, and diaspore (seed or spore) mass - define the primary axes of variation in plant form and function. The dataset is based on ca. 1 million trait records received via the TRY database (representing ca. 2,500 original publications) and additional unpublished data. It provides 92,159 species mean values for the six traits, covering 46,047 species. The data are complemented by higher-level taxonomic classification and six categorical traits (woodiness, growth form, succulence, adaptation to terrestrial or aquatic habitats, nutrition type and leaf type). Data quality management is based on a probabilistic approach combined with comprehensive validation against expert knowledge and external information. Intense data acquisition and thorough quality control produced the largest and, to our knowledge, most accurate compilation of empirically observed vascular plant species mean traits to date.
LOTVS: A global collection of permanent vegetation plots Sperandii, Marta Gaia; de Bello, Francesco; Valencia, Enrique ...
Journal of vegetation science,
March/April 2022, 2022-03-00, 20220301, 2022-03, Volume:
33, Issue:
2
Journal Article
Peer reviewed
Open access
Analysing temporal patterns in plant communities is extremely important to quantify the extent and the consequences of ecological changes, especially considering the current biodiversity crisis. ...Long‐term data collected through the regular sampling of permanent plots represent the most accurate resource to study ecological succession, analyse the stability of a community over time and understand the mechanisms driving vegetation change. We hereby present the LOng‐Term Vegetation Sampling (LOTVS) initiative, a global collection of vegetation time‐series derived from the regular monitoring of plant species in permanent plots. With 79 data sets from five continents and 7,789 vegetation time‐series monitored for at least 6 years and mostly on an annual basis, LOTVS possibly represents the largest collection of temporally fine‐grained vegetation time‐series derived from permanent plots and made accessible to the research community. As such, it has an outstanding potential to support innovative research in the fields of vegetation science, plant ecology and temporal ecology.
We present LOTVS, a global collection of vegetation time‐series derived from the regular monitoring of plant species using permanent plots. Currently including 79 data sets from five continents and 7,789 time‐series monitored for at least 6 years and mostly on an annual basis, LOTVS has the potential to support timely and innovative research in vegetation science, plant ecology and temporal ecology.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
In a field experiment we have examined the effect of long-term grassland management regimes (
viz., intensive
versus extensive) and dominant plant species (
viz.,
Arrhenatherum elatius,
Holcus ...lanatus and
Dactylis glomerata) on soil organic carbon (SOC) build up, soil microbial communities using biomarker phospholipid fatty acids (PLFA), and the relationship between SOC and PLFAs of major groups of microorganisms (
viz., bacteria, fungi, and actinomycetes). The results have revealed that changes in SOC were not significantly affected by the intensity of management or by the plant species composition or by their interaction. The amount of PLFA of each microbial group was affected weakly by management regime and plant species, but the canonical variance analysis (CVA), based on individual PLFA values, demonstrated significant (
P
<
0.05) effects of management regime and plant species on the composition of microbial community. Positive and significant (
P
<
0.01) relationships were observed between PLFA of bacteria (
R
2
=
0.47), fungi (
R
2
=
0.33), actinomycetes (
R
2
=
0.71) and total microbial PLFA (
R
2
=
0.53) and SOC content.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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