Plant and Soil

Plant root cellular architecture and cell wall composition influence plant productivity, stress resilience, biotic interactions, and potentially soil carbon accumulation. This study establishes comprehensive compositional parameters for roots of a lowland switchgrass genotype, DVR3. Root traits were analyzed in 12.5 cm depth segments, from Zone 1 near the surface to Zone 4 down to 50 cm. Mean abundance ({micro}g/mg) for major cell wall components included cellulose 470 {+/-} 20, xylose 250 {+/-} 20, lignin 170 {+/-} 15, and total suberin 35 {+/-} 5. Composition and cellular anatomy varied with depth, in a partially coordinated manner. Cross sections showed extensive aerenchyma in mature root regions despite greater root mass density, corresponding to abundant lignin and cellulose. Deep roots were enriched for pectin-associated traits, including arabinogalactan II, homogalacturonan, and arabinose-associated linkages. Suberin content did not vary significantly, though Casparian strip formation, endoderm and exoderm thickening, and suberin surface staining progressed with development. Similar trends in root lignin and specific root length were observed for another lowland switchgrass genotype, AP13. These results suggest that it may be possible to genetically enhance native switchgrass root chemistry to promote soil penetration and below-ground carbon accumulation by reducing variability with development, potentially via cell-type specific adjustments. HighlightOlder, shallower switchgrass crown roots are enriched in lignin and cellulose, and deeper, younger roots are pectin-rich with juvenile cellular anatomy. A more uniform compositional distribution might enhance below-ground traits. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/744798v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@159de98org.highwire.dtl.DTLVardef@124d714org.highwire.dtl.DTLVardef@1a49c14org.highwire.dtl.DTLVardef@2fa67_HPS_FORMAT_FIGEXP M_FIG C_FIG Schematic summary of switchgrass root anatomy and composition across four 12.5-cm depth zones of a 50-cm root system. Zone 1 represents older, shallow roots and Zone 4 includes younger roots and root tips. Representative cross-sections show greater aerenchyma development in older roots than in young root tips. The compositional heatmap shows higher cellulose, lignin, and xylose in Zone 1, higher pectin and nitrogen in Zone 4, and relatively little variation in suberin across zones.

Alkaline and calcareous soils can induce iron (Fe) limitation in plants, yet the responses of root-associated microbial communities to beneficial rhizobacteria under these conditions remain poorly understood in cotton. Here, we investigated the effects of Variovorax paradoxus on plant performance, Fe nutrition, and root microbiome dynamics in cotton exposed to bicarbonate-induced Fe limitation. In this study, V. paradoxus inoculation under bicarbonate-induced Fe limitation significantly improved photosynthetic parameters, growth parameters, and tissue Fe status. Interestingly, V. paradoxus partially suppressed the Fe-deficiency-induced increase in root ferric-chelate reductase activity without further increasing rhizosphere siderophore activity. This response suggests that improved Fe availability reduced the demand for maximal activation of the intrinsic Strategy I response. Despite improved plant health, V. paradoxus reduced root C levels, suggesting altered belowground carbon utilization associated with bacterial inoculation and stress conditions. Split-root experiments further showed that inoculating both root compartments showed substantially greater recovery than unilateral inoculation, indicating that broader root exposure to V. paradoxus enhanced the beneficial response. Although bacterial alpha diversity remained unchanged, V. paradoxus significantly altered bacterial community composition and enriched Cellvibrio together with the fungal taxa Funneliformis and Dominikia under Fe limitation. Exploratory analysis identified the plant-beneficial fungal hubs Funneliformis and Serendipita in the V. paradoxus-treated community under indirect Fe deficiency, along with the core genera Pseudomonas, Hydrogenophaga, and Funneliformis and the indicator taxa Shinella and Aquabispora. Spearman correlation analysis further associated Streptomyces with root Fe accumulation and biomass, while Epicoccum and Sordariales were positively associated with siderophore production in cotton exposed to bicarbonate-induced Fe limitation and inoculated with V. paradoxus. These findings demonstrate the potential of V. paradoxus and identify candidate microbial partners for microbiome-informed biofertilizers to improve Fe nutrition in cotton grown in calcareous soils.

Background and aimsExcess nitrate (NO3-), from fertilizer overuse and intensive agriculture, can pollute water and contribute to greenhouse gas production (nitrous oxide - N2O). Plant metabolites from pastural herbs such as Plantago lanceolata (plantain) can inhibit microbial nitrification of ammonium to NO3- (biological nitrification inhibition - BNI) and change soil nitrogen cycle dynamics (lower potential nitrification rate - PNR). The main aim was to investigate differential plant metabolite expression associated with BNI and lowered PNR in different soil types. MethodsSix plantain cultivars were tested for BNI potential and screened for metabolites that correlated with inhibition of the ammonia oxidising bacterium (AOB) Nitrosospira multiformis. PNR and microbiome change was then investigated in four different New Zealand soils under the plantain cultivar Agritonic and ryegrass cultivar One50. ResultsPNR under plantain was 11 to 41% lower than fallow soil while PNR under ryegrass was 0 to 39% lower. In addition to verbascoside and aucubin, plantain metabolites associated with lower PNR included plantamajoside, riboflavin 3- and 5-sulfate, plantagoguanidinic acid. Chlorogenic acid was associated with lowered PNR under ryegrass. PNR reductions, microbiome structure and the ratio of ammonia oxidising archaea (AOA) relative to AOB was modulated by soil type. ConclusionPlantain and ryegrass lowered the PNR in four different soils and was correlated with metabolites beyond just aucubin and verbascoside. Based on candidate BNI-associated metabolites identified, it was hypothesised that lowered PNR is likely indirect through mechanisms such as chelation and appears to be dependent on both plant physiology and soil physicochemistry.

Despite their agricultural potential, how bacterial-fungal consortia reshape root microbiomes and improve crop performance in sorghum remains poorly understood. Here, we investigated how individual and combined inoculation with Bacillus subtilis and Trichoderma afroharzianum influenced sorghum performance and root microbiome assembly. The in vitro co-culture assay demonstrated the compatibility of B. subtilis and T. afroharzianum as a microbial consortium. The B. subtilis-T. afroharzianum consortium demonstrated the highest CPPI (composite plant performance index) and shoot fresh weight in sorghum, while all inoculation treatments improved multiple growth and physiological traits. Split-root analysis demonstrated that bilateral root co-inoculation was necessary to maximize whole-plant growth benefits. Also, B. subtilis-T. afroharzianum co-inoculation increased carbon levels in both roots and leaves, accompanied by enhanced rhizosphere siderophore production consistent with improved nutrient status. In microbial community analysis, neither bacterial nor fungal alpha or beta diversity differed significantly among treatments; instead, inoculation selectively restructured root microbial communities. The B. subtilis-T. afroharzianum consortium selectively enriched plant growth-promoting Actinoplanes, siderophore-producing Enterobacter, and the plant-beneficial fungal genus Podospora. Co-occurrence network analysis identified Rhodoplanes, Serendipita, and Zopfiella among hub taxa associated with B. subtilis-T. afroharzianum co-inoculation, suggesting potential roles in microbial community connectivity and organization. Furthermore, the persistence of Streptomyces and Serendipita, particularly the latter, suggests the presence of a beneficial microbial core that may contribute to sustained rhizosphere functioning. In addition, Bacillus and Serendipita were among the indicator taxa associated with inoculated treatment combinations, suggesting that the inoculants selectively assembled a distinct plant-beneficial microbiome. Devosia was associated with chlorophyll content, siderophore production, and shoot height, whereas Serendipita correlated with shoot biomass under the B. subtilis-T. afroharzianum co-inoculation. Taken together, B. subtilis-T. afroharzianum consortium promotes sorghum growth by selectively reshaping the root microbiome, highlighting its potential as a next-generation microbial biofertilizer.

Background and AimsAbiotic stress is a major constraint for citrus production in Mediterranean environments, where water deficit and salinity frequently occur. This is particularly relevant for perennial crops, like citrus, where limited options for stress avoidance exist. Rootstocks are extensively employed to enhance stress resilience; however, their influence on the root microbiome under abiotic stress remains largely unexplored. Here, we investigated the effects of water stress and salinity on the diversity, composition, and interactions of bacterial and fungal communities in two citrus rootstocks with reported contrasting phenotypes, such as Bitters, which has been described as exhibiting a promising tolerance to both water and salt stress, and Carrizo, which is generally reported to be highly sensitive to these conditions. MethodsThe distinct rootstocks have been subjected to either water stress or salt stress and compared with the non-stressed rootstocks. At the end of stress period, they were profiled and then integrated with recorded plant morphological (i.e. root volume), physiological (water potential, abscisic acid, chlorophyll and chlorophyll content meter) and biochemical measurements (abscisic acid and catalase). In parallel, we used a high-throughput amplicon sequencing to profile bacterial and fungal communities inhabiting the rhizosphere and endorhizosphere microhabitats of the rootstocks in both stresses and in non-treated conditions. Finally, we used correlations and multivariate analysis to determine relationships between plant performance and microbiome putatively underpinning stress adaptation and tolerance. ResultsAcross all treatments, microbial community composition was primarily shaped by microhabitat, with clear differentiation between rhizosphere and endorhizosphere. Abiotic stress significantly restructured microbial communities, particularly in the rhizosphere, while the endorhizosphere exhibited stronger genotype-dependent patterns. Bacterial communities showed pronounced stress-driven enrichments of taxa belonging to the main phyla (such as Proteobacteria, Actinobacteriota and Bacteroidota), with selective recruitment of taxa putatively associated with stress adaptation, whereas the response of fungal taxa (more represented by Ascomycota, Basidiomycota and Glomeromycota phyla) was less consistent and mainly microhabitat-driven. Notably, the two rootstocks exhibited distinct physiological strategies, with Bitters by increased proline accumulation and root volume and Carrizo characterized by enhanced ABA and catalase. ConclusionsOur findings showed Bitters outperform Carrizo in terms of tolerance to both water and salinity stress. In both rootstocks, specific bacterial taxa such as high abundant core or rare members, were associated with distinct phenotypic parameters, highlighting the importance of integrating plant and microbiome perspectives for improving stress resilience in citrus.

Smallholder farming systems in sub-Saharan Africa are constrained by declining soil fertility, erosion, and rising fertilizer costs, creating an urgent need for scalable inputs that sustain yields while maintaining soil health. While there is some evidence that microbial inoculants may offer a promising complement to conventional fertility management, field-scale evidence in tropical cereal and tuber systems remains limited. Here, we evaluated a multi-species inoculant composed of 20-22 Bacillus and Streptomyces species on potato and maize across four sites in Rwanda over two growing seasons (2025A and 2025B). Treatments included the inoculant applied at two rates (150 and 250 g ha-1), both alone and in combination with standard fertilization (inorganic fertilizer plus manure), alongside untreated and fertilized controls. Co-application of the inoculant with standard fertilization increased yield and plant biomass beyond fertilization alone, with gains of 6-51% for maize and 3-58% for potato. However, while the inoculant applied alone outperformed untreated controls, it generally did not match standard fertilization. Responses were strongest and most consistent for large-grade potato tubers, and application rate interacted with crop type, whereby the lower dose maximized marketable tuber yield, while maize showed a positive dose-response for grain and biomass. Yield increases were not accompanied by reductions in crop nutrient density, which was instead governed by site-level differences. Altogether, these results indicate that multi-species microbial inoculants are an effective complement to existing fertility practices that may offer, pending further research, a potential pathway to partial fertilizer replacement while sustaining productivity and nutritional quality in smallholder tropical agriculture.

Efficient nutrient and water management is crucial for enhancing crop productivity, soil health, and mitigating environmental losses in cereal cropping systems of semi-arid regions. A two-year field experiment was conducted to evaluate the effects of dairy manure annual application of 50 Mg ha-1 to maintain recommended fertilizer N, compared to sole urea application with two different irrigation regimes (100% and 75% ETc) on crop yield, water use efficiency, deep percolation, nitrate leaching, and soil quality within a wheat-fallow-maize rotation in Pakistan. Suction lysimeters installed at a depth of 1.2 m were used to collect nitrate-N leachates, while HYDRUS-1D was used to assess daily deep percolation losses. Results indicate that the interaction between manure and irrigation was significant for yield, nitrate-N leaching, and soil health. Manure with deficit irrigation showed wheat and maize yield of 4.36 and 7.80 Mg/ha, irrigation water use efficiency (WUEi) of 1.09 and 1.59 kg/ha/mm, respectively, with no significant increase observed with full irrigation; while a significant decrease was observed in the absence of manure, either with full irrigation or deficit irrigation. Manure with deficit irrigation averaged annual nitrate-N leaching of 17.45 kg/ha, while urea and manure with full irrigation averaged 11.46 and 55.59% increases in nitrate-N leaching losses, respectively, without any yield benefits. Our results indicate that deficit irrigation with manure produces optimum yield with reduced nitrate-N leaching risk and improved soil physical properties.

The reintroduction of extinct or endangered species to restore ecosystem function is an essential aspect of rewilding. The Wilder Blean Project at West Blean and Thornden Woods in Canterbury, UK, is committed to rewilding natural processes and enhancing biodiversity in one of England's oldest and largest areas of ancient woodland. The introduction of European bison (Bison bonasus) is an important part of the project. However, how the reintroduction of large herbivores influences local biodiversity and ecosystem functions during the early stages of rewilding remains poorly understood. Soil samples were collected from the same sampling sites before and two years after bison were reintroduced and profiled by metagenomic sequencing using Oxford Nanopore Technologies sequencing platforms. The results showed that the alpha diversity of soil organisms did not change significantly before and after the introduction of European bison, while beta diversity showed modest shifts in community composition. The relative abundance of some nitrogen-fixing and photosynthetic microbial genera showed declines in the 2024 Bison Area, while the mycorrhizal fungus genus Rhizophagus was significantly less abundant than in the 2024 Control Area. Despite relatively stable taxonomic diversity, functional composition differed significantly between the 2022 and 2024 Bison areas and among the 2024 rewilding treatments, revealing a decoupling between taxonomic diversity and functional composition. Amino acid synthesis pathways and carbon metabolism pathways were significantly enriched. These findings highlight the potential of long-read Oxford Nanopore metagenomics to reveal functional shifts that may not be apparent from taxonomic diversity alone. Although these early-stage responses cannot yet predict long-term rewilding trajectories, continued longitudinal monitoring integrating microbial, soil physicochemical, and ecosystem-level measurements will be essential to determine the persistence and ecological significance of these functional shifts.

Improving nitrogen use efficiency in maize (Zea mays) requires understanding how distinct root cell types and regulatory networks process fertilizer inputs. Given the current limited understanding of fertilizer-induced, cell-type-resolved maize roots and regulatory networks, computational biology frameworks are needed to model and predict how nutrient inputs are translated into transcriptional responses. Here, we integrated fertilizer-induced maize root bulk RNA-seq with reference atlases of single-cell RNA-seq and scATAC-seq to construct and predict a cell-specific regulome of the maize root under inorganic and mixed amendments. We demonstrate that inorganic fertilization induced stress associated and management pathways. Regulome analysis identified transcription factors (TF) from the AP2/ERF, NAC, HSF, and WRKY superfamilies that were preferentially active across root tissues. Deconvolution of the regulome onto single-cell atlases predicted core TF activity to the vascular cylinder and pith across both regimes, while mature cortex regulatory programs diverged. Construction of a gene regulatory network revealed that shared TF-target edges maintained the same regulatory orientation across fertilizer regimes. However, a small number of stress related TFs, including WRKY24, DREB1A, and NAC61, underwent a directional change between fertilization treatments. In silico knockout analysis predicted the activation targets for six of the seven regulators in their resident vascular/pith tissues, indicating the network behaves as a coherent, perturbable system. Additionally, soil metagenomic analysis showed that host soil microbial functions overlap with differentially expressed genes (DEGs) in shared functional categories, linking host regulome dynamics to rhizosphere processes. These findings and predictions suggest that the maize root regulome is spatially organized and dynamically reprogrammed by master regulators, predicting high-priority candidate nodes for engineering improved nutrient use efficiency.

Background: Resistance to protoporphyrinogen oxidase (PPO) inhibiting herbicides is mainly driven by diverse target-site mutations, reducing the effectiveness of this site of action in row crop systems. Fendioxypyracil is a newly developed PPO inhibitor with high intrinsic grass and broadleaf activity, but its performance against resistant populations and target-site enzyme variants remains insufficiently characterized. Results: Enzyme assays using PPO2 from Amaranthus palmeri and Setaria viridis demonstrated that fendioxypyracil maintained low IC50 values across a broad range of resistance associated mutations, including dG210 deletion and G210, R128, and G399 substitutions, whereas oxadiazon, tiafenacil, and saflufenacil showed substantial loss of potency. Greenhouse dose response experiments confirmed strong fendioxypyracil efficacy, with susceptible and G399A populations controlled at <3 g ai/ha, while dG210 and R128G populations showed only moderate shifts in sensitivity but remained effectively controlled at the recommended rate. Transgenic Arabidopsis thaliana expressing resistant PPX2 alleles exhibited faster and more severe injury with fendioxypyracil compared to saflufenacil. Field trials conducted in a PPO resistant Amaranthus palmeri population demonstrated that fendioxypyracil provided consistent weed control and density reduction, matching the performance of trifludimoxazin and saflufenacil while exceeding that of fomesafen. Conclusion: Fendioxypyracil provides robust and broad-spectrum activity against PPO resistant Amaranthus populations and target mutant enzymes, maintaining efficacy across diverse mutation backgrounds. These results demonstrate its potential as an effective tool for managing PPO inhibitor resistance and sustaining weed control in row-crop production systems.

Rhizomorphs are specialised, root-like fungal structures whose hierarchical organisation may offer a route to reinforcing mycelium-based materials, yet the environmental regulation of their network formation remains poorly understood. Here, we develop an image-based framework to characterise the longitudinal growth and organisation of Armillaria gallica rhizomorphs under varying nutrient availability and light exposure. Time-lapse imaging was combined with image segmentation, skeleton-based network analysis, optical measurements and Gompertz growth modelling. Nutrient availability produced a distinctly non-monotonic response. Moderate nutrient limitation (0.5 x standard concentration) favoured rapid and coherent exploratory growth, whereas intermediate enrichment (1.5 x) produced the greatest eventual network extent, reaching approximately 975 mm total strand length; network extent and radial expansion differed significantly across nutrient levels (padj = 0.0012). Further enrichment maintained substantial fungal coverage without additional network elaboration, consistent with a shift from long-range exploration towards more locally consolidating growth. By contrast, exclusion of ambient light produced no significant differences after multiple-testing correction. These results reveal a resource-dependent trade-off between exploration and network elaboration, demonstrate that fungal coverage and organised network formation are distinct outcomes, and provide a quantitative basis for controlling self-organised biological architectures for bio-derived material design.

Polycultures have long been practiced in traditional agriculture, yet their ecology-based benefits have remained underexplored. Here, under realistic conditions, we experimentally evaluated the productivity and ecological interactions in cultivated milpa, a traditional Mesoamerican polyculture of maize, squash and beans, using a substitutive design in which total plant density was held constant while varying species composition. Specifically, we asked whether productivity gains arose through complementary or selection effects, and whether these gains were associated with changes in arthropod communities and herbivory. We additionally evaluated whether prior cultivation influenced maize performance in the following season. Milpa plots produced significantly higher total yields, more than 2.6 times those of monocultures, despite poor bean performance. In particular, squash and maize equivalent yields increased approximately threefold. We found that these improvements were mainly explained by complementary effects rather than selection effects. Arthropod communities responded in species-specific ways to crop diversity, with predator abundance tracking herbivore presence. However, no consistent patterns emerged between herbivore load, predator abundance and plant damage, suggesting that belowground plant interactions may play a more important role than top-down herbivore control in explaining complementarity effects. In the following season, maize yield increased by [~]30% in plots previously planted with squash or beans, with milpa plots showing intermediate responses. These findings demonstrate that milpa can substantially enhance productivity while generating benefits that extend into the advantages and soil into the following growing season. Overall, our results suggest that complementarity among crops is the primary driver of productivity in milpa under low-input conditions.

The perennial grass Miscanthus x giganteus (miscanthus) offers a sustainable alternative to traditional biomass feedstocks while improving key soil health parameters, including aggregation. Aggregate stability results from dynamic soil-plant-microbe interactions, yet the relative importance of each factor remains an active research question. Building on previous observations that miscanthus alters soil structure to improve water-holding capacity and aggregate stability, we characterized the communities of soil bacteria and arbuscular mycorrhizal fungi (AMF) across three sites in Iowa, USA, comparing miscanthus to annual maize (Zea mays L.) and non-cropped perennial turfgrass (Poa spp.). We examined whether microbiomes co-varied with soil aggregation and, if so, whether plant cover identity or life history categorization better explained the observed patterns. Bacterial and AMF communities varied across sites and plant types, with signals that life history and plant cover identity both mattered. Aggregate stability aligned with a perennial-annual divergence in microbial beta diversity, while finer-scale differences in community composition and network structure were plant-specific. Soils under perennial plants were enriched in microbial groups positively correlated with aggregate stability; we identified 61 bacterial and 8 AMF "architect" taxa for future study. Within- and cross-kingdom co-occurrence network analysis revealed greater complexity under perennial plants: 1.9-fold more network links in miscanthus bacteria-bacteria networks than in maize, and 1.7-fold more in turfgrass AMF-AMF networks. Miscanthus fundamentally shapes microbial interactions, particularly among bacteria, relating to improved soil physical structure. Understanding these soil-plant-microbe feedbacks advances the development of biomass feedstocks with a portfolio of soil health benefits for next-generation biofuels and bioproducts. IMPORTANCEPerennial bioenergy crops can provide the raw material for biofuels and bioproducts while simultaneously improving soil health. Miscanthus x giganteus (miscanthus) efficiently stabilizes soil aggregates, potentially leading to higher water retention and erosion resistance. Understanding the microbial contributions to these outcomes is key to building resilient, sustainable bioenergy systems. This study highlights the connections between communities of soil microbes--bacteria and arbuscular mycorrhizal fungi--across three sites and three plant covers, including miscanthus, maize, and turfgrass. We identify a guild of potential "microbial architects" linked to soil aggregation and show more interconnected microbial networks under the perennial plant covers compared to annual maize. These insights shed light on the interactions between soil biological communities and soil physical and chemical properties. More broadly, the results may inform efforts to harness plant-associated microbiomes for sustainable biomass production.

Concurrent exposure to heat and drought stress compromises legume productivity, yet their combined effects are rarely quantified systematically. We compiled a database of 18 studies covering seven legume species. From these, we extracted 929 physiological, biochemical, and yield-related traits and calculated actual-to-additive ratios to classify heat-drought interactions as antagonistic (ratio < 1), additive (ratio = 1), or synergistic (ratio > 1). Additive heat-drought relationships accounted for 59 % of all classifiable observations, 37% relationships were antagonistic, and 4% synergistic. The relationship varied with species, genotype, trait, and experimental conditions highlighting the complexity of combined abiotic stress effects. The results challenge the common assumption that concurrent stresses invariably exacerbate damage and underscore the need for more realistic, quantitatively defined stress treatments as well as frameworks that integrate trait-level responses into predictive models of crop growth and development. Our synthesis provides a quantitative foundation to understand legume phenotypes under the increasingly frequent co-occurrence of heat and drought stress and identifies research areas where further work is needed to improve insight into combined stress responses. HighlightsO_LICombined heat and drought responses were mainly additive or antagonistic. C_LIO_LIEvidence is biased toward few legumes and controlled environments. C_LIO_LIField-based, multi-species studies are needed to identify adaptive traits. C_LI

Root-associated fungal (RAF) communities can influence tree nutrient acquisition and performance, yet their structuring factors and relationship with tree growth remain poorly understood, particularly near environmental treelines. We characterized root-associated fungal (RAF) communities on fine roots of white spruce (Picea glauca [Moench] Voss) in paired forest and treeline plots across two elevational and one moisture-limited treeline ecotones in Alaska. Using ITS2 DNA metabarcoding of fine root tips, we characterized individual RAF community alpha and beta diversity and tree growth based on basal area increment (BAI) over 5-30 years. As a result, sampling site was the strongest predictor of RAF composition, explaining 19.6% of variation, while soil pH explained an additional 11.7%. Treeline effects on RAF communities were weaker and context-dependent, with treeline trees showing distinct community composition in the Alaska Range, lower alpha diversity across all Hill numbers in Interior Alaska, and higher ECM relative abundance in the Brooks Range. RAF composition did not differ between fast- and slow-growing trees within sites. In contrast, alpha diversity was negatively associated with tree growth: OTU richness, Shannon and Inverted Simpson indices significantly predicted BAI over the previous 5, 10 and 15 years, with fast-growing trees supporting less diverse RAF and ECM communities. This relationship was strongest for recent growth and weakened with longer BAI averaging periods. Our results suggest that high growth of mature P. glauca is not necessarily associated with greater RAF or ECM diversity or specific taxa but may instead rely on fewer dominant or functionally effective fungal partners.

Optimum irrigation and fertilizer nitrogen (N) rates are important to improve crop yield at reduced environmental risks in the form of NO3-N leaching losses, without any financial loss. The study aimed to investigate the impact of rational irrigation and nitrogen management on wheat and maize crop yield vs. NO3-N leaching losses, with field experiments conducted at the experimental station, University of Agriculture Faisalabad, Pakistan, for two years, with wheat-fallow-corn seasons each year. Suction lysimeter were installed for collection of leachates while soil water balance was computed using the HYDRUS-1D model. We explored the various management strategies, including three irrigation and N levels (sub-optimal, optimal, and supra-optimal, referred to as I1, I2, and I3 for irrigation, and N1, N2, and N3 for nitrogen, respectively) for wheat and maize crops. The three irrigation levels were 325, 400, and 475 mm for wheat, and 375, 525, and 675 mm for maize crops. The three N-levels were 100, 130, and 160 kg ha-1 for wheat, and 220, 270, and 320 kg ha-1 for maize. The results indicated that increasing the irrigation and nitrogen levels significantly improved the growth and yield of both crops during both seasons. The highest grain yield of wheat (4.0 t ha-1) and maize (7.8 t ha-1) was observed with I3N3; however, I2N3 showed statistically no difference in yield, while showing significantly reduced (28.6%) annual NO3-N leaching losses of 23.8 kg ha-1, and the highest financial benefits of 780$. Sub-optimal levels of irrigation and N, though reduced the NO3-N leaching losses, caused significant yield losses, generally unacceptable to the farmers. Irrigation water use efficiency (WUEi) also improved by 12% in wheat and 20% in maize under I2 than that of the I3 level. Besides, considering economic profit, the highest value cost ratio (1.64 and 2.04 in wheat and maize, respectively) was achieved under the I2N3 treatment, as opposed to the other treatments. Based on comprehensive analysis, the I2N3 treatment is recommended for sustainable yield and minimal environmental risk in the wheat-maize cropping system. Moreover, it was observed that the rainy fallow period contributes 14.0-31.5% of the total NO3-N leaching losses. Further investigation is needed to minimize NO3-N leaching losses, especially during the rainy fallow period, by early maize sowing and increasing the efficiency of N fertilizer (such as fertilizer coating) under the flood irrigation system, to achieve the potential goals of sustainable productivity and environmental security.

Forest soils are an important source of volatile organic compounds (VOCs), yet little is known about how different tree species influence soil VOC emissions and the role of rhizosphere processes in mediating VOC release form roots. We analysed soil VOC emissions from the soil surface and bulk soil as well as from roots with intact rhizosphere and washed roots of Picea abies and Fagus sylvatica. Tree saplings were grown on natural forest soil, and VOC emissions and gas exchange of soils and roots were measured under controlled conditions using online gas analysers integrated into an automated system. To assess the contribution of rhizosphere soil and microbial communities to root VOC emissions, roots were analysed (a) without washing, preserving the rhizosphere, (b) water-washed, and (c) ethanol-washed (70 vol%) to minimize microbial contributions. Species-specific VOC emission patterns were observed in both soils and roots. P. abies showed higher total emission rates and a more diverse, terpenoid-rich VOC profile dominated by -pinene, {beta}-pinene, {beta}-myrcene, and -phellandrene than F. sylvatica. Notably, these differences were evident not only at the soil surface but also in root and litter free bulk soil. Root washing further revealed that the rhizosphere is a hotspot of terpenoid production in P. abies, with significantly higher monoterpenoid emissions from unwashed roots than from water or ethanol-washed roots. This study demonstrates how tree species shape net soil VOC emissions, potentially leading to cascading effects on atmospheric VOC concentrations, and highlights the importance of the rhizosphere in regulating belowground VOC production.

The physicochemical controls governing metal acquisition, release, and redistribution across biological interfaces remain poorly understood. Biophytometallurgy--the microbially assisted release and recovery of plant-associated metals--was used to probe the directionality of the mechanisms controlling nickel and rare earth element (REE) release from Phytolacca during solid-liquid extraction. Bulk characterization did not support a dominant crystalline REE-phosphate-like host in hydroponically enriched shoots. Dissolution and rebinding experiments instead revealed chemically accessible nickel and REE pools, the latter of which had behaviors consistent with apparent equilibrium-like partitioning under mildly acidic conditions. During sulfur biooxidation, Acidithiobacillus ferrooxidans promoted REE release while providing a competing cell-associated REE sink. Consequently, aqueous REE concentrations reflected net redistribution among the separable plant, solution, and microbial phases instead of dissolution alone. These results establish a framework for studying metal partitioning across complex and coupled biological systems and support a route for aqueous REE recovery from plants without thermochemical conversion to ash.

Drought and low temperatures are major abiotic factors affecting key physiological and biochemical processes and limiting the yields of soybean (Glycine max L. Merr.). To in-crease soybean production in Europe, different agricultural strategies are applied to re-duce abiotic stress, including biostimulants. Therefore, studies on the effectiveness of local strains isolated in Europe are becoming increasingly relevant. In this study two bacterial strains Arthrobacter pascens (AP) and Bradyrhizobium japonicum (BJ) along with plant-derived protein hydrolysate (PH) were analysed with soybean plans under abiotic stress conditions in plant growth chambers. Six treatments (control; AP; BJ; PH; BJ+AP; BJ+AP+PH) were tested to evaluate biostimulation effect before stress induction (VC stage) and to determine stress reduction effect on soybeans after plants recovery period (V3 stage). Biostimulants application has positive effect on soyabean biometric parameters in early plant development stage and post stress periods. More stable long-term effect was found on structural plant development parameters, than on pigment accumulation. The best results on plant biometric parameters were found where (AP) and (BJ+AP+PH) com-bination was inoculated. (BJ+AP+PH) combination was the only effective treatment, which showed significantly different results in pigments indices, compared to the control, after stress period. Author summaryYasha Jamil: Conceptualization, Data curation, Formal analysis, Writing- original draft, Giuseppe Colla: Formal analysis, Writing- original draft, Writing- review & editing, Justina Kaziuniene: Data curation, Formal analysis, Sarune Ramoskaite :Writing- review & editing. Monika Toleikien[e]: Conceptualization, Data curation, Formal analysis, Writing- original draft, Funding acquisition, Supervision, Writing- review & editing.

The increasingly severe droughts in the Amazon Basin make it urgent to understand the resilience of tropical tree species and their microbiota. Plant-associated fungi and bacteria (i.e. extended phenotype) modulate drought stress for their hosts, but their role in recovery dynamics remains poorly understood. To test the impact of different drought durations on the recovery of both physiology and microbiota of tropical trees, we followed the responses of nearly 1,000 seedlings belonging to seven tropical tree species of seasonally flooded (SF) forests in a greenhouse experiment. Seedlings were subjected to different droughts, reflecting a current, a projected and an extreme drought scenario of the French Guiana climate. Plant responses were monitored after the drought and after rewetting. Plant performance was estimated through leaf gas exchange, photochemical functioning, leaf water potentials and water-related traits as well as morphological traits. Bacterial and fungal leaf communities were characterized with respectively 16S and ITS2 markers using high-throughput sequencing. Increasing the duration of the drought reduced the ability of plants to recover physiological functions, with differences among species which were only partially predicted by their drought tolerance strategies. Bacterial diversity increased in most plant host species after mild drought but not under the most severe stress. Bacterial dispersion and turnover responses were strongly host species-specific, without a general directional pattern across species. Fungal communities showed greater compositional stability, but exhibited consistently higher turnover compared to bacterial communities during both drought and recovery, with no convergence toward control composition. Finally, none of the recovery networks mirrored the architecture of the control network, regardless of prior drought duration, demonstrating that the integrated extended phenotype does not recover even when individual traits show signs of recovery. Our results reveal that both physiological recovery and microbial community recovery are strongly shaped by the plant host species identity and drought duration This study widens knowledge of SF tropical forests, vulnerable habitats in the context of climate change, through the lens of the associated microbial communities and functional traits. Beyond the effects of an increasingly uncertain climate combined with a rise in the frequency of extreme events, our study places emphasis on including tree species extended phenotypes in considering their recovery dynamics.