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Infectious disease can shape community structure, particularly when pathogens affect foundation species. Seagrasses are foundation species that form meadows along coasts worldwide, controlling sediment deposition and biogeochemical cycling while supporting a diverse community of fish and invertebrates. These plants are hosts to wasting diseases that cause necrotic tissue lesions, which could alter seagrass value as food, habitat and mediators of ecosystem processes. However, such biotic interactions and influences on disease dynamics are still not well understood. We investigated whether a common herbivore affected the development of wasting disease on eelgrass. We measured the severity and prevalence of eelgrass wasting disease in a meadow across two summers through repeated field surveys. We assessed the role of the eelgrass herbivore on disease spread and growth using microcosm and mesocosm experiments. We further explored herbivore feeding preferences in a choice trial, which was paired with chemical analysis of plant tissue and analysed using a structural equation model. While the herbivore facilitates the growth of new disease lesions among isolated leaves, on balance they reduce lesion severity by more than 50% in comparison with no-herbivore controls in field-realistic settings. This was likely because the herbivore strongly prefers to eat diseased rather than healthy tissue, consuming nearly twice as much lesion area in choice trials. This preference arises from pathogen-driven changes in the host plant; lesioned tissue requires less force to penetrate than non-lesioned tissue. Additionally, as lesions increase in size, their polyphenolic concentrations drop, which further increases the magnitude of preference for lesioned tissue. Synthesis: These results suggest that these herbivores could help maintain disease in this system at a high prevalence (by facilitating disease development) but low severity (through preferential consumption), which is consistent with our field observations of nearly 100% prevalence and low severity in a natural bed where herbivore density is high. Describing such multi-species interactions in marine systems will advance our predictions of future disease states, as current understandings focus primarily on how environmental change contributes to pathogen outbreaks.

Defining plant development timing through seasonal growth and dormancy phases is a valuable proxy for studying climate change and serves as an annual bioindicator. However, current methods for determining the growing season vary due to species‐specific interpretations and differing understandings of its main drivers. Körner et al. (2023) introduced four non‐interchangeable definitions of growing seasons to clarify this complex issue. While some studies have paired different methods, none have simultaneously applied a full set of methods at the individual tree or species level. Here, I aim to present a new perspective to understanding growing season timing by focusing on all facets of above‐ground tree growth and measurable biological and phenological markers. This approach calls for simultaneous, continuous monitoring during active and dormancy periods on the same trees and across different species at a large spatial scale. The goal is to comprehensively understand each method's errors, temporal lags, and the factors determining each growing season, as defined by Körner et al. (2023, Ecology Letters, 26, 1277). Accurate estimation of growing season timing can reshape our understanding of its environmental drivers, improve terrestrial ecosystem models, assess the impact of climate change on tree growth, determine the biological zero for various species, verify remote sensing indices and forecast species distribution. [ABSTRACT FROM AUTHOR]

Pollen protein content has been demonstrated to be an essential nutritional component for bees and thus important in mediating plant–pollinator interactions. However, little is known on the drivers and consequences of among‐species variation in pollen protein content and how this can impact male and female reproductive success across plant species. Among‐species variation in resources allocated to pollen nutrition could further be constrained by life‐history strategies (e.g. survival‐reproduction trade‐offs) or evolutionary history. Here, we surveyed pollen protein content for 29 species within a diverse co‐flowering community and evaluated the effect of pollen protein on male and female reproductive success. We also tested the role of life history (annuals vs. perennials) and phylogeny in mediating differences in resource allocation to pollen nutrition. We found that pollen protein content influences components of male (bee visitor abundance and pollen dispersal) but not female (conspecific pollen deposition and pollen tube growth) reproductive success, suggesting this trait affects plants only via male function. This sex‐specific effect further suggests the potential for sexual conflicts driven by differential investment on this trait. We found no phylogenetic signal on pollen protein content. However, pollen protein content was higher in annual compared to perennial species suggesting survival versus reproduction trade‐offs also contribute to variation in pollen protein at the community level. Our study underscores the importance of understanding the ecological and evolutionary drivers of pollen protein content across plant species. Our results further suggest the existence of sexual conflicts and ecological trade‐offs mediated by differential investment in pollen nutritional quality, with important implications for community assembly and the structure of plant–pollinator interactions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Introduction: The leaf-height-seed (LHS) plant ecology strategy scheme posits that functional traits such as leaf size, stem height and seed mass play a key role in life history of plants. Although many studies have explored the LHS scheme across plant species, to our knowledge, no study has so far linked functional trait patterns across different plant clades. Methods: Here, we first explored the LHS scheme of several plant clades, i.e., palms, other monocots, dicots and gymnosperms, to understand how potential forces drive variation of plant functional traits. Results: We showed that phylogeny constrains plant functional traits and appears to be the most decisive factor that controls variation in seed mass irrespective of plant clades. Apart from phylogeny, a majority of variation in seed mass was explained by leaf size in palms clade, whereas by plant height in other monocots and dicots. Neither leaf size nor plant height well explained variation in seed mass of gymnosperms clade. Conclusion: Our study strongly suggests that different plant clades exhibit distinct LHS schemes, paving a new avenue for better understanding evolution and correlation between functional traits across sets of plant species. [ABSTRACT FROM AUTHOR]

BackgroundAimsMethodsResultsConclusionsSpecies constantly interact with many organisms simultaneously, and multiple species interactions can have unique effects when combined and potentially cause resource and fitness trade-offs to the host. For example, extrafloral nectar can be an effective defence against herbivory, yet this nectar production can be influenced by abiotic and biotic environmental factors, including other mutualisms.Here, we tested how traits associated with two different types of species interactions, herbivory and rhizobia-induced nodulation, may independently and interactively affect a host plant.We manipulated the presence or absence of rhizobia at two different levels of herbivory in the field. We measured multiple plant growth traits and fitness responses, such as plant height, above- and below-ground biomass, total biomass, the ratio between above- and below-ground biomass, rhizobia nodule number, and average nodule size, extrafloral nectar volume, extrafloral nectar sugar concentration, as well as ant and arthropod visitation to explore the potential ant-plant mutualism.Rhizobia inoculation did not affect ant or other arthropod visitation but did alter plant traits associated with growth as well as decreased allocation to sugar concentration within extrafloral nectar. Extrafloral nectar volume remained nearly constant in nearly all treatments, except for a decrease when plants did not have rhizobia and were not subjected to herbivory. Finally, increased herbivory led to reduced nodule size but did not alter nodule number, indicating potential shifts in resource allocation.Overall, multiple species interactions have compounding effects when combined, and plant traits alter differentially in response. In particular, we found a substantial benefit of rhizobia to the plants which did not result in either higher ant visitation or herbivory. However, greater herbivory did reduce plant growth, yet these effects varied depending on the presence or absence of rhizobia. This study demonstrates the importance of considering traits associated with multiple diverse species interactions simultaneously to better understand plant responses to environmental conditions. [ABSTRACT FROM AUTHOR]

Identifying the mechanisms underlying the persistence of rare species has long been a motivating question for ecologists. Classical theory implies that community dynamics should be driven by common species, and that natural selection should not allow small populations of rare species to persist. Yet, a majority of the species found on Earth are rare. Consequently, several mechanisms have been proposed to explain their persistence, including negative density dependence, demographic compensation, vital rate buffering, asynchronous responses of subpopulations to environmental heterogeneity, and fine‐scale source‐sink dynamics. Persistence of seeds in a seed bank, which is often ignored in models of population dynamics, can also buffer small populations against collapse. We used integral projection models (IPMs) to examine the population dynamics of Oenothera coloradensis, a rare, monocarpic perennial forb, and determine whether any of five proposed demographic mechanisms for rare species persistence contribute to the long‐term viability of two populations. We also evaluate how including a discrete seed bank stage changes these population models. Including a seed bank stage in population models had a significantly increased modeled O. coloradensis population growth rate. Using this structured population model, we found that negative density‐dependence was the only supported mechanism for the persistence of this rare species. We propose that high micro‐site abundances within a spatially heterogeneous environment enables this species to persist, allowing it to sidestep the demographic and genetic challenges of small population size that rare species typically face. The five mechanisms of persistence explored in our study have been demonstrated as effective strategies in other species, and the fact that only one of them had strong support here supports the idea that globally rare species can employ distinct persistence strategies. This reinforces the need for customized management and conservation strategies that mirror the diversity of mechanisms that allow rare species persistence. [ABSTRACT FROM AUTHOR]

Plant size is closely linked to its leaf trait characteristics, which are essential for determining its form and function. These relationships constitute a fundamental component of the global spectrum of plant diversity. Despite this, the size–trait relationships in coastal mangroves have often been overlooked, with a common assumption that they would mirror those found in terrestrial tropical trees. However, recent studies have begun to challenge this assumption, revealing unique adaptations and trait variations in mangroves that are influenced by their specific environmental conditions, such as salinity and nutrient availability. In this research, we investigated the leaf structural traits, plant height, and diameter at breast height or basal height (DBH) of 10 shrub and tree species. This study was carried out along an intertidal gradient within a mangrove forest located in Southeast China. We found that leaf traits differed significantly between shrubs and trees in their response to intertidal gradients, indicating that different species have evolved specific adaptations to thrive in their respective intertidal zones. This insight can help us decipher the selective pressures that have shaped trait evolution. Among all species, leaf carbon (C) economics (leaf dry mass content, leaf mass per area, and leaf density) decreased significantly with increasing plant height and DBH. For each growth form and intertidal zone, the relationships between plant size (height or DBH) and leaf C economics traits were consistent with those in the pooled dataset. Our study reveals that mangrove plants exhibit size‐related adjustments in leaf C economic strategies, indicating that plant size potentially acts as a proxy for the "slow–fast" continuum of plant performance. This discovery is pivotal for advancing our understanding of plant functional ecology and for enhancing the precision of global C cycle models, which are highly responsive to perturbations in atmospheric CO2 and climate change. [ABSTRACT FROM AUTHOR]

Field teaching is an essential component of botany and ecology; however, field classes were among the most likely to be cancelled during the early stages of the COVID-19 pandemic. Virtual alternatives that could be used to meet learning outcomes for botany (e.g. plant identification, surveying skills development) were largely unavailable at this time. To address this, a semi-immersive virtual botanical fieldtrip was developed using H5P. The resource consists of a 360 site tour, an interactive book with a series of interactive videos to mimic quadrat analysis and plant identification, and a plant identification guide to aid students in identifying species. Students responded largely positively to the resource, although they had a clear preference to undertake fieldwork in person in a more traditional manner. The resource is the first such virtual botanical fieldtrip and allows the retention of most learning outcomes for a traditional field class. This type of resource has considerable potential in a post-pandemic world to widen participation and let students experience ecosystems that they might otherwise not have the opportunity to investigate. The resource is available for use under a CC BY-NC-SA licence. [ABSTRACT FROM AUTHOR]

Integrated solutions to the climate and biodiversity crises—together with other global sustainability challenges—include the identification, design and implementation of nature‐based solutions (NbS). Living organisms mediate biogeochemical cycles and greenhouse gas fluxes from land and sea, and provide NbS to both climate change mitigation and adaptation. Plants, as the primary producers in ecosystems, lie at the heart of NbS.Plant ecology provides the foundation for developing and evaluating NbS based on an understanding of the ecological processes that underlie ecosystem service flow to people. In this Special Feature, we provide a collection of mini‐reviews that presents concise and focused analysis of the plant ecology of NbS. The mini‐reviews highlight key insights, challenges and opportunities for future research.The development of NbS that target specific ecosystem functions (e.g. carbon storage), or aim at increasing ecosystem resilience against perturbations (e.g. those associated with climate change), requires unification of ecological theory from areas such as biodiversity‐ecosystem function, plant–animal interactions, resilience and functional traits of organisms.Synthesis. Plant ecology and nature‐based solutions (NbS) research are complementary. Plant ecology can inform the design and management of effective NbS, and provide insights for the creation of novel ecosystems that provide NbS; while learning from the implementation of NbS can progress theory. To deploy NbS at the speed and scale needed to mitigate and adapt to climate change, we must rapidly integrate ecological concepts into the design of NbS. At the same time, the design and deployment of NbS in different ecological contexts provides an unprecedented opportunity to learn how performances of individual NbS sites can be explained in an integrated way, leading to the development of general concepts. Ultimately, a mechanistic understanding of how plants and their functional traits contribute to ecosystem function and service provision is critical for the design, verification of benefits from and avoidance of adverse effects of NbS. [ABSTRACT FROM AUTHOR]

Extreme drought and intensification of land use pose substantial threats to ecosystem stability. However, existing studies that assess ecosystem stability focus primarily on the stability of aboveground net primary productivity (ANPP), while the stability of belowground net primary productivity (BNPP) is often not considered.Here, we examined the response patterns and drivers of ANPP stability and BNPP stability in an alpine meadow to drought and clipping (simulating grazing and mowing) by the implementation of five levels of simulated precipitation (1/12, 1/4, 1/2, 3/4 and ambient precipitation) and clipping (unclipped vs. clipped) treatments over 7 years (2016–2022).The results showed that extreme drought decreased ANPP stability, while moderate drought increased BNPP stability and net primary productivity stability. The findings highlight the importance of jointly considering above‐ and belowground processes when evaluating ecosystem stability. Moreover, clipping did not have an impact on ANPP stability but reduced BNPP stability, and clipping differentially affected the stability of ANPP and BNPP in response to extreme drought. Furthermore, ANPP stability was largely determined by species temporal asynchrony rather than richness, whereas dominant species stability strongly contributed to the variation in BNPP stability of this alpine meadow faced with drought and clipping.Synthesis: In general, these results provide experimental evidence for the decoupling of the responses of above‐ and belowground productivity stability to extreme drought and clipping. Our findings indicate that aboveground responses should not be used as the sole indicator of the whole ecosystem consequences of extreme drought and disturbance factors such as grazing or mowing, emphasizing the need to evaluate ecosystem stability from a whole ecosystem perspective. [ABSTRACT FROM AUTHOR]

Mangroves are implemented as nature‐based solutions (NbS) for coastal protection, climate change mitigation (carbon sequestration) and other services. They play a core role in providing benefits for biodiversity, livelihoods and human well‐being.Ecological research has informed the use of mangroves as NbS, but failure of NbS projects has often been due to misconceptions about mangrove ecology and the limited use of the wide range of ecological knowledge available.Enhanced knowledge of the spatial and temporal variation in ecological processes, and differentiation among mangrove tree species and assemblages (including fauna and microbial communities) in the provision of ecosystem functions and services, will support successful use of mangroves as NbS.Knowledge of mangrove responses to the interacting pressures of climate change and human uses of the coastal zone will support resilient NbS projects.Synthesis. The success of mangroves as NbS can be improved with increased incorporation of knowledge of the ecology of mangrove plants, animals and microbes and by sharing and co‐producing knowledge within mangrove societies. [ABSTRACT FROM AUTHOR]

Like alien plant invasion, range expansion of native plants may threaten biodiversity and economies, rendering them native invaders. Variation in abiotic and biotic conditions across a large geographic scale greatly affects variation in traits and interactions with herbivores of native plant invaders, which is an interesting yet mostly unexplored issue. We used a common garden experiment to compare defensive/nutritional traits and palatability to generalist herbivores of 20 native (23.64° N–30.18° N) and introduced range (31.58° N–36.87° N) populations of Reynoutria japonica, which is a native invader following range expansion in China. We analyzed the relationships among herbivore pressure, climate, plant chloroplast haplotypes, leaf traits, and herbivore performance. Of the 16 variables tested, we observed range differences in 11 variables and latitudinal clines in nine variables. In general, herbivores performed better on the introduced plants than on the native plants, and better on the high‐latitude plants than on the low‐latitude plants within the introduced populations. Three key traits (leaf thickness, specific leaf area, and carbon‐to‐nitrogen [C:N] ratio) determined palatability to herbivores and were significantly associated with temperature and/or precipitation of plant provenance as well as with plant haplotypes but not with herbivore pressure. Our results revealed a causal sequence from plant‐range‐based environmental forces and genetic context to plant quality and palatability to herbivores in R. japonica. These findings suggest a post‐introduction evolution of R. japonica, which may partly explain the colonization success of this important native, but invasive plant. [ABSTRACT FROM AUTHOR]

Plant community ecology guides restoration of degraded lands, yet seed‐based restorations sometimes fail or result in unpredictable outcomes, necessitating a better understanding of community trajectory and stability. Western yarrow (Achillea millefolium) declined suddenly in two separate restoration projects after initial high relative abundance. To assess the potential role of soil pathogens, we surveyed plant and soil fungal communities in these restorations, and used an 8‐year‐old field experiment that crossed yarrow planted in varying densities with a fungicide treatment. Two greenhouse experiments then evaluated whether the suppressive effect in yarrow soil spread to native species used in restoration. Lower yarrow cover in a restoration project 5 years compared to 3 years after seeding coincided with higher relative abundance of fungal taxa that can cause disease, particularly Crown‐rot fungi (Paraphoma spp.). Paraphoma increased over time in experimental plots and coincided with yarrow decline. Decline onset was density‐dependent, occurring faster in plant communities where yarrow density was higher. Fungicide applications altered fungal pathogen communities and promoted yarrow cover relative to control plots. In the greenhouse, yarrow grew larger with fungicide, consistent with suppression of fungal pathogens. However, biomass of natives grown in yarrow‐conditioned soil was not affected by fungicides, suggesting pathogens did not spread. The rapid establishment and competitive nature of yarrow, followed by pathogen‐induced decline, make it an attractive early transitional "bridge species," so long as its pathogens are species‐specific. Our results suggest negative plant‐soil feedback can drive rapid decline of individual species, and considering plant–soil feedback could improve restoration predictability. [ABSTRACT FROM AUTHOR]

Large mammalian herbivores exert strong top‐down control on plants, which in turn influence most ecological processes. Accordingly, the decline, displacement, or extinction of wild large herbivores in African savannas is expected to alter the physical structure of vegetation, the diversity of plant communities, and downstream ecosystem functions. However, herbivore impacts on vegetation comprise both direct and indirect effects and often depend on herbivore body size and plant type. Understanding how herbivores affect savanna vegetation requires disaggregating the effects of different herbivores and the responses of different plants, as well as accounting for both the structural complexity and composition of plant assemblages. We combined high‐resolution Light Detection and Ranging (LiDAR) with field measurements from size‐selective herbivore exclosures in Kenya to determine how herbivores affect the diversity and physical structure of vegetation, how these impacts vary with body size and plant type, and whether there are predictable associations between plant diversity and structural complexity. Herbivores generally reduced the diversity and abundance of both overstory and understory plants, though the magnitude of these impacts varied substantially as a function of body size and plant type: only megaherbivores (elephants and giraffes) affected tree cover, whereas medium‐ and small‐bodied herbivores had stronger effects on herbaceous diversity and abundance. We also found evidence that herbivores altered the strength and direction of interactions between trees and herbaceous plants, with signatures of facilitation in the presence of herbivores and of competition in their absence. While megaherbivores uniquely affected tree structure, medium‐ and small‐bodied species had stronger (and complementary) effects on metrics of herbaceous vegetation structure. Plant structural responses to herbivore exclusion were species‐specific: of five dominant tree species, just three exhibited significant individual morphological variation across exclosure treatments, and the size class of herbivores responsible for these effects varied across species. Irrespective of exclosure treatment, more species‐rich plant communities were more structurally complex. We conclude that the diversity and architecture of savanna vegetation depend on consumptive and nonconsumptive plant–herbivore interactions; the roles of herbivore diversity, body size, and plant traits in mediating those interactions; and a positive feedback between plant diversity and structural complexity. [ABSTRACT FROM AUTHOR]

Over a century of research on pollinator cognition has shown that pollinators such as bees perceive and learn a multitude of floral stimuli and are capable of sophisticated decision-making using a variety of cognitive abilities. Research on pollinator cognition usually focuses on a single reward aspect in isolation, which does not reflect the complexity of reward types, chemistries, and attributes many pollinators encounter while foraging. Reward complexity can impact pollinators' perception, learning, and decision-making in interesting and sometimes unexpected ways. A cognitive perspective can shed new insight into the functions of floral reward complexity and bridge the fields of animal behavior and plant ecology. The cognitive ecology of pollination is most often studied using simple rewards, yet flowers often contain multiple types of chemically complex rewards, each varying along multiple dimensions of quality. In this review we highlight ways in which reward complexity can impact pollinator cognition, demonstrating the need to consider ecologically realistic rewards to fully understand plant–pollinator interactions. We show that pollinators' reward preferences can be modulated by reward chemistry and the collection of multiple reward types. We also discuss how reward complexity can mediate pollinator learning through a variety of mechanisms, both with and without reward preference being altered. Finally, we show how an understanding of decision-making strategies is necessary to predict how pollinators' evaluation of reward options depends on the other options available. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Protecting diversity is critical to maintaining functional and adaptive ecosystems. However, research groups that explore these relationships tend to lack diversity themselves. To address the challenges of our changing world, it is crucial to consider a wide range of perspectives and knowledge. We propose that just as greater diversity in ecosystems relates to a variety of functions and, consequently, enhances resilience, stability, and efficiency, a comparable diversity within research teams results in a broader spectrum of creative endeavors. Thus, it is important to re‐evaluate our scientific communities' openness toward greater diversity to meet the diverse problems of our changing world. Summary: Ecosystems face multiple threats, jeopardizing natural and human well‐being. Biodiversity loss can increase ecosystem vulnerability to global change, risking abrupt and irreversible changes. Protecting biodiversity can prevent ecosystems from crossing tipping points, preserving their functions and resilience, which sustain life on our planet. In addressing these challenges, society demands creativity, innovation, and diverse perspectives. Yet, our societal structures often neglect the full range of voices and experiences, limiting problem‐solving. Understanding how research teams with diverse demographics may stimulate creative solutions to global change challenges may help. In this context, we emphasize examples from plant ecology, where the advantages of diverse ecosystems are well recognized, and we draw an analogy of these features to the innovation of research teams. In ecosystems, biodiversity can maximize productivity and function but can also serve as a protective "insurance" against disruptions. Similarly, in a time of multifaceted environmental changes, diverse research groups play a critical and analogous role, resembling the biodiversity within ecosystems. Diverse research teams not only bring complementary strengths, fostering creative problem‐solving by embracing various perspectives, but also drive scientific innovation by integrating a wide range of research topics (e.g., ecosystems, taxa, and conservation priorities). These human‐centered dynamics are congruent with the mechanisms in ecosystems, with a diversity of solutions promoting resilience, stability, and efficiency, all of which ultimately provide a counterbalancing effect on global change. Much like biodiverse ecosystems, a diverse spectrum of knowledge, and expertise within the scientific community can enrich a dynamic landscape of innovation. [ABSTRACT FROM AUTHOR]

This article details the significance of Cycas revoluta in the cultural ecology of the Amami Islands, Japan. Although this plant was never domesticated, multiple lines of evidence elucidate a long history of its alimentary, ethnoecological, and symbolic saliency within Amami culture. Despite this fact, Amami cycad culture remains understudied and virtually unknown outside of Japan. This article summarizes previous and current research on the social roles and environmental significance of C. revoluta in the Amami Islands, with a specific focus on current threats to these plants and the cultural ecologies that surround them, including the ongoing biological invasion by the cycad aulacaspis scale. In doing so, the article seeks to highlight a unique form of biocultural heritage and ancestral cultural traditions that are in danger of being lost. It concludes with brief observations on potential avenues for future research that can both foment interest in and promote the holistic conservation of Amami cycad culture. [ABSTRACT FROM AUTHOR]

Summary: Understanding the drivers of assemblages of arbuscular mycorrhizal fungi (AMF) is essential to leverage the benefits of AMF for plant growth and health. Arbuscular mycorrhizal fungi are heterogeneously distributed in space even at small scale. We review the role of plant distribution in driving AMF assemblages (the passenger hypothesis), using a transposition of the conceptual framework of landscape ecology. Because rooting systems correspond to habitat patches with limited carrying capacity that differ in quality due to host‐preference effects, we suggest considering plant communities as mosaics of AMF microhabitats. We review how predictions from landscape ecology apply to plant community effects on AMF, and the existing evidence that tests these predictions. Although many studies have been conducted on the effect of plant compositional heterogeneity on AMF assemblages, they mostly focused on the effect of plant richness, while only a few investigated the effect of configurational heterogeneity, plant connectivity or plant community temporal dynamics. We propose key predictions and future prospects to fill these gaps. Considering plant communities as landscapes extends the passenger hypothesis by including a spatially explicit dimension and its associated ecological processes and may help understand and manipulate AMF assemblages at small spatial scales. [ABSTRACT FROM AUTHOR]

Summary: Integrating traits across above‐ and belowground organs offers comprehensive insights into plant ecology, but their various functions also increase model complexity. This study aimed to illuminate the interspecific pattern of whole‐plant trait correlations through a network lens, including a detailed analysis of the root system.Using a network algorithm that allows individual traits to belong to multiple modules, we characterize interrelations among 19 traits, spanning both shoot and root phenology, architecture, morphology, and tissue properties of 44 species, mostly herbaceous monocots from Northern Ontario wetlands, grown in a common garden.The resulting trait network shows three distinct yet partially overlapping modules. Two major trait modules indicate constraints of plant size and form, and resource economics, respectively. These modules highlight the interdependence between shoot size, root architecture and porosity, and a shoot–root coordination in phenology and dry‐matter content. A third module depicts leaf biomechanical adaptations specific to wetland graminoids. All three modules overlap on shoot height, suggesting multifaceted constraints of plant stature. In the network, individual‐level traits showed significantly higher centrality than tissue‐level traits do, demonstrating a hierarchical trait integration.The presented whole‐plant, integrated network suggests that trait covariation is essentially function‐driven rather than organ‐specific. See also the Commentary on this article by Li & He, 244: 337–340. [ABSTRACT FROM AUTHOR]

Quantifying the degree of ecological specialization of animals is essential for understanding the evolution of resource use in changing environments. Stable isotope analysis (SIA) is a powerful tool for investigating the ecological niches of animals and providing insights into their diet. This study focused on the ecological role of two coastal species of ants, Camponotus morosus and Dorymyrmex goetschi, in Chile. Their seasonal isotopic niches were characterised using carbon (δ13C) and nitrogen (δ15N) analysis. This was done on El Tabito Beach, a coastal area with a pronounced seasonality. The results indicated unique niches for each species and variation between them across seasons. While C. morosus maintained a consistent niche breadth throughout the year, D. goetschi displayed a narrower niche in summer. Our analyses showed that terrestrial-derived carbon constituted the primary food resource for both species of ants, with a slight increase in the marine component in summer. Overall, the results highlight seasonal variations in isotopic signatures, niche breadth, and diet composition and underscore the importance of considering temporal dynamics in ant ecology and, in particular, in trophic interactions. [ABSTRACT FROM AUTHOR]

Indonesia is one of the centers of sweet potato diversity worldwide. Sweet potatoes have the potential to be developed for food consumption. This research aims to determine the diversity of sweet potato cultivars, their morphological characteristics, and the relationships between local sweet potato cultivars in Bulungan Regency, North Kalimantan. The local sweet potato cultivars were selected using purposive sampling with the exploration method. The morphological characterization of the samples is based on IBPGR (International Board for Plant Genetic Resources) standards. Cluster analysis was conducted to identify the relationships using MVSP software version 3.1. The research identified 27 local sweet potato cultivars in Bulungan Regency. Morphological characterization revealed 41 characters that can differentiate each local sweet potato cultivar. The most influential characteristics include leaf shape, flower surface texture, the position of the stigma, flower surface color, back petal color, center shape and the number of lobes, primary leaf vein color, lobe type, main leaf bone color, stem internode length, and plant type. A flower shape that had not been discovered before, a pentagonal shape with curves, was identified. Cluster analysis divided the cultivars into two major groups with a coefficient range of 0.593 to 0.888 (59.3 to 88.8%). Cluster A consisted of one member, LK-7 (purple sweet potato), while Cluster B consisted of several subgroups with 26 local cultivars. The people of Bulungan Regency use these local cultivars for food, animal feed, and medicinal purposes. [ABSTRACT FROM AUTHOR]

Aim: Addressing how woody plant species are distributed in space can reveal inconspicuous drivers that structure plant communities. The spatial structure of conspecifics varies not only at local scales across co‐existing plant species but also at larger biogeographical scales with climatic parameters and habitat properties. The possibility that biogeographical drivers shape the spatial structure of plants, however, has not received sufficient attention. Location: Global synthesis. Time Period: 1997–2022. Major Taxa Studied: Woody angiosperms and conifers. Methods: We carried out a quantitative synthesis to capture the interplay between local scale and larger scale drivers. We modelled conspecific spatial aggregation as a binary response through logistic models and Ripley's L statistics and the distance at which the point process was least random with mixed effects linear models. Our predictors covered a range of plant traits, climatic predictors and descriptors of the habitat. Results: We hypothesized that plant traits, when summarized by local scale predictors, exceed in importance biogeographical drivers in determining the spatial structure of conspecifics across woody systems. This was only the case in relation to the frequency with which we observed aggregated distributions. The probability of observing spatial aggregation and the intensity of it was higher for plant species with large leaves but further depended on climatic parameters and mycorrhiza. Main Conclusions: Compared to climate variables, plant traits perform poorly in explaining the spatial structure of woody plant species, even though leaf area is a decisive plant trait that is related to whether we observe homogenous spatial aggregation and its intensity. Despite the limited variance explained by our models, we found that the spatial structure of woody plants is subject to consistent biogeographical constraints and that these exceed beyond descriptors of individual species, which we captured here through leaf area. [ABSTRACT FROM AUTHOR]

The proliferation of alien species that can suppress resident species via biotic interactions represents a growing concern worldwide. Yet, how above‐ and below‐ground communities simultaneously respond to plant invasion, particularly across large spatial scales, remains poorly explored. We hypothesized plant invasion has a greater impact on recipient above‐ and below‐ground communities at lower than higher latitudes given that biotic interactions play a more significant role in shaping communities in more favourable, lower latitude environments.To test this hypothesis, we conducted a comprehensive field survey of 124 sites spanning a 1700‐km latitudinal gradient in China, to explore the effects of invasion of Alternanthera philoxeroides, a globally widespread invasive plant, on plant, soil fungal and above‐ground arthropod communities.Invasion of A. philoxeroides had divergent effects on beta diversity (i.e. variation in taxa composition among sites) of plants, above‐ground arthropods and soil saprotrophic fungi, with negative, neutral and positive responses, respectively. Notably, the compositional dissimilarity of plant and arthropod communities between adjacent invaded and non‐invaded sites remained constant across latitudes. In contrast, the compositional dissimilarity of the entire and pathogenic fungal communities between adjacent invaded and non‐invaded sites increased with latitude. This resulted in a decreasing difference in invasion effects on the composition of plant and fungal communities with increasing latitude.Synthesis. Our study provides novel insights into the complexities of invasion effects by revealing contrasting responses of above‐ and below‐ground communities to plant invasion across latitudes. The contrasting responses could weaken or reshape above‐ and below‐ground interactions, and, in turn, affect future species invasions and the functioning of terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Summary: Even though they share many thematical overlaps, plant metabolomics and stable isotope ecology have been rather separate fields mainly due to different mass spectrometry demands. New high‐resolution bioanalytical mass spectrometers are now not only offering high‐throughput metabolite identification but are also suitable for compound‐ and intramolecular position‐specific isotope analysis in the natural isotope abundance range. In plant metabolomics, label‐free metabolic pathway and metabolic flux analysis might become possible when applying this new technology. This is because changes in the commitment of substrates to particular metabolic pathways and the activation or deactivation of others alter enzyme‐specific isotope effects. This leads to differences in intramolecular and compound‐specific isotope compositions. In plant isotope ecology, position‐specific isotope analysis in plant archives informed by metabolic pathway analysis could be used to reconstruct and separate environmental impacts on complex metabolic processes. A technology‐driven linkage between the two disciplines could allow us to extract information on environment–metabolism interaction from plant archives such as tree rings but also within ecosystems. This would contribute to a holistic understanding of how plants react to environmental drivers, thus also providing helpful information on the trajectories of the vegetation under the conditions to come. [ABSTRACT FROM AUTHOR]

Materials have been generalized and a systematic analysis of the elemental composition of 110 species and 28 families of plants that form the tree–shrub tiers of forest phytocenoses, as well as the structure of urban landscaping in southern Primorye, has been performed in this article. A high differentiation of the species composition in the accumulative abilities to the weight of the metal, especially Zn and Mn, is found. The most stable parameters among the species are recorded for the Cu content. The species and families of high, low, and background content of heavy metals are distinguished based on the author's indicator, i.e., "the relative intensity of accumulation (RIA)" of chemical elements. A low content of heavy metals is more typical for the main arboriflora composition. At the same time, about half of the studied species accumulate some metals above background (average) values. The maximum content of metals, exceeding background values five times or more, is recorded in leaves (needles) of the concentrator species: Zn, Salix udensis, Populus maximowiczii, P. nigra, P. tremula, and Syringa wolfii; Mn, Salix udensis, Sorbus pochuashanensis, and Picea sp.; and Fe, Crataegus pinnatifida. A high heavy metal content the families is the most typical for Hydrangeaceae and Salicaceae; a low content is typical for Fabaceae, Pinaceae, Tiliaceae, and Aceraceae; and the background level is typical for Rosaceae. Based on the results, a phytogeochemical systematics of the main species and families of arboriflora has been developed for the first time for the vegetation of the Russian Far East. [ABSTRACT FROM AUTHOR]

This research was carried out in Idlib Governorate, located in northwestern Syria, during the years 2021, 2022, and 2023. The self-environment of the Crataegus genus was also studied in the study areas, by conducting botanical surveys there, according to the Braun-Blanquet method. The results showed that Crataegus has environmental flexibility as it spreads in multiple bioclimatic environments. Specie Crataegus monogyna belonging to the order Quercetaliapubescentis, which follows the Querceteapubescentis order, whose components are part of the plant alliance Quercioninfectoriae. Which includes deciduous oak forests within the Supra-Mediterranean structure. As for the species C. azarolus, it belongs to the order Quercetaliailicis, which belongs to the class Querceteailicis, and whose components are considered within the botanical alliance QuercionCalliprini within the Eu-Mediterranean structure. In general, the hawthorn did not constitute a characteristic type of species, but was always accompanying species, and did not rise to the level of characteristic types of species included in the designation of plant communities specialized in it. [ABSTRACT FROM AUTHOR]

This study's main objective was to characterize the spontaneous vascular flora of the Asjen region and Brikcha forest. It was conducted in the study area Moroccan Atlantic North-1 (Man-1) in 2021-2022. The stratified sampling method combined with the records of the surface and itinerant survey methods were used as a basis to collect floristic data. Three hundred and eighty-four taxa belonging to 270 genera and 80 families were recorded, of which five species distributed among four families were new additions to the flora of the study area: Crepis vesicaria L. subsp. stellata (Ball) Babc and Scorzonera hispanica L. subsp. Hispanica (Asteraceae), Glinus lotoides L. (Molluginaceae), Juniperus oxycedrus L. subsp. oxycedrus (Cupressaceae) and Quercus coccifera L. (Fagaceae). The biological spectrum indicates the dominance of therophytes (47.66%), followed by hemicryptophytes (16.93%). Dicotyledons represent the most dominant systematic group (305 taxa, 79.43%), followed by Monocotyledons (72 taxa, 18.75%). Six families are dominant and represent 46.62% of all identified species: Asteraceae (61 species, 15.89%), Fabaceae (32 species, 8.33%), Poaceae (30 species, 7.81%), Lamiaceae (26 species, 6.77%), Apiaceae (17 species, 4.43%) and Caryophyllaceae (13 species, 3.39%). The most species-rich genus is Plantago, with six species, followed by Teucrium, with five species. The rate of endemism is 6.51%, with 25 species, eight of which are strictly endemic to Morocco. Rare or threatened species represent 3.12% of total species (12 species), with seven taxa on the national red list. [ABSTRACT FROM AUTHOR]

Background and aims – For some time now, the forests of the Sanaga basin in Cameroon have been threatened by the construction of numerous hydroelectric dams. In anticipation to this construction work, botanical surveys were carried out, resulting in the discovery of many species new to science. One of these certainly belongs to the genus Talbotiella in Leguminosae. Material and methods – This study is based on morphological observations on herbarium specimens, through detailed examination of 28 specimens of the new tree species as well as specimens of existing species of Talbotiella. Key results – Talbotiella couteronii is described and illustrated. The new species resembles Talbotiella batesii but has fewer leaflets, 5–10 pairs; an inflorescence usually with fewer flowers, 5–12; and flowers with longer pedicels, 10–20 mm long. Talbotiella couteronii is endemic to Cameroon, where it is restricted to the middle Sanaga basin in the Central Region and the Littoral Region. It occurs gregariously in periodically flooded riverine forests. Talbotiella couteronii is preliminarily assessed as Endangered following the IUCN Red List categories and criteria. The genus Talbotiella now consists of 10 species; of which six species are endemic to Cameroon. A comparative table summarizes the main vegetative characteristics of the 10 species. This treatment also includes an update of the description of T. bakossiensis.

Acid sulfate soils pose significant challenges to rice production due to their negative impact on root development and nutrient uptake, reducing rice yield and quality. The excessive use of fungicides by farmers to control rice diseases has exacerbated the issue, as it contributes to environmental pollution and poses health risks. Our study aimed to isolate indigenous bacteria from rice grown in acid sulfate soils with potential biocontrol activity against common fungal pathogens in Vietnam. Using 16S rRNA amplicon sequencing, a total of 91 bacterial strains were identified up to the genus level. Bacillaceae were predominant on healthy rice plants, whereas Pseudomonas spp. also occurred on plants infested with the rice blast pathogen Pyricularia oryzae. Genome sequencing, protein orthology, and multilocus sequence analyses revealed the presence of six taxonomic groups of Bacillaceae: Rossellomorea marisflavi (basionym: Bacillus marisflavi), Priestia megaterium (basionym: Bacillus megaterium), Priestia koreensis (basionym: Bacillus koreensis), Bacillus thuringiensis, Bacillus altitudinis, and Bacillus siamensis. Dual-culture assays showed that most strains had antifungal activity against Pyricularia oryzae, Rhizoctonia solani AG2-1, and Bipolaris oryzae, whereas only B. siamensis and two B. thuringiensis strains were active against Rhizoctonia solani AG1-IA. R. marisflavi strains were in general inactive. Genome mining identified various biosynthetic gene clusters associated with specialized metabolite production, some of which were linked to potential antimicrobial activity. Production of these metabolites was confirmed by chemical analysis. These results suggest that indigenous Bacillaceae strains from acid sulfate soils could be used as biocontrol agents for the sustainable management of rice diseases under acidic conditions.

Non-pathogenic bacteria can substantially contribute to plant health by mobilizing and supplying nutrients, providing protection against pathogens, and alleviating abiotic stresses. However, the number of genome-wide association studies reporting the genetic architecture of the response to individual members of the beneficial microbiota remains limited. In this study, we established a genome-wide association study under field conditions to estimate the level of genetic variation and the underlying genetic architecture among 162 accessions of Arabidopsis thaliana originating from 54 natural populations in the southwest of France in response to 13 strains of seven of the most abundant and prevalent non-pathogenic bacterial species isolated from the leaf compartment of A. thaliana in the same geographical region. Using a high-throughput phenotyping methodology to score vegetative growth-related traits, extensive genetic variation was detected among A. thaliana accessions in response to these leaf bacteria, at both the species and strain levels. The presence of crossing reaction norms between each strain and the mock treatment indicates that declaring a strain as a plant growth-promoting bacterium is highly dependent on the host genotype tested. In line with the strong genotype-by-genotype interactions, we detected a complex and highly flexible genetic architecture between the 13 strains. Finally, the candidate genes underlying the quantitative trait loci revealed significant enrichment in several biological pathways, including cell, secondary metabolism, signaling, and transport. Altogether, plant innate immunity appears as a significant source of natural genetic variation in plant–microbiota interactions and opens new avenues for better understanding the ecologically relevant molecular dialog during plant–microbiota interactions. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Needle pathogens cause the discoloration, death, or premature abscission of conifer foliage, reducing growth and vigor, and repeated defoliation may eventually result in tree mortality. Since 2016, forest managers in the southeast United States have reported the increasing scale, frequency, and severity of needle disease outbreaks on the region's principal timber species, loblolly pine (Pinus taeda L.). These recent outbreaks are raising concern throughout the region, as needle diseases are not traditionally considered a threat to P. taeda. Lecanosticta acicola (Thum.) Syd., the native causal agent of brown-spot needle blight, has been recovered from some outbreaks. However, the full array of fungi associated with symptoms has not been explored. In this research, P. taeda foliage was collected from affected stands throughout the region and analyzed to identify fungi associated with needle disease symptoms. We employed targeted molecular diagnostics to confirm the presence or absence of L. acicola and DNA metabarcoding to characterize the foliar mycobiome and screen for other potential pathogens. L. acicola was detected among symptomatic needles from multiple states, particularly in western portions of the P. taeda range, but rarely from stands in eastern states. Metabarcoding revealed pathogens in needles and identified associations among pathogenic fungi, differing symptoms (including needle discoloration and necrosis), and signs of fungal fruiting bodies. Additionally, the fungal community of needles varied with patterns of symptom presentation. This study is the first regionwide assessment of fungi associated with recent large-scale needle disease outbreaks on P. taeda and identifies multiple pathogens that warrant further study.

Microbial communities are essential for plant health, but using these relationships to enhance growth and pest protection is challenging. Leveraging the natural mechanisms plants employ to manage relationships with microbes is one promising means to selectively engineer whole microbial communities with beneficial properties. This approach, known as host-guided selection, has been successful in some model species targeting performance traits (e.g., biomass). However, few studies use crop plants or focus on defensive traits (e.g., pest resistance). Our goal was to naturally engineer tomato root-associated microbiomes that increase resistance to insect pests. First, we used an iterative soil microbial inoculation process to engineer insect-suppressive rhizosphere soil microbiomes that reduce damage from aphid feeding (Macrosiphum euphorbiae) or caterpillar defoliation (Manduca sexta, Spodoptera exigua). We then characterized the bacterial and fungal microbial communities of soils associated with differences in insect performance using metabarcoding approaches. Overall, soil microbiome selection produced transient differences in aphid performance, but caterpillar growth was unaffected. In four of nine generations, the aphid population growth rate was significantly lower on plants with rhizospheres selected for “low” insect performance, where abundance was reduced by up to 20%. Correspondingly minor shifts in fungal and bacterial relative abundance occurred in insect-suppressive communities. However, network analysis indicated that aphid feeding disrupted rhizosphere microbiome assembly, resulting in lower community complexity and connectivity and fewer structurally important taxa compared with uninfested controls. Overall, our results highlight critical factors for successful engineering of beneficial microbiomes, particularly insect feeding guild and microbial community stability.

Carrot cavity spot (CCS) has conventionally been managed with fungicides. However, fungicide resistance, their potential risks to human health and the environment, and the increasing demand for organic produce necessitate the exploration of biofungicides as alternatives. In this study, we evaluated varying concentrations of SoilGard (Certis USA, Columbia, MD), a Trichoderma virens-based biofungicide, for efficacy against different CCS-causing Pythium species in vitro. Additionally, its effects on taxonomic and functional diversities of soil fungal communities were studied in vivo in the greenhouse. To our knowledge, this is the first study reporting SoilGard's effectiveness against CCS, with emphasis on its potential as an alternative for fungicide-resistant Pythium isolates. Our in vitro study revealed that SoilGard efficacy was significantly dose-dependent and isolate-specific, thus highlighting the importance of selecting its application rate and the target isolate. Analysis of soil fungal communities using Illumina MiSeq sequencing revealed that SoilGard exerted a significant, albeit temporary, effect on the fungal community structure. It negatively impacted co-occurrence network complexity and alpha diversity in carrot-cultivated soil, whereas bare soil communities remained largely unaffected, thus explaining why preplant applications may yield better results. Our study showed that carrot cultivation without SoilGard enhanced fungal diversity, which was more pronounced late in the season, possibly due to carrot root-associated exudates. Our study sheds light on how complex interactions within soil fungal communities can be impacted by the application of beneficial/pathogenic microbes.

Plant-parasitic nematodes (PPNs) can be found deep in the soil profile, compounding nematode management decisions and detection. This study aimed to understand how seasonal fluctuations in edaphic factors are associated with the vertical distribution of PPNs in south Georgia's vegetable cropping systems. Five-core composite soil samples were taken monthly (March 2020 to February 2022) at three random locations in six vegetable fields. Fields represented three cropping systems (vegetable plasticulture, bare ground cucumber, and plastic bed watermelon rotation) and two regions (north and south) sampled from five 15-cm strata (0 to 15, 15 to 30, 30 to 45, 45 to 60, and 60 to 75 cm). Only soil temperatures and precipitation had seasonal fluctuations; the other edaphic factors were vertically stratified. Latitude and stratum had the strongest associations with nematode composition, showing a clear separation between the north and south regions. Variations in soil texture, porosity, moisture, and PPN vertical distribution suggested that the illuvial zone in the north region was the main factor in the differences observed between regions and strata. Seasonal fluctuations in vertical distribution were found among Meloidogyne incognita and Nanidorus spp. Higher abundances of deep-dwelling PPNs were limited to the south region in the winter for deep-dwelling M. incognita and summer and winter for Nanidorus spp., probably due to the illuvial zone barrier in the north region. Because most root-knot nematodes dwell at ≤30 cm during the summer, fumigant/nematicide applications are recommended during this season to minimize the risk of deep-dwelling escapees.

Sorghum bicolor is a promising bioenergy feedstock with high biomass production and unusual tolerance for stresses, such as water and nutrient limitation. Although the membership of the sorghum microbiome in response to stress has been explored, relatively little is known about how microbe–microbe networks change under water- or nutrient-limited conditions. This is important because network changes can indicate impacts on the functionality and stability of microbial communities. We performed network-based analysis on the core bacterial and archaeal community of an agronomically promising high biomass bioenergy genotype, Grassl, grown under nitrogen and water stress. Stress caused relatively minor changes in bacterial abundances within soil, rhizosphere, and endosphere communities but led to significant changes in bacterial network structure and modularity. We found a complete reorganization of network roles in all plant compartments, as well as an increase in the modularity and proportion of positive associations, which potentially could represent coexistence and cooperation in the sorghum bacterial/archaeal community under stress. Although stressors are often believed to be destabilizing, we found stressed networks were as or more stable than non-stressed networks, likely due to their redundancy and compartmentalization. Together, these findings support the idea that both sorghum and its bacterial/archaeal community can be resilient to future environmental stressors. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Huanglongbing (HLB, or citrus greening disease) affects all citrus varieties worldwide. In the United States, Asia, and South America, the causal agent is ‘Candidatus Liberibacter asiaticus’ (CLas), a phloem-limited, uncultured alphaproteobacterium. The hemipteran insect vector Diaphorina citri (Asian citrus psyllid) acquires and transmits CLas in a circulative, propagative manner. In addition to CLas, D. citri hosts multiple symbiotic bacterial species including Wolbachia (wDi). In D. citri, wDi has been sequenced and studied, but specific roles in D. citri biology are unknown. Using well-established quantitative PCR methods, we measured CLas titer in D. citri collected from four groves in central Florida with distinct HLB management strategies and tested whether CLas and wDi titer were correlated in a subset of these insects. Grove site had the largest effect on CLas titer. Sex had no effect on CLas titer, whereas a higher wDi titer was correlated with noninfected insects. Our results suggest that more directed follow-up research is necessary and important to clarify whether field management tactics influence CLas titer in D. citri and to better understand gene-by-environment interactions among D. citri, wDi, and CLas. Now that millions of trees in Florida have been treated with injectable formulations of oxytetracycline, which is likely to decrease bacterial populations in D. citri, this study may represent the last biologically meaningful snapshot of grove-level vector-pathogen ecology in the state during the HLB epidemic.

Plant parasitic nematodes pose a significant threat to food security. Management strategies for these pathogens are limited, and additional tools for their control are needed. Some fungi have shown promise for biocontrol; however, their success in the field has varied. In contrast, some fungal plant pathogens form synergistic associations with nematodes, resulting in increased plant disease severity. However, how the two groups of fungi change with different plant parasitic nematode abundances in the soil is underexplored. In this study, we used the soybean cyst nematode as a model to understand these changes. We sampled soil from 171 Ohio soybean fields in 2019 and 2021 and determined soybean cyst nematode abundance. We identified the fungi in the samples through amplicon sequencing of the 18S-ITS rDNA regions. Edaphoclimatic factors were used to classify samples into geographic regions to account for environmental differences between sampling locations. We hypothesized that fungal communities would be influenced by both region and soybean cyst nematode abundance. K-near-neighbor analysis revealed that fungal communities follow regional patterns. We also found that soybean cyst nematode abundance was associated with changes in these communities regardless of the region. Two potential nematophagous fungi were found to be prevalent in Ohio through core community analysis, although they were enriched when soybean cyst nematode abundance was high. Finally, differential network analysis showed that interactions among fungal community members change when soybean cyst nematode is present in the soil. Together these results suggest that this nematode significantly shifts the fungal community composition in field soils. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

In Western France, rapeseed (Brassica napus) cultivation faces substantial yield losses due to the root holoparasitic plant Phelipanche ramosa. However, recent observations have shown a reduction in parasitism within previously heavily infested fields. This study investigates two neighboring rapeseed soils with distinct levels of parasitic infestation, considered suppressive and conducive. Using a cocultivation system of Brassica napus and P. ramosa, we comprehensively examined rhizosphere exudates, parasitic plant attachment, and rhizosphere soil microbiota. Our findings revealed that the suppressive soil effectively reduced parasitism by impeding broomrape attachment and development, as well as inducing necrosis of tubercles. This suppressive effect was specific to postattachment stages, leaving germination and haustoriogenesis preattachment stages unaffected. Analysis of microbial structures suggested that the suppression of parasitism is predominantly of fungal rather than bacterial origin. Correlation network analyses identified three groups of amplicon sequence variants (ASVs) associated with suppression. Notably, seven ASVs were inversely correlated with parasitic attachments, and only one ASV, identified as Berkeleyomyces, a necrotrophic fungus responsible for black root rot, was positively correlated with necrosis and was more abundant in the suppressive soil. This study demonstrates the contrasting parasitic plant development on two physicochemically similar soils, highlighting the central role of fungal dynamics in the rhizosphere. These results provide valuable insights into the mechanisms underlying soil-mediated suppression of P. ramosa, offering potential strategies for mitigating the impact of this root holoparasite on rapeseed yields in the region.

Studies of plant–microbe interactions using synthetic microbial communities (SynComs) often require the removal of seed-associated microbes by seed sterilization prior to inoculation to provide gnotobiotic growth conditions. Diverse seed sterilization protocols have been developed and have been used on different plant species with various amounts of validation. From these studies it has become clear that each plant species requires its own optimized sterilization protocol. It has, however, so far not been tested whether the same protocol works equally well for different varieties and seed sources of one plant species. We evaluated six seed sterilization protocols on two different varieties (Sugar Bun and B73) of maize. All unsterilized maize seeds showed fungal growth upon germination on filter paper, highlighting the need for a sterilization protocol. A short sterilization protocol with hypochlorite and ethanol was sufficient to prevent fungal growth on Sugar Bun germinants; however a longer protocol with heat treatment and germination in fungicide was needed to obtain clean B73 germinants. This difference may have arisen from the effect of either genotype or seed source. We then tested the protocol that performed best for B73 on three additional maize genotypes from four sources. Seed germination rates and fungal contamination levels varied widely by genotype and geographic source of seeds. Our study shows that consideration of both variety and seed source is important when optimizing sterilization protocols and highlights the importance of including seed source information in plant–microbe interaction studies that use sterilized seeds. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Protists are abundant in the rhizosphere, and protist inoculation onto plants has revealed protists’ roles in plant growth and development, disease suppression, and relationships with plant-beneficial bacteria. In this study, we evaluated the establishment of an 18-member defined protist consortium after inoculation onto germinated maize seedlings, along with the effects on the bacterial populations in the rhizosphere. Inoculated protists established a community that could be detected in the rhizosphere 3 weeks after inoculation. Plants inoculated with the protist consortium developed a bacterial community structure similar to that of plants inoculated with protist-free rhizosphere bacteria but different from that of uninoculated plants. This indicates that the protist cultures introduced rhizosphere-competent bacteria to the seedling. We also observed a plant growth phenotype, as inoculation with rhizosphere bacteria suppressed plant growth in the absence, but not the presence, of protists. Maize inoculated with an antibiotic-treated protist had lower biomass than plants inoculated with an untreated protist, indicating that growth promotion by protists depended on bacteria in the protist culture microbiome. This study shows that inoculation of germinated seeds establishes protist and bacterial communities on maize roots and that plant-detrimental effects of rhizosphere bacteria can be mitigated by the presence of protists.

Plant-parasitic nematodes are important pathogens of agricultural crops. Of particular importance are cyst nematode species of Globodera and Heterodera, which remain a major constraint to global production of crops such as potato, soybean, and wheat. Recent restrictions on the use of some synthetic nematicides has created an urgent need for alternative methods of controlling cyst nematodes. This project aimed to (i) document fungi found associated with cyst nematodes, (ii) determine if the fungi associated with cyst nematodes are dependent on growth conditions or nematode species, (iii) identify core mycobiomes for each of the eight cyst nematode species, (iv) identify the core mycobiome across all cyst nematode species studied, and (v) determine if the fungi associated with Globodera species are structured geographically. Sixty cyst nematode populations from eight species—Globodera sp., G. ellingtonae, G. pallida, G. rostochiensis, H. avenae, H. carotae, H. glycines, and H. schachtii—were collected from several geographic locations globally and screened for fungi using both culture-dependent and -independent methods. The core mycobiome was determined for each species. In total, 744 species of fungi were found to be associated with cyst nematodes. Fungal species shared across all cyst nematode species included Pochonia sp., Sporothrix sp., Neocosmospora solani, Exophiala equina, Mortierella sp., and Sarocladium kiliense. The core mycobiomes were conserved between cyst nematode species irrespective of their geographic origin. Cyst nematodes collected from the field or from greenhouse cultures also recruited similar core mycobiomes. These findings could be relevant when choosing fungi to evaluate as biocontrol agents against cyst nematodes.

Bacterial biocontrol agents that antagonize soilborne pathogens are increasingly considered alternatives to chemical pesticides, but their in vivo efficacy is often inconsistent, restricting commercial use. The efficacy of a biocontrol agent can depend on rhizosphere competence and its interaction with native microbiomes, which can affect ecosystem functioning. This study investigated the capacity of a Bacillus cereus sensu lato biocontrol strain (S-25) to persist on roots and in the rhizosphere of cucumber and evaluated its impact on bacterial and fungal community composition in the rhizosphere in the absence and presence of Rhizoctonia solani, the causative agent of damping-off disease in young seedlings. Following amendment, S-25 abundance in the cucumber rhizosphere decreased by two orders of magnitude but remained relatively high for the duration of the experiment, in contrast to the root surface, where it was not detected. Amendment with S-25 significantly reduced the incidence of disease caused by R. solani without reducing the relative abundance of the fungal pathogen. Interestingly, R. solani did not substantially alter the rhizosphere microbial community, whereas S-25 reduced bacterial diversity and facilitated a shift in community composition, with increased relative abundance of Acidobacteriota and Actinomycetota, and reduced abundance of Pseudomonadota, Bacteroidota, and Verrucomicrobiota. Collectively, this study provides important insights into the mode of persistence of biocontrol agents and their effect on native microbiomes in the rhizosphere of pathogen-inoculated plants. It demonstrates that amendment can significantly alter local microbiomes and suggests that optimizing amendment regimes or selecting strains with higher rhizosphere competence can enhance future biocontrol agents.

Classical approaches to plant disease diagnosis assume a single pathogen/single disease paradigm. Here, we revisit the presumed role of Fusarium oxysporum as the causal agent of wilting and yellowing of chickpea plants on smallholder farms in Ethiopia. Contrary to expectations, detection of Fusarium DNA using conserved PCR primers failed to associate the pathogen with symptomatic plants. Instead, culture-independent sequencing of microbial communities nominated unexpected pathogens and revealed patchiness in the assembly of common microbial consortia. Surprisingly, tests of differential enrichment identified Phytophthora as the most common disease-associated taxon. More generally, across all field sites, multilevel pattern analysis identified indicator taxa whose patterns of co-occurrence demarcate discrete microbial communities and are consistent with a range of specific interactions, including mutualism and antagonism. Taken together, these data indicate that soilborne chickpea disease in Ethiopia has heterogeneous origins and that despite decades of emphasis and disease resistance breeding, the role of Fusarium as the frequent agent of chickpea disease in Ethiopia remains enigmatic.

Tsuga canadensis (eastern hemlock) is an important tree species in North America, but it has been subject to threats from invasive insects such as Adelges tsugae (hemlock woolly adelgid). A. tsugae is native to Asia, and Tsuga species from Asia are typically resistant to this insect. In this study, we examined the phyllosphere microbiome of two hemlock species native to North America and susceptible to A. tsugae (T. canadensis and T. caroliniana) as well as two species native to Asia and resistant to A. tsugae (T. chinensis and T. diversifolia). Because pesticide application is often used to treat native Tsuga species impacted by A. tsugae, we also examined the response of the microbiome and overall plant physiology to the pesticide dinotefuran in T. canadensis. We found significant differences in the bacterial and fungal microbiome among the four species of Tsuga. Dinotefuran also significantly affected bacterial communities, but not fungal communities, of T. canadensis. The genus Methylobacterium, which uses methanol produced during plant cell elongation and growth, was a significant indicator of trees not subject to dinotefuran. This suggests that dinotefuran may have reduced cell growth in treated trees. Despite changes in the microbiome, dinotefuran application did not significantly affect plant physiology; however, the coefficient of variation in dinotefuran-treated trees was larger than that in non-treated trees. Our results suggest that the microbiome could play a role in mediating insect resistance in Tsuga species and that pesticide application could affect the phyllosphere microbiome, with implications for plant growth and resistance. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Glyphosate, the active ingredient of glyphosate-based herbicides (GBHs), controls the growth of weeds by inhibiting the shikimate pathway, thereby interrupting amino acid biosynthesis in plants. However, several microbes have the shikimate pathway, and the effect of glyphosate on these non-target organisms is ignored. The action of GBHs is further complicated when used with other agrochemicals, such as phosphate fertilizers, often varying their mode of action depending on soil type or plant species. To address the impact of GBHs and phosphate fertilizers, we simulated agricultural application of GBHs and phosphate fertilizers in a field study, investigating the composition of endophytic microbial communities and correlation of phytohormone concentrations with the microbial diversity of potato (Solanum tuberosum). In leaves, glyphosate residues in soil from GBH treatment alone and in combination with phosphate significantly shifted the bacterial community, whereas phosphate alone and in combination with glyphosate significantly altered the composition of the fungal community. There were no significant changes in microbial communities in roots and tubers. Plants treated with GBHs showed higher ratios of potentially glyphosate-resistant bacteria, with Xanthomonadaceae and Moraxellaceae being more abundant. Additionally, phytohormone concentrations showed various correlations with bacterial and fungal diversity in different treatments. The study highlights the impact of GBH residues in soil, particularly in combination with phosphate fertilizers, on the composition of plant-associated microbial communities. Together with changes in phytohormone concentrations, plant health may be affected. Future studies could provide insights into whether these agrochemicals influence the plant microbiome, leading to changes in phytohormones or vice versa. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Phytobiomes Vol. 8 No. 4

Grapevine productivity worldwide is increasingly threatened by global warming, potentially exacerbating water scarcity. This study examines drought's effects on grapevine xylem fungal communities, particularly regarding Phaeomoniella chlamydospora, linked to esca and Petri diseases. Investigating 1-year-old grafted grapevines under varied water regimes, including severe, moderate, and no water deficit, the research assessed how drought influences fungal diversity, structure, and interactions within the xylem. Utilizing internal transcribed spacer high-throughput amplicon sequencing and droplet-digital PCR, the study tracked changes in fungal composition and P. chlamydospora prevalence over two growing seasons. The induced water stress not only altered the diversity and composition of the fungal microbiome in the xylem vessels but also affected co-occurrence networks, resulting in less complex networks with fewer correlations between taxa, potentially increasing grapevine vulnerability to various biotic and abiotic stresses. Severe water deficit significantly reduced microbial diversity, leading to a shift in the abundance of pathotrophs such as P. chlamydospora in the xylem. This underscores the interconnectedness between water stress, microbiome dynamics, and plant health. The combination of compromised plant defenses, altered physiological conditions, and shifts in the surrounding microbial community may create conditions conducive to increased P. chlamydospora abundance in the xylem vessels of young vines following water stress.

The new extinction risk assessments of the mosses of Serbia have been completed. Based on the available data, 27.18% of Serbian moss flora (174 species) is under threat (status 2024). Nearly 20% (129 species) of Serbian moss flora is considered to be Data Deficient (DD) and 5.16% (33 species) Near Threatened (NT). These findings clearly indicate the urgent need for field investigation and species biology research in order to define the major threats and adequate conservation measures.

The agricultural industry is constantly searching for new solutions to increase the productivity and nutritional value of crops under various conditions. Microbial inoculants have emerged as an alternative to traditional chemical fertilisers which could enhance crop productivity in acid soils - a major problem in modern agriculture. The aim of this research was to evaluate the effects of Bacillus megaterium and Mesorhizobium sp. on the seed germination of bird’s foot trefoil and orchardgrass under low pH (in vitro), as well as the nutrient composition of plants grown in acid soil. A positive impact of bacterial inoculation on seed germination was observed at pH 5 and 6 for both plant species. The content of macro- and microelements was within the range of optimal values for both plant species. This research provides valuable insights into the potential benefits of using bacterial inoculants to improve the seed germination and nutrient composition of plants grown in acid soils.