Integrating perspectives in developing mycorrhizal trait databases: a call for inclusive and collaborative continental efforts.

Global assessments of mycorrhizal symbiosis present large sampling gaps in rich biodiversity regions. Filling these gaps is necessary to build large-scale, unbiased mycorrhizal databases to obtain reliable analyses and prevent misleading generalizations. Underrepresented regions in mycorrhizal research are mainly in Africa, Asia, and South America. Despite the high biodiversity and endemism in these regions, many groups of organisms remain understudied, especially mycorrhizal fungi. In this Viewpoint, we emphasize the importance of inclusive and collaborative continental efforts in integrating perspectives for comprehensive trait database development and propose a conceptual framework that can help build large mycorrhizal databases in underrepresented regions. Based on the four Vs of big data (volume, variety, veracity, and velocity), we identify the main challenges of constructing a large mycorrhizal dataset and propose solutions for each challenge. We share our collaborative methodology, which involves employing open calls and working groups to engage all mycorrhizal researchers in the region to build a South American Mycorrhizal Database. By fostering interdisciplinary collaborations and embracing a continental-scale approach, we can create robust mycorrhizal trait databases that provide valuable insights into the evolution, ecology, and functioning of mycorrhizal associations, reducing the geographical biases that are so common in large-scale ecological studies.

Review of Explosive Contamination and Bioremediation: Insights from Microbial and Bio-Omic Approaches.

Soil pollution by TNT(2,4,6-trinitrotoluene), RDX(hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane), and HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), resulting from the use of explosives, poses significant challenges, leading to adverse effects such as toxicity and alteration of microbial communities. Consequently, there is a growing need for effective bioremediation strategies to mitigate this damage. This review focuses on Microbial and Bio-omics perspectives within the realm of soil pollution caused by explosive compounds. A comprehensive analysis was conducted, reviewing 79 articles meeting bibliometric criteria from the Web of Science and Scopus databases from 2013 to 2023. Additionally, relevant patents were scrutinized to establish a comprehensive research database. The synthesis of these findings serves as a critical resource, enhancing our understanding of challenges such as toxicity, soil alterations, and microbial stress, as well as exploring bio-omics techniques like metagenomics, transcriptomics, and proteomics in the context of environmental remediation. The review underscores the importance of exploring various remediation approaches, including mycorrhiza remediation, phytoremediation, bioaugmentation, and biostimulation. Moreover, an examination of patented technologies reveals refined and efficient processes that integrate microorganisms and environmental engineering. Notably, China and the United States are pioneers in this field, based on previous successful bioremediation endeavors. This review underscores research's vital role in soil pollution via innovative, sustainable bioremediation for explosives.

Exploring the mycobiome and arbuscular mycorrhizal fungi associated with the rizosphere of the genus Inga in the pristine Ecuadorian Amazon.

This study explored the composition of the mycobiome in the rhizosphere of Inga seedlings in two different but neighboring forest ecosystems in the undisturbed tropical Amazon rainforest at the Tiputini Biodiversity Station in Ecuador. In terra firme plots, which were situated higher up and therefore typically outside of the influence of river floods, and in várzea plots, the lower part of the forest located near the riverbanks and therefore seasonally flooded, tree seedlings of the genus Inga were randomly collected and measured, and the rhizosphere soils surrounding the root systems was collected. Members of the Fabaceae family and the genus Inga were highly abundant in both forest ecosystems. Inga sp. seedlings collected in terra firme showed a lower shoot to root ratio compared to seedlings that were collected in várzea, suggesting that Inga seedlings which germinated in várzea soils could invest more resources in vegetative growth with shorter roots. Results of the physical-chemical properties of soil samples indicated higher proportions of N, Mo, and V in terra firme soils, whereas várzea soils present higher concentrations of all other macro- and micronutrients, which confirmed the nutrient deposition effect of seasonal flooding by the nearby river. ITS metabarcoding was used to explore the mycobiome associated with roots of the genus Inga. Bioinformatic analysis was performed using Qiime 2 to calculate the alpha and beta diversity, species taxonomy and the differential abundance of fungi and arbuscular mycorrhizal fungi. The fungal community represented 75% of the total ITS ASVs, and although present in all samples, the subphylum Glomeromycotina represented 1.42% of all ITS ASVs with annotations to 13 distinct families, including Glomeraceae (72,23%), Gigasporaceae (0,57%), Acaulosporaceae (0,49%). AMF spores of these three AMF families were morphologically identified by microscopy. Results of this study indicate that AMF surround the rhizosphere of Inga seedlings in relatively low proportions compared to other fungal groups but present in both terra firme and várzea Neotropical ecosystems.

Non-native plants and soil microbes: potential contributors to the consistent reduction in soil aggregate stability caused by the disturbance of North American grasslands.

• Soil aggregate stability is an important ecosystem property that is altered by anthropogenic disturbance. Yet, the generalization of these alterations and the identification of the main contributors are limited by the absence of cross-site comparisons and the application of inconsistent methodologies across regions. • We assessed aggregate stability in paired remnant and post-disturbance grasslands across California, shortgrass and tallgrass prairies, and in manipulative experiments of plant composition and soil microbial inoculation. • Grasslands recovering from anthropogenic disturbance consistently had lower aggregate stability than remnants. Across all grasslands, non-native plant diversity was significantly associated with reduced soil aggregate stability. A negative effect of non-native plants on aggregate stability was also observed in a mesocosm experiment comparing native and non-native plants from California grasslands. Moreover, an inoculation study demonstrated that the degradation of the microbial community also contributes to the decline in soil aggregate stability in disturbed grasslands. • Anthropogenic disturbance consistently reduced water-stable aggregates. The stability of aggregates was reduced by non-native plants and the degradation of the native soil microbial community. This latter effect might contribute to the sustained decline in aggregate stability following anthropogenic disturbance. Further exploration is advocated to understand the generality of these potential mechanisms.

What are mycorrhizal traits?

Traits are inherent properties of organisms, but how are they defined for organismal networks such as mycorrhizal symbioses? Mycorrhizal symbioses are complex and diverse belowground symbioses between plants and fungi that have proved challenging to fit into a unified and coherent trait framework. We propose an inclusive mycorrhizal trait framework that classifies traits as morphological, physiological, and phenological features that have functional implications for the symbiosis. We further classify mycorrhizal traits by location - plant, fungus, or the symbiosis - which highlights new questions in trait-based mycorrhizal ecology designed to charge and challenge the scientific community. This new framework is an opportunity for researchers to interrogate their data to identify novel insights and gaps in our understanding of mycorrhizal symbioses.

Symbionts as Filters of Plant Colonization of Islands: Tests of Expected Patterns and Environmental Consequences in the Galapagos.

The establishments of new organisms that arrive naturally or with anthropogenic assistance depend primarily on local conditions, including biotic interactions. We hypothesized that plants that rely on fungal symbionts are less likely to successfully colonize remote environments such as oceanic islands, and this can shape subsequent island ecology. We analyzed the mycorrhizal status of Santa Cruz Island, Galapagos flora compared with the mainland Ecuador flora of origin. We experimentally determined plant responsiveness and plant-soil feedback of the island flora and assessed mycorrhizal density and soil aggregate stability of island sites. We found that a greater proportion of the native island flora species belongs to families that typically do not associate with mycorrhizal fungi than expected based upon the mainland flora of origin and the naturalized flora of the island. Native plants benefited significantly less from soil fungi and had weaker negative soil feedbacks than introduced species. This is consistent with the observation that field sites dominated by native plant species had lower arbuscular mycorrhizal (AM) fungal density and lower soil aggregate stability than invaded field sites at the island. We found support for a mycorrhizal filter to the initial colonization of the Galapagos.

Mycorrhizal fungi influence global plant biogeography.

Island biogeography has traditionally focused primarily on abiotic drivers of colonization, extinction and speciation. However, establishment on islands could also be limited by biotic drivers, such as the absence of symbionts. Most plants, for example, form symbioses with mycorrhizal fungi, whose limited dispersal to islands could act as a colonization filter for plants. We tested this hypothesis using global-scale analyses of ~1.4 million plant occurrences, including ~200,000 plant species across ~1,100 regions. We find evidence for a mycorrhizal filter (that is, the filtering out of mycorrhizal plants on islands), with mycorrhizal associations less common among native island plants than native mainland plants. Furthermore, the proportion of native mycorrhizal plants in island floras decreased with isolation, possibly as a consequence of a decline in symbiont establishment. We also show that mycorrhizal plants contribute disproportionately to the classic latitudinal gradient of plant species diversity, with the proportion of mycorrhizal plants being highest near the equator and decreasing towards the poles. Anthropogenic pressure and land use alter these plant biogeographical patterns. Naturalized floras show a greater proportion of mycorrhizal plant species on islands than in mainland regions, as expected from the anthropogenic co-introduction of plants with their symbionts to islands and anthropogenic disturbance of symbionts in mainland regions. We identify the mycorrhizal association as an overlooked driver of global plant biogeographical patterns with implications for contemporary island biogeography and our understanding of plant invasions.

MycoDB, a global database of plant response to mycorrhizal fungi.

Plants form belowground associations with mycorrhizal fungi in one of the most common symbioses on Earth. However, few large-scale generalizations exist for the structure and function of mycorrhizal symbioses, as the nature of this relationship varies from mutualistic to parasitic and is largely context-dependent. We announce the public release of MycoDB, a database of 4,010 studies (from 438 unique publications) to aid in multi-factor meta-analyses elucidating the ecological and evolutionary context in which mycorrhizal fungi alter plant productivity. Over 10 years with nearly 80 collaborators, we compiled data on the response of plant biomass to mycorrhizal fungal inoculation, including meta-analysis metrics and 24 additional explanatory variables that describe the biotic and abiotic context of each study. We also include phylogenetic trees for all plants and fungi in the database. To our knowledge, MycoDB is the largest ecological meta-analysis database. We aim to share these data to highlight significant gaps in mycorrhizal research and encourage synthesis to explore the ecological and evolutionary generalities that govern mycorrhizal functioning in ecosystems.

ESTIMULACIÓN DE GERMINACIÓN Y COLONIZACIÓN RADICULAR DE Diversispora trimulares POR FLAVONOIDES DE EXUDADOS RADICULARES DE Nicotiana glauca / STIMULATION OF GERMINATION OF SPORES AND ROOT COLONIZATION OF Diversispora trimulares BY FLAVONOIDS IN Nicotiana glauca ROOT EXUDATES

Los metabolitos secundarios son señales importantes en la interacción planta-microrganismos; sin embargo, los datos que corroboran el rol de los flavonoides como señales entre plantas y la simbiosis micorrízica arbuscular son limitados y aún recientes. Este estudio tiene por objetivo evaluar el efecto de flavonoides presentes en exudados radiculares de Allium porrum L., Nicotiana gluaca y Brassica oleracea var. Itálica, en la germinación de esporas y establecimiento de colonización radicular de Diversispora trimulares. Se detectaron miricetina y canferol en exudados de A. porrum, con un contenido total de flavonoides de 23,80µg g-1, de raíz seca; quercetina, en N. glauca, con 23,35µg g-1 y crisina, en B. oleracea, con 14,71µg g-1. Quercetina estimuló la germinación y la vitalidad de esporas (24%, 40%), a diferencia de crisina, que presentó un efecto inhibitorio (4%, 20%). A. porrum y N. glauca incrementaron la germinación de esporas (54%, 56%) y porcentaje de colonización de micorriza arbuscular (72%, 75%). Los resultados de la investigación mostraron una evidencia sólida del efecto de los flavonoides como moléculas estimulantes en los procesos de germinación de esporas y colonización de micorriza arbuscular.

Secondary metabolites are important signals that could determine the outcome of the plant soil microbial interactions, however, the data available that support the leading role of flavonoids in the communication of arbuscular mycorrhizal symbiosis are recent and limited. The present study examines the effect of flavonoids detected in root exudates from Allium porrum, Nicotiana glauca y Brassica oleracea var. italica on spore germination and mycorrhizal root colonization of Diversispora trimulares. Myricetin and kaempferol were detected in A. porrum root exudates with a total flavonoid content of 23.80µg g-1 dried root, quercetin in N. glauca with 23,35µg g-1 and chrysin in B. Oleracea with 14.71 µg g-1. Quercetin increased the spore germination and vitality (24%, 40%). In contrast, chrysin showed an inhibitory effect (4%, 20%). A. porrum and N. glauca increased spore germination (54%, 56%) and root mycorrhizal colonization (72%, 75%). This results evidence the effect of flavonoids on the stimulization of spore germination and stablishment of root colonization of arbuscular mycorrhizal fungi.