Mycorrhizal Associations Research Articles

Mycorrhizal specialization toward each distinct Oliveonia fungus in two closely related photosynthetic Dactylostalix orchids

Abstract Although rhizoctonias from Ceratobasidiaceae, Tulasnellaceae and Serendipitaceae are typical orchid mycobionts, orchid mycorrhizal fungi exhibit vast taxonomic and ecological diversity. This diversity stems from the high specificity of orchid mycorrhizal associations and the remarkable diversity of over 28,000 orchid species. The subtribe Calypsoinae is particularly notable for its diverse mycorrhizal partnerships, including rhizoctonias, ectomycorrhizal and saprotrophic non‐rhizoctonia fungi. However, the mycobionts within certain Calypsoinae lineages, such as the genus Dactylostalix, remain understudied. This study explores the physiological ecology of two photosynthetic Calypsoinae species, Dactylostalix ringens and Dactylostalix uniflora, to gain insight into potentially novel associations and their ecological implications. We analysed the mycorrhizal communities of both Dactylostalix species using high‐throughput ITS metabarcoding of root samples collected from multiple locations. Additionally, we measured the natural abundances of 13C and 15N isotopes in the leaves of the two Dactylostalix species and their co‐occurring autotrophic reference plants, as well as in fungal pelotons isolated from D. ringens, to assess the potential for partial mycoheterotrophy. Our findings revealed that D. ringens and D. uniflora form specialized mycorrhizal associations predominantly with distinct lineages of Oliveonia (Oliveoniaceae, Auriculariales), even in sympatric populations. Stable isotope analysis showed that both Dactylostalix species exhibited conflicting isotopic signals: elevated δ15N values, supporting partial mycoheterotrophy, but lower δ13C values compared to autotrophic plants, suggesting autotrophy. Peloton samples from D. ringens displayed only modest 13C enrichment relative to autotrophic references. These conflicting isotopic signals make it difficult to precisely determine whether both Dactylostalix species are autotrophic or partially mycoheterotrophic. Intriguingly, the 13C and 15N signatures of Dactylostalix species and their pelotons resemble those of many rhizoctonia‐associated orchids. This isotopic evidence implies a niche overlap with endophytic tendencies between rhizoctonias and Oliveonia, suggesting that potential endophytic traits may have facilitated the recruitment of Oliveonia as novel mycorrhizal partners. Furthermore, the mycorrhizal segregation between D. ringens and D. uniflora likely promotes their sympatric coexistence and may contribute to reproductive isolation through ecological specialization. Read the free Plain Language Summary for this article on the Journal blog.

Enhancing cold tolerance in tobacco through endophytic symbiosis with Piriformospora indica

Tobacco, a warm-season crop originating from the Americas, is highly susceptible to cold stress. The utilization of symbiotic fungi as a means to bolster crops’ resilience against abiotic stresses has been proven to be a potent strategy. In this study, we investigated the effect of endophytic fungus Piriformospora indica on the cold resistance of tobacco. When exposed to cold stress, the colonization of P.indica in tobacco roots effectively stimulates the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). This, in turn, reduces the accumulation of reactive oxygen species (ROS), thereby mitigating oxidative damage. Additionally, P. indica elevates the levels of osmolytes, such as soluble sugars, proline, and soluble proteins, thus facilitating the restoration of osmotic balance. Under cold stress conditions, P. indica also induces the expression of cold-responsive genes. Furthermore, this fungus not only enhances photosynthesis in tobacco by stimulating the synthesis of photosynthetic pigments, strengthening Rubisco activity, and elevating PSII efficiency, but also fortifies tobacco’s nitrogen assimilation by inducing the expression of nitrate transporter gene and activating enzymes related to nitrogen assimilation. Consequently, this synergistic optimization of nitrogen and carbon assimilation provides a solid material and energetic foundation for tobacco plants to withstand cold stress. Our study demonstrates that a mycorrhizal association between P. indica and tobacco seedlings provides multifaceted protection to tobacco plants against low-temperature stress and offers a valuable insight into how P. indica enhances the cold tolerance of tobacco.

Variations in the root mycobiome and mycorrhizal fungi between different types of Vanilla forest farms on Réunion Island.

The mycorrhizal fungi of cultivated Vanilla spp. have mainly been studied in America, while a recent study has investigated them on Réunion Island (Indian Ocean). However, there are many different types of cultivation on Réunion, from shade-house crops to forest farms of endemic or exotic trees. Here we fill a gap in the study of the root mycobiome of Vanilla by sampling vines in forest plantations on recent lava flows in the southeast of Réunion. Specifically, we aimed to characterize the fungal communities between terrestrial and epiphytic roots, between forest farms that differ mainly in the species of trees, and between Vanilla roots and ECM-like roots of nearby trees. By sequencing fungal ITS2, we showed that the Vanilla root mycobiome is diverse and differed between the root types and forest farms. Epiphytic and terrestrial roots host endophytic fungi, while a putative rust with visible urediniospores was abundant in terrestrial roots mainly. Other pathogens were detected in epiphytic roots (Colletotrichum) with no sign of disease. Following sequencing and electron microscopy, Tulasnellaceae, characterized by imperforate parenthesomes and cell wall expansion with an amorphous matrix, were shown to be the main mycorrhizal fungi in both vanilla root types. Interestingly, the dominant Tulasnellaceae OTU was found in ECM-type roots of trees belonging to the ectomycorrhizal family Sapotaceae. Further observations are needed to confirm the ectomycorrhizal association of endemic trees with Tulasnella. Moreover, labeling experiments will be instrumental in investigating the transfer of nutrients between the trees and the Vanilla through the network of mycorrhizal associations in the soil.

Associations of Arbuscular Mycorrhizal Fungi (AMF) for Enhancements in Soil Fertility and Promotion of Plant Growth: A Review

Arbuscular Mycorrhizal Fungi are used for soil fertility enhancements and stimulating plant growth in which they association with other organisms like terrestrial plants. Mycorrhizas create an association between fungi and the roots of plants. Therefore, the review was made to point out important fungal species involved in fungal plant interaction and their major roles in agriculture as well as ecosystem. 80% of plants form associations with mycorrhizal fungi. The fungal are used to use their different organs like chain, arbuscular, vesicle, supportive cells and spore to interact with the other plant/ plat’s organ. The mycorrhizal fungi can be categorized into two principal classifications based on their anatomical interactions with the roots of host plants. Arbuscular Mycorrhizal and Ectomycorrhizal fungi utilize two distinct strategies for nutrient acquisition. The main categories of vesicular arbuscular mycorrhizal associations are linear or coiling and of ectomycorrhizal associations are epidermal or cortical. The rhizospheric and endophytic microbes promote plant growth as inoculated with crop. AM fungi as an obligate symbiont share a distinct feature called arbuscules as a site of nutrient exchanges between host and fungi. Arbuscules developed between cell wall and plasma membrane of root cortical cells and differentiated from plant plasma membrane by periarbuscular membrane. Arbuscular mycorrhizal fungi (AMF) play an indispensable role in augmenting plant nutrient acquisition, enhancing plant resilience and tolerance to various environmental stresses, improving soil fertility and structure, and providing numerous beneficial effects. AMF engage in interactions with other soil microorganisms, such as plant growth-promoting rhizobacteria, resulting in a synergistic effect that promotes plant growth and offers protection against pathogens associated with Rhizobia. Both AMF and Rhizobia utilize the same signaling pathways, which facilitate their association with host plants and enable nitrogen fixation within the soil ecosystem. A positive relationship has been established between AMF colonization and the diversity of soil microbial communities. Nitrogen-fixing rhizobia, mycorrhizal fungi, and root nodule symbioses typically exhibit synergistic interactions concerning infection rates and their effects on mineral nutrition and plant growth, thereby significantly enhancing the status of soil fertility, particularly with respect to soil quality characteristics.

Diversity of Mycorrhizal Types Along Altitudinal Gradients in the Tropical Andes

ABSTRACTAimMycorrhizal fungi play key roles in the functioning of terrestrial ecosystems. The main types of mycorrhizal associations are arbuscular mycorrhizae, ectomycorrhizae, ericoid mycorrhizae and orchid mycorrhizae. Previous studies have shown that the abundance of plants with different types of mycorrhizal associations change gradually along latitudinal and altitudinal gradients driven by the effects of climate and soil nutrients. We aimed to understand how altitude and climatic and soil variables shape the distribution patterns of tropical plant mycorrhizal types and nitrogen‐fixing plants along altitudinal gradients in the Andes.LocationColombian Andean mountain range.Time PeriodPresent day.Major Taxa StudiedPlants (vascular and non‐vascular).MethodsWe used a herbarium plant records database and assigned mycorrhizal type to each plant species based on the available literature. Bioclimatic and soil variables were also compiled at a resolution of 10 km. We calculated the proportion of each mycorrhizal association type per grid cell and created a diversity index to explore their spatial distribution and association with abiotic factors based on LMs.ResultsThe diversity of mycorrhizal associations increased with altitude and peaked around 3000 m, in an ecotone belt known as the subpáramo recognised by the high abundance of Ericaceae species. Soil carbon stock and soil total nitrogen were also positively correlated with the diversity of mycorrhizal types. Moreover, the abundance of arbuscular mycorrhizal plants was highest at low elevations and increased with the proportion of nitrogen‐fixing plants per cell.Main ConclusionsOur results indicate that mycorrhizal associations gradually change along altitudinal gradients in the tropical Andes. Climatic factors and the interactions between climatic and edaphic factors have the greatest explanatory power to predict the distribution of types of mycorrhizal associations along the altitudinal gradient. Based on these results we expect that climate change could potentially alter the distribution of mycorrhizal types in tropical mountains with unknown consequences for ecosystem functions.

Transcriptomic insights into mycorrhizal interactions with tomato root: a comparative study of short- and long-term post-inoculation responses.

Arbuscular mycorrhiza (AM) refers to a symbiotic association between plant roots and fungi that enhances the uptake of mineral nutrients from the soil and enables the plant to tolerate abiotic and biotic stresses. Although previously reported RNA-seq analyses have identified large numbers of AM-responsive genes in model plants, such as Solanum lycopersicum L., further studies are underway to comprehensively understand the complex interactions between plant roots and AM, especially in terms of the short- and long-term responses after inoculation. Herein, we used RNA-seq technology to obtain the transcriptomes of tomato roots inoculated with the fungus Rhizophagus irregularis at 7 and 30days post inoculation (dpi). Of the 1,019 differentially expressed genes (DEGs) in tomato roots, 635 genes showed differential expressions between mycorrhizal and non-mycorrhizal associations at the two time points. The number of upregulated DEGs far exceeded the number of downregulated ones at 7 dpi, and this difference decreased at 30dpi. Several notable genes were particularly involved in the plant defense, plant growth and development, ion transport, and biological processes, namely, GABAT, AGP, POD, NQO1, MT4, MTA, and AROGP3. In addition, the Kyoto encyclopedia of genes and genomes pathway enrichment analysis revealed that some of the genes were involved in different pathways, including those of ascorbic acid (AFRR, GME1, and APX), metabolism (CYP, GAPC2, and CAM2), and sterols (CYC1 and HMGR), as well as genes related to cell division and cell cycle (CDKB2 and PCNA). These findings provide valuable new data on AM-responsive genes in tomato roots at both short- and long-term postinoculation stages, enabling the deciphering of biological interactions between tomato roots and symbiotic fungi.

Reclaiming Calcicoles: New Insights into Lime Lovers

Calcicoles are never new to the evolutionary life forms in the ecological world. The ramifications of environmental extremes always facilitate the emergence of the functional and structural integrity of plants and calcicoles, which have been exuding through this. The word “calcicole” finds its roots in the writings of Nathaniel Colgan, “The Orchids of Country Dublin,” published in August 1895 in “The Irish Naturalist.” Calcicoles are likely to flourish under calcium-rich soil having a pH of more than five, which otherwise hinders the growth of plant species, causing detrimental effects on their physiology. They are often regarded as lime lovers or acidofuges and are classified based on Ca2+ stress resistance, soluble and insoluble Ca2+ and Mg2+, pH conditions of soil, occurrence, and habitat. There are various variables used to evaluate the calcicoles described in this review, such as the Index of calcifugy, Ellenberg’s indicator values, and Landolt indicator values to predict the influence of environmental factors in determining flora along with changes in vegetation in a particular area considering the ecophysiological or morphological features. Calcicoles have specific in-built mechanisms to cope with stress conditions by producing phytosiderophores (PS) and by involving ecto and ericoid mycorrhizal associations for the absorption of iron and phosphorus, and high control over cytosolic Ca2+ concentrations. Calcicoles are markedly distributed in various plant families like Asteraceae, Brassicaceae, Amaranthaceae, Caryophyllaceae, Ericaceae, Primulaceae, Fabaceae, Gentianaceae, Rubiaceae, Plantaginaceae, Poaceae, Saxifragaceae, etc. The current review focuses on the ecological perspectives, special adaptive features, and phytopharmacological aspects of calcicoles.

Mycorrhizal Associations in Orchids: A Review

Mycorrhizal Associations in Orchids: A Review

A mycoheterotrophic orchid uses very limited soil inorganic nitrogen in its natural habitat

Mycoheterotrophic plants acquire nitrogen (N) directly from the soil and through their symbiotic fungi. The fungi-derived N has received considerable attention, but the contribution of soil-derived N has been largely overlooked. We investigated how the leafless, rootless, and almost mycoheterotrophic orchid Cymbidium macrorhizon obtains soil N by applying 15N-labeled ammonium nitrate in its natural habitat, and tracking metabolite accumulation and mycorrhizal fungal association after N application. The decline of N in the rhizome from flowering to fruiting indicated a transfer of N from the rhizome to fruits. At current dose of N application (0.6 g NH4NO3 each plant), only 1.5% of the plant's N was derived from fertilizer, resulting in a low nitrogen use efficiency of 0.27%. The majority of those newly absorbed N (88.89%) was found sank in the rhizome. Amino acids (or their derivatives) and alkaloids were predominant differentially accumulated nitrogenous metabolites after N application, with amino acids occurring in both fruits and the rhizome, and alkaloids primarily in the fruits. The addition of N did not alter the richness of mycorrhizal fungi, but did affect their relative abundance. Our findings suggest that Cymbidium macrorhizon uses very limited soil inorganic nitrogen in its natural habitat, and the root-like rhizome primarily stores N rather than absorbs its inorganic forms, offering new insights into how mycoheterotrophic plants utilize soil N, and the influence of nutrient availability on the orchid-fungi association.

Impact of arbuscular mycorrhizal fungi on maize rhizosphere microbiome stability under moderate drought conditions.

With an alarming increase in global greenhouse gas emissions, unstable weather conditions are significantly impacting agricultural production. Drought stress is one of the frequent consequences of climate change that affects crop growth and yield. Addressing this issue is critical to ensure stable crop productivity under drought conditions. Arbuscular mycorrhizal fungi (AMF) establish symbiotic relationships with plants and enhance their resistance to adverse conditions. Effects of arbuscular mycorrhizal associations on the rhizosphere microbiome and root transcriptome under drought conditions have not been explored. Here, we investigated the effects of AMF and drought stress on rhizosphere microorganisms and root transcriptome of maize plants grown in chernozem soil. We used high-throughput sequencing data of bacterial 16S rRNA and fungal internal transcribed spacer regions (ITS) to identify rhizosphere microorganisms. Transcriptomic data were used to assess gene expression in maize plants under different treatments. Our results show that AMF maintains the composition of maize rhizosphere microorganisms under drought stress. In particular, the bacterial and fungal phyla maintained were Actinomycetes and Ascomycota, respectively. Transcriptomic data indicated that AMF influenced gene expression in maize plants under drought stress. Under drought stress, the expression of SWEET13, CHIT3, and RPL23A was significantly higher in the presence of AMF than it was without AMF inoculation, indicating better sugar transport, reduced malondialdehyde accumulation, and improved water use efficiency in AMF-inoculated maize plants. These findings suggest that AMF can enhance the resistance of maize to moderate drought stress by stabilising plant physical traits, which may help maintain the structure of the rhizosphere microbial community. This study provides valuable theoretical insights that should aid the utilization of AMF in sustainable agricultural practices.

Hongos micorrícicos arbusculares y endófitos septados oscuros en raíces de helechos nativos de uso medicinal de las Sierras Centrales de San Luis, centro-oeste de Argentina

Background and aims: The plant´s roots and fungi establish symbiotic endophytic associations that can coexist: arbuscular mycorrhizae and “dark septate” endophytes. Ferns and lycophytes are vascular plants that can form both fungal symbioses. The objective of this work is to detect the presence of fungal root endosymbiosis, know the mycorrhizal status, and analyze the type of colonizationin in native and ornamental ferns from the “Sierras Centrales de San Luis”. M&M: In three sites in the “Sierras Centrales de San Luis”, 9-10 individuals of each studied species were collected, their roots were processed to study these fungal. Characterization and quantification of their root colonization was evaluated. Results: In the three sites studied, Anemia tomentosa var. anthriscifolia formed mycorrhizal associations, the colonization presented abundant hyphal and arbusculated intracellular coils. In addition, glomoid spores of mycorrhizal fungi were found in their rhizospheres. Dark septate endophytes were absent in all species analyzed, none hyphae neither microsclerotia were recorded in roots of these native medicinal ferns. Conclusions: The mycorrhizal status of Anemia tomentosa var. anthriscifolia, one of the five medicinal fern species from the Sierras Centrales de San Luis studied, is presented. The arbuscular mycorrhizal colonization is described and quantified, and its type is determined as Paris. None of the fern species studied was associated with dark septate endophytes.

Revisiting biochemical pathways for lead and cadmium tolerance by domain bacteria, eukarya, and their joint action in bioremediation.

With the advent rise is in urbanization and industrialization, heavy metals (HMs) such as lead (Pb) and cadmium (Cd) contamination have increased considerably. It is among the most recalcitrant pollutants majorly affecting the biotic and abiotic components of the ecosystem like human well-being, animals, soil health, crop productivity, and diversity of prokaryotes (bacteria) and eukaryotes (plants, fungi, and algae). At higher concentrations, these metals are toxic for their growth and pose a significant environmental threat, necessitating innovative and sustainable remediation strategies. Bacteria exhibit diverse mechanisms to cope with HM exposure, including biosorption, chelation, and efflux mechanism, while fungi contribute through mycorrhizal associations and hyphal networks. Algae, especially microalgae, demonstrate effective biosorption and bioaccumulation capacities. Plants, as phytoremediators, hyperaccumulate metals, providing a nature-based approach for soil reclamation. Integration of these biological agents in combination presents opportunities for enhanced remediation efficiency. This comprehensive review aims to provide insights into joint action of prokaryotic and eukaryotic interactions in the management of HM stress in the environment.

Enhanced fig tree production through endomycorrhizal fungi inoculation: A nursery study on tree cuttings derived from the Ifrane Region, Morocco

The mycorrhizal association represents a crucial symbiotic bond necessary for the vitality of the majority of plants. This report aims to investigate the impact of endomycorrhizal fungi on the production of fig trees from cuttings. The research took place in a nursery environment by inoculating fig cuttings sourced from three sites in Morocco with a composite inoculum of arbuscular mycorrhizal fungi (AMF). The mean root and vegetative masses of the inoculated plants after 140 days were 33.1 g and 35 g compared with 1.8 g and 6.4 g in the control. The mean shoot length and number of leaves developed from treated cutting were 98.5 cm and 17, respectively 29 cm and 4 leaves in control. Thus, the newly formed roots showed a well-established mycorrhizal colonization and contained different structures characteristic of arbuscular endomycorrhizae: arbuscules, vesicles, endophytes, hyphae and spores. The frequency and intensity of root mycorrhization were approximately 80% and 15.5%, respectively. The contents of arbuscules and vesicles were 2.5% and 5.5%. The study of formed spores showed a combination of 52 spores per 100 g of soil, belonging to 11 species and 3 genera: Glomus, Acaulospora and Rhizophagus with dominance of the genus Glomus (85%). Glomus macrocarpum and Glomus deserticola were the most abundant species, appearing at 30.77% and 19.23%, respectively. The results demonstrate a pronounced stimulating effect on both root formation and vegetative shoot development in the inoculated cuttings. Specifically, the early inoculation of fig cutting with the AMF inoculum significantly enhanced rhizogenesis end root system development. Consequently, the gradual establishment of mycorrhizal symbiosis at the root level of inoculated plants led to good development of the root mass and the vegetative mass. The inoculated plants showed good root and vegetative mass development due to the installation and the progressive development of mycorrhizal symbiosis at their roots.

Bilberry Expansion in the Changing Subalpine Belt.

Bilberry (Vaccinium myrtillus L.) expansion in subalpine and alpine ecosystems is increasing due to climate change and reduced land management. This review examines bilberry traits, environmental responses, and ecosystem impacts. As a stress-tolerant chamaephyte, bilberry thrives in acidic, nutrient-poor soils across various habitats. It propagates effectively through rhizomes and demonstrates a phalanx growth form. Bilberry's growth and distribution are influenced by elevation, soil structure, pH, water availability, and nitrogen content. Mycorrhizal associations play a crucial role in nutrient uptake. The species modifies the microclimate, facilitates litter accumulation, and influences soil microbial communities, affecting nutrient turnover and biodiversity. Bilberry shows moderate tolerance to herbivory and frost, with the ability to recover through rapid emergence of new ramets. However, severe or repeated disturbances can significantly impact its abundance and reproductive success. Climate warming and atmospheric nitrogen deposition have accelerated bilberry growth in treeline ecotones. The management of bilberry expansion requires a nuanced approach, considering its resilience, historical land-use changes, and environmental factors. The goal should be to limit, not eliminate, bilberry, as it is a natural part of subalpine communities. Long-term comparative monitoring and experimental manipulation are necessary for effective management strategies.

Ecology of arbuscular mycorrhizal association in coconut (Cocos nucifera L.) palms: Analysis of factors influencing AMF in fields

This study is the first thorough ecological analysis of arbuscular mycorrhizal fungal (AMF) diversity in randomly selected traditional coconut fields across Kerala, South India. We conducted a critical analysis of AMF diversity, percentage root length colonization (PRLC), and mean spore density (MSD) across 248 sites, taking into account variations in plant, environmental, and soil factors like coconut varieties, palm health conditions, agroclimatic zones, soil types, and seasons in the region. A total of 23 AMF species from seven genera (Acaulospora, Archaeospora, Funneliformis, Glomus, Sclerocystis, Septoglomus, and Scutellospora) were identified, with Acaulospora scrobiculata being the dominant species in all studied fields. A critical analysis of diversity indices, including the Shannon-Weiner Index, Simpson's diversity index, and Gini-Simpson index, concerning variables indicated that soil series influences AMF diversity in specific fields. Correlational and principal component analyses highlighted the interrelationships between specific soil types and quality parameters affecting AMF characteristics, underscoring their crucial role in coconut palm growth. The study also revealed the ecological amplitudes of indigenous AMF species related to specific soil fertility parameters. Overall, this research serves as a model for identifying root- and soil-specific AMF in agricultural fields and provides valuable ecological insights for utilizing indigenous AMF species as ecotechnological tools for sustainable coconut cultivation.

Silvicultural Management Impact on Soil Mycorrhizal Association in Tigray Parklands Agroforestry Practices

Silvicultural Management Impact on Soil Mycorrhizal Association in Tigray Parklands Agroforestry Practices

‘There must be something in the soil our little plants need’: exploring patterns of potential mycorrhizal associations in the flora of the Sunshine Coast heathlands, Queensland, Australia

The first general overview of mycorrhizal functional groups associated with the flora of the Queensland Sunshine Coast heathlands, a community of low phylogenetic diversity, is provided in this Short Communication. Broad proportions of plant species associated with mycorrhizal and non-mycorrhizal functional groups in the heathlands were compared with those in the surrounding rainforest flora, and across the heath strata. This overview suggests that a greater diversity of mycorrhizal strategies and an increased number of plant genera with non-mycorrhizal associations are found in the heathlands, with proportions varying among the strata. These associations may be facilitating the coexistence of plant species and increasing phylogenetic dispersion.

1117. Crepidiastrum grandicollum (Koidz.) Nakai: Compositae: Plants in peril 41

SummaryCrepidiastrum grandicollum (Koidz.) Nakai (Compositae: Lactuceae: Crepidinae) is described and illustrated. The current synonymy is provided, together with type citations for each of the names and statements of the type material. A selection of verified illustrations of the species in the literature is provided. Statements of the species' distribution, habitat and ecological preferences (with observations on the phytosociological classification), phenology, conservation status, and the etymology of both generic and specific epithets are given along with vernacular names, some of which are apparently literal translations of the Latin binomial. Cultivation, propagation, and availability notes are provided, although the species is Critically Endangered and currently only cultivated Koishikawa Botanical Garden, University of Tokyo, Japan, as part of the Ministry of the Environment's Rare Wild Fauna and Flora Species Protection and Breeding Project. Discussions include pollination syndromes in Crepidiastrum in the Bonin Islands, the intricacies of the involvement of the Honey Bee in their pollination (compared with conservation measures) and the displacement of native insect pollinators, mention of seed/achene dispersal and evolution within the genus, conservation proposals, including the use of exclosures to prevent destruction by feral goats (Capra hircus), and electric fences, adhesive traps and Teflon™ sheets to help control the lizard known as the Green Anole (Anolis carolinensis); typhoon damage and the potential for issues with ants ‐ Pheidole (Westwood) spp. (including the African Big‐headed Ant, P. megacephala) are also mentioned. Some consideration for the rôle of Arbuscular Mycorrhizal (AM) associations with the endemics in conservation programmes should not be overlooked. Attention is drawn to observations on some bizarre web sites with somewhat bogus information on the species, and why they should be disregarded.

The root strategy of the C4 grasses tends to be ‘do-it-yourself’

Root resource acquisition strategies play a crucial role in understanding plant water uptake and drought adaptation. However, the interrelationships among mycorrhizal associations, root hair development, and fine root strategies, as well as the disparities between C3 and C4 grasses, remain largely unknown. A pot experiment was conducted to determine leaf gas exchange, root morphology, root hair, mycorrhizal fungi, and biomass allocation of three C4 grasses and four C3 grasses, common species of grasslands in Northeast China, under the control and drought conditions. Compared to the C3 grasses, the C4 grasses increased specific surface area by decreasing tissue density, yet exhibited root hair factor at only 21 % of the C3 grasses. Under the drought conditions, the C4 grasses exhibited more intense and extensive adjustments in root traits, characterized by shifts toward a more conservative morphology with increased root diameter and tissue density, as well as reduced mycorrhizal colonization rates. These adaptations led to a decrease in root absorptive function, which was compensated in the C4 grasses by greater root biomass partitioning and root hair factor. Variances in root strategies between plants functional groups were closely related to leaf photosynthetic rate, water and nitrogen use efficiency. We observed that the C4 grasses prefer direct acquisition of soil resources through the fine root pathway over the root hair or mycorrhizal pathway, suggesting a ‘do-it-yourself’ approach. These findings provide valuable insights into how plant communities of different photosynthetic types might respond to future climate change.

The interactive effect of tree mycorrhizal type, mycorrhizal type mixture and tree diversity shapes rooting zone soil fungal communities in temperate forest ecosystems

Abstract The underlying processes of plant‐microbe associations particularly their interactions with their mycorrhizal fungal partners have been extensively studied. However, considerably less is known about the consequences of tree‐tree interactions on rooting zone soil microbiota when tree species of different mycorrhizal type (myco‐type) grow together as mono and mixed myco‐type mixtures along a tree diversity gradient. Using the MyDiv tree diversity experiment, where arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) trees and their mixtures were planted in monocultures, two‐species and four‐species mixture plots, we investigated the interplay of target tree myco‐type, myco‐type mixture, tree diversity and rooting zone compartment (target tree dominated and its interaction zones with neighbour trees) on the rooting zone soil mycobiota employing meta‐barcoding of the ITS2 rDNA fragment of the fungal internal transcribed spacer (ITS). Our results revealed significant individual and interaction effects of tree myco‐type, myco‐type mixture and tree diversity but not rooting zone compartment on the fungal taxonomic and functional alpha and beta diversity. This implies intermingling of roots of target and neighbouring tree species there by reducing the target tree species effect in its rooting zone. As tree diversity increases, we found convergence of the fungal community in general, where the fungal community dissimilarity varies depending on the co‐existing tree species myco‐type and tree species diversity. Furthermore, the fungal community composition in the two and four species mixtures were consistently influenced by soil pH, whereas in the mixed multi‐species stands basal respiration, N, PO4−, NO3− were found to be equally important unlike in AM and EcM multi‐species stands. Comparative analysis of the fungal taxa specialisation between mono and mixed myco‐type multi‐species stands revealed that the mixed myco‐type plots shared 23.5% (AM) and 19.7% (EcM) of the generalist fungal communities However, the percentage of specialised fungal community in mixed myco‐type plots (13.2%) was significantly higher as compared to EcM (9.5%), and significantly lower (9%) as compared to AM (11.7%) plots, resulting in myco‐type and myco‐type mixture specific fungal communities and functional guild patterns Our results provide novel insights on the significance of tree species and its co‐existing trees preferred mycorrhizal association in shaping the target tree rooting zone soil mycobiome along a tree diversity gradient. Furthermore, it highlights the significance of generalist and specialist fungal communities in mono and mixed myco‐type stands in modulating tree‐tree interaction, tree species co‐existence and regulating soil properties and ecosystem functions. Read the free Plain Language Summary for this article on the Journal blog.