Micronutrient transport in mycorrhizal symbiosis; zinc steals the show

Arbuscular Mycorrhizal Fungi Improve Rice Production in Zinc-Amended Soils by Altering Zinc Transport and Translocation Routes

Human activities including industry and overcultivation resulted in marginal soils, unbalanced in nutrients or polluted with heavy metals. Zinc (Zn) is an essential micronutrient and its nonoptimal soil bio-availability, negatively affects plant growth and production. Arbuscular mycorrhizal fungi (AMF) could improve Zn acquisition in limited conditions and prevent accumulation in plant tissue in contaminated soils. However, it is not clear how AMF impact host plant Zn uptake and transport routes. In this study we assessed the potential of commercial AMF inoculum to support rice growth and production in non-Zn-fertilised, Zn-fertilised and Zn-polluted soils alongside their impact on host plant nutrient balances and Zn uptake and translocation routes. The results demonstrated that AMF inoculation restores rice growth and grain production in Zn-amended soils and that Zn amendment improves root colonisation. Shoot ionomes were particularly sensitive to differences in Zn supply and differentially affected in AMF and mock-inoculated plants. When present in excess, AMF inoculation decreased accumulation of Zn in shoots and disturbed Zn-P (phosphorus) relationship. We could not detect a mycorrhiza-specific Zn transporter in rice but rather a modification of expression for Zn transporters in the direct uptake routes. AMF inoculation interacts with the Zn-dependent response of heavy metal ATPase (OsHMA) transporters involved in root-to-shoot translocation. All together, these data indicate a change in relative importance of different direct Zn transport routes upon AMF colonisation. These findings provide valuable insights into how AMF symbiosis influences Zn uptake and distribution in rice under varying Zn conditions, allowing for the development of plant-fungus bioremediation and biofortification technologies.

The Rhizophagus irregularis permease RiFTR1 functions without a ferroxidase partner for reductive iron transport

The contribution of arbuscular mycorrhizal fungi (AM fungi) to plant iron (Fe) acquisition has been demonstrated in several studies. A previous investigation revealed that the AM fungus Rhizophagus irregularis utilizes a high-affinity reductive pathway for Fe uptake, mediated by the Fe transporter RiFTR1. In this study, we used a genome-wide approach in R. irregularis to find genes encoding ferroxidases of the multicopper oxidase (MCO) gene family in an attempt to identify the ferroxidase partner of RiFTR1. Nine genes putatively encoding MCOs (RiMCO1-9) were identified. Yeast complementation assays demonstrated that RiMCO1 and RiMCO3 can function as ferroxidases, suggesting their involvement in the reductive Fe uptake pathway. Surprisingly, RiFTR1 was capable of transporting Fe in yeast without a ferroxidase partner, resembling the Fe transport mechanism of plant IRT1-like systems. RiFTR1 exhibited increase expression in arbuscules. Overexpression of RiFTR1 in Medicago truncatula roots led to enhanced mycorrhizal colonization and arbuscule abundance, highlighting the significance of Fe for AM symbiosis.

Empowering agriculture: The promise of zinc biofortification in rice

Zinc (Zn) plays a crucial role in metabolism in both plant and animal life. Zn deficiency is a worldwide problem that has recently gotten worse. This micronutrient shortage can be largely attributed to eating foods that are poor in zinc. If biofortification methods were widely used, Zn enrichment of the organ or tissue of interest would increase dramatically. However, Zn absorption mechanisms in rice plants must be understood on a fundamental level before these methods can be used effectively. Plant systems' Zn transporters and metal chelators play a major role in regulating this intricate physiological characteristic. The Zn efficiency of specific species is affected by a variety of factors, including the plant's growth stage, edaphic conditions, the time of year, and more. Both old and new ways of breeding plants can be used for biofortification. We have highlighted the significance of recombinant and genetic approaches to biofortifying in rice. In this review, we have the metabolic role of zinc in rice, and the different transporter families involved in the transportation of zinc in rice. We have also discussed the combined approaches of agronomic and genetic in zinc biofortification in rice and potential outcomes and future predictions.

X-ray fluorescence and XANES spectroscopy revealed diverse potassium chemistries and colocalization with phosphorus in the ectomycorrhizal fungus Paxillus ammoniavirescens

Ectomycorrhizal (ECM) fungi play a major role in forest ecosystems and managed tree plantations. Particularly, they facilitate mineral weathering and nutrient transfer towards colonized roots. Among nutrients provided by these fungi, potassium (K) has been understudied compared to phosphorus (P) or nitrogen (N). The ECM fungus Paxillus ammoniavirescens is a generalist species that interacts with the root of many trees and can directly transfer K to them, including loblolly pine. However, the forms of K that ECM fungi can store is still unknown. Here, we used synchrotron potassium X-ray fluorescence (XRF) and K-edge X-ray Absorption Near Edge Structure (XANES) spectroscopy on P. ammoniavirescens growing in axenic conditions to investigate the K chemistries accumulating in the center and the edge of the mycelium. We observed that various K forms accumulated in different part of the mycelium, including K-nitrate (KNO3), K-C-O compounds (such as K-tartrate K2(C4H4O6) and K-oxalate (K2C2O4)), K-S and K-P compounds. Saprotrophic fungi have been shown to excrete carboxylic acids, which in turn play a role in soil mineral weathering. Our finding of several K counter-ions to carboxylic acids may suggest that, besides their direct transfer to colonized roots, K ions can also be involved in the production of compounds necessary for sourcing nutrients from their surrounding environment by ECM fungi. Additionally, this work reveals that XANES spectroscopy can be used to identify the various forms of K accumulating in biological systems.

HcZnT2 is a highly mycorrhiza-induced zinc transporter from Hebeloma cylindrosporum in association with pine

Zinc (Zn) shortage is a common micronutrient deficiency affecting plants worldwide, while Zn toxicity may occur when this metal is in excess. Ectomycorrhizal (ECM) fungi are known to be able to modulate the transfer of macro- and microelements, among them Zn, to the plant. However, the underlying mechanisms are not well understood. We identified the HcZnT2 gene from the ECM fungus Hebeloma cylindrosporum, encoding a member of the Cation Diffusion Facilitator (CDF) family including Zn transporters, and analyzed its transcriptional regulation, the transport function by yeast complementation experiments, and its subcellular localization using a GFP fusion protein in yeast. HcZnT2 is highly induced during mycorrhization of Pinus pinaster, and upregulated in presence of the host plant root even without any direct contact. However, HcZnT2 is repressed by Zn excess conditions. By functional expression in yeast, our results strongly support the ability of HcZnT2 to transport Zn and, to a lesser extent, manganese. HcZnT2 localization was associated with the endoplasmic reticulum of yeast. Mycorrhizal gene activation at low external Zn suggests that the Zn transporter HcZnT2 might be important for the early establishment of the ECM symbiosis during Zn deficiency, rather than under Zn excess. HcZnT2 arises as an extremely remarkable candidate playing a key role in Zn homeostasis and regulation in ectomycorrhiza.

Integrating phytoremediation and mycoremediation with biosurfactant-producing fungi for hydrocarbon removal and the potential production of secondary resources

Treatment of petroleum-contaminated soil to a less toxic medium via physical and chemical treatment is too costly and requires posttreatment. This review focuses on the employment of phytoremediation and mycoremediation technologies in cleaning hydrocarbon-contaminated soil which is currently rare. It is considered environmentally beneficial and possibly cost-effective as it implements the synergistic interaction between plants and biosurfactant producing mycorrhiza to degrade hydrocarbon contaminants. This review also covers possible sources of hydrocarbon pollution in water and soil, toxicity effects, and current technologies for hydrocarbon removal and degradation. In addition to these problems, this review also discusses the challenges and opportunities of transforming the resultant treated sludge and treating plants into potential by-products for a higher quality of life for future generations.

The arbuscular mycorrhizal fungus Rhizophagus irregularis uses the copper exporting ATPase RiCRD1 as a major strategy for copper detoxification

Arbuscular mycorrhizal (AM) fungi establish a mutualistic symbiosis with most land plants. AM fungi regulate plant copper (Cu) acquisition both in Cu deficient and polluted soils. Here, we report characterization of RiCRD1, a Rhizophagus irregularis gene putatively encoding a Cu transporting ATPase. Based on its sequence analysis, RiCRD1 was identified as a plasma membrane Cu + efflux protein of the P1B1-ATPase subfamily. As revealed by heterologous complementation assays in yeast, RiCRD1 encodes a functional protein capable of conferring increased tolerance against Cu. In the extraradical mycelium, RiCRD1 expression was highly up-regulated in response to high concentrations of Cu in the medium. Comparison of the expression patterns of different players of metal tolerance in R. irregularis under high Cu levels suggests that this fungus could mainly use a metal efflux based-strategy to cope with Cu toxicity. RiCRD1 was also expressed in the intraradical fungal structures and, more specifically, in the arbuscules, which suggests a role for RiCRD1 in Cu release from the fungus to the symbiotic interface. Overall, our results show that RiCRD1 encodes a protein which could have a pivotal dual role in Cu homeostasis in R. irregularis, playing a role in Cu detoxification in the extraradical mycelium and in Cu transfer to the apoplast of the symbiotic interface in the arbuscules.

Mycorrhizal status and host genotype interact to shape plant nutrition in field grown maize (Zea mays ssp. mays)

Arbuscular mycorrhizal fungi (AMF) establish symbioses with the major cereal crops, providing plants with increased access to nutrients while enhancing their tolerance to toxic heavy metals. However, not all plant varieties benefit equally from this association. In this study, we used quantitative trait loci (QTL) mapping to evaluate the combined effect of host genotypic variation (G) and AMF across 141 genotypes on the concentration of 20 mineral elements in the leaves and grain of field grown maize (Zea mays spp. mays). Our mapping design included selective incorporation of a castor AMF-incompatibility mutation, allowing estimation of AMF, QTL and QTLxAMF effects by comparison of mycorrhizal and non-mycorrhizal plants. Overall, AMF compatibility was associated with higher concentrations of boron (B), copper (Cu), molybdenum (Mo), phosphorus (P), selenium (Se) and zinc (Zn) and lower concentrations of arsenic (As), iron (Fe), magnesium (Mg), manganese (Mn), potassium (K) and strontium (Sr). In addition to effects on individual elements, pairwise correlation matrices for element concentration differed between mycorrhizal and non-mycorrhizal plants. We mapped 22 element QTLs, including 18 associated with QTLxAMF effects that indicate plant genotype-specific differences in the impact of AMF on the host ionome. Although there is considerable interest in AMF as biofertilizers, it remains challenging to estimate the impact of AMF in the field. Our design illustrates an effective approach for field evaluation of AMF effects. Furthermore, we demonstrate the capacity of the ionome to reveal host genotype-specific variation in the impact of AMF on plant nutrition.

Influence of the urban environment on four mushroom species in the light of their elemental composition

The mushrooms are living organisms with excellent capability to adapt to the multiple challenges of their environment. Several species are well represented in urban green areas (parks, green spots, and recreation grounds). We investigated the influence of the urban environment over two saprotrophic (Bovista plumbea, Lycoperdon perlatum) and two mycorrhizal (Amanita rubescens, Suillus granulatus) species commonly present in urban parks of Cluj-Napoca, a major city of Romania. Three control sites close to the city were chosen. We determined 19 elements (Ag, Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Si, Sr, Ti, and Zn) in the fruiting bodies of mushrooms and in soils by ICP OES technique. S. granulatus was the most sensible species to the urban pollution; this species accumulated 130 and 4.40 mg kg^-1 (dry weight) median concentrations of Al and Ni, respectively. The highest concentration of Ag, Cu and Fe was determined in B. plumbea (3.18, 83.7 and 141 mg kg^-1, respectively) and L. perlatum (4.68, 91.0 and 125 kg^-1, respectively) collected from the city. The saprotrophic species contained appreciably higher concentrations of Ag, Cu, Fe, Mg, P, and S than the mycorrhizal ones. Common feature of all four species was the higher Ag and Sr concentrations in the fruiting bodies of urban origin. Our results suggest that the unique defence mechanisms of the species might have higher impact over the elemental profile of the mushrooms than the soil properties. We propose L. perlatum and S. granulatus as suitable indicator species of the urban pollution with regard to inorganic pollutants.

The function of the Medicago truncatula ZIP transporter MtZIP14 is linked to arbuscular mycorrhizal fungal colonization

Soil micronutrient availability, including zinc (Zn), is a limiting factor for crop yield. Arbuscular mycorrhizal (AM) fungi can improve host plant growth and nutrition through the mycorrhizal pathway of nutrient uptake. Although the physiology of Zn uptake through the mycorrhizal pathway is well established, the identity of the related molecular components are unknown. Here, RNA-seq analysis was used to identify genes differentially-regulated by AM colonization and soil Zn concentration in roots of Medicago truncatula. The putative Zn transporter gene MtZIP14 was markedly up-regulated in M. truncatula roots when colonized by Rhizophagus irregularis. MtZIP14 restored yeast growth under low Zn availability. Loss-of-function mutant plants (mtzip14) had reduced shoot biomass compared to the wild-type when colonized by AM fungi and grown under low and sufficient soil Zn concentration; at high soil Zn concentration, there were no genotypic differences in shoot biomass. The vesicular and arbuscular colonization of roots was lower in the mtzip14 plants regardless of soil Zn concentration. We propose that MtZIP14 is linked to AM colonization in M. truncatula plants, with the possibility that MtZIP14 function with AM colonization is linked to plant Zn nutrition.

Rhizophagus irregularis improves Hg tolerance of Medicago truncatula by upregulating the Zn transporter genes ZIP2 and ZIP6

Mercury (Hg) pollution of soils is a critical environmental problem. To rehabilitate Hg contaminated soils, arbuscular mycorrhizal (AM) fungi-based phytoremediation may be supportive, yet the functional potential of AM fungi in response to Hg exposure is unclear. In a greenhouse experiment, we assessed the response of Medicago truncatula (Hg tolerance index (TI), Hg partitioning) to different Hg concentrations [0 (Hg0), 25 (Hg25), 50 (Hg50) µg g^-1] in treatments with (AM) and without (NM) inoculation of Rhizophagus irregularis. Additionally, zinc (Zn) uptake and the expression of two Zn transporter genes (ZIP2, ZIP6) were examined because Zn is an essential element for plants and shares the same outer electronic configuration as Hg, implying potential competition for the same transporters. The results showed that AM plants had a higher TI than NM plants. Plant roots were identified as dominant Hg reservoirs. AM inoculation reduced the root Hg concentration under Hg50 compared to the NM treatment. There was an interaction between Hg treatment and AM inoculation on Hg stem concentration, i.e., at Hg25, AM inoculation decreased the Hg translocation from roots to stems, while Hg translocation was increased at Hg50 compared to the NM treatment. Zn acquisition was improved by R. irregularis. The negative relationship between Hg and Zn concentrations in the roots of AM and NM plants implied potential competition for the same transporters, although the expression of Zn transporters was upregulated by AM inoculation at all Hg levels. In conclusion, this baseline study demonstrated that R. irregularis may play an important role in Hg tolerance of M. truncatula, suggesting its potential for Hg-contaminated phytoremediation.

Physiological and metabolic dynamism in mycorrhizal and non-mycorrhizal Oryza sativa (var. Varsha) subjected to Zn and Cd toxicity: a comparative study

Arable lands getting contaminated with heavy metals have a very high negative impact on crop plants. The establishment of the mycorrhizal association with crop plants is a sustainable strategy to overcome metal toxicity. The major aim of this study was to analyze mycorrhizae-mediated alterations on the physiology and metabolism of Oryza sativa, as well as the impact of these alterations in the metal tolerance potential of the host on exposure to cadmium (Cd) and zinc (Zn) stresses. For this, 45 d old O. sativa (var. Varsha) plants inoculated with Claroideoglomus claroideum were exposed to 1.95 g Zn kg^-1 soil and 0.45 g Cd kg^-1 soil. Mycorrhization significantly increased shoot weight, root weight, moisture content, and chlorophyll biosynthesis under Cd and Zn stresses. Mycorrhization mitigated the oxidative stress elicited in O. sativa by the elevated Cd and Zn content, and it aided in maintaining the metabolite's level and rate of photosynthesis as compared to non-mycorrhizal plants. The circular-shaped unique structures seen as opening on the leaf surface of non-mycorrhizal plants under Zn stress, possibly for the emission of volatile compounds synthesized as a result of Zn stress, have a great chance of leaf tissue destruction. This structural modification was characterized in the case of Zn stress and not in Cd stress and can lead to the reduction of photosynthesis in O. sativa exposed to Zn stress. The reduction in oxidative stress could be correlated to the reduced uptake and transport of Cd and Zn ions in mycorrhizal plants. The exudation of tributyl acetyl citrate, 3-beta-acetoxystigmasta-4,6,22-triene, and linoleic acid from the mycorrhizal roots of rice plants has a crucial role in the stabilization of metal ions. This study proposes mycorrhization as a strategy to strengthen the Cd and Zn stress tolerance level of rice plants by regulating the physiology and metabolomics of the host plant.

Carbohydrate and lipid balances in the positive plant phenotypic response to arbuscular mycorrhiza: increase in sink strength

The exchange of phosphorus (P) and carbon (C) between plants and arbuscular mycorrhizal fungi (AMF) is a major determinant of their mutualistic symbiosis. We explored the C dynamics in tomato (Solanum lycorpersicum) inoculated or not with Rhizophagus irregularis to study their growth response under different NaH₂ PO₄ concentrations (Null P, 0 mM; Low P, 0.065 mM; High P, 1.3 mM). The percentage of AMF colonization was similar in plants under Null and Low P, but severely reduced under High P. However, the AMF mass biomarker 16:1ω5 revealed higher fungal accumulation in inoculated roots under Low P, while more AMF spores were produced in the Null P. Under High P, AMF biomass and spores were strongly reduced. Plant growth response to mycorrhiza was negative under Null P, showing reduction in height, biovolume index, and source leaf (SL) area. Under Low P, inoculated plants showed a positive response (e.g., increased SL area), while inoculated plants under High P were similar to non-inoculated plants. AMF promoted the accumulation of soluble sugars in the SL under all fertilization levels, whereas the soluble sugar level decreased in roots under Low P in inoculated plants. Transcriptional upregulation of SlLIN6 and SlSUS1, genes related to carbohydrate metabolism, was observed in inoculated roots under Null P and Low P, respectively. We conclude that P-limiting conditions that increase AMF colonization stimulate plant growth due to an increase in the source and sink strength. Our results suggest that C partitioning and allocation to different catabolic pathways in the host are influenced by AMF performance.

Ericoid mycorrhizal fungi as biostimulants for improving propagation and production of ericaceous plants

The mutualistic relationship between mycorrhizal fungi and plant roots is a widespread terrestrial symbiosis. The symbiosis enables plants to better adapt to adverse soil conditions, enhances plant tolerance to abiotic and biotic stresses, and improves plant establishment and growth. Thus, mycorrhizal fungi are considered biostimulants. Among the four most common types of mycorrhizae, arbuscular mycorrhiza (AM) and ectomycorrhiza (EcM) have been more intensively studied than ericoid mycorrhiza (ErM) and orchidaceous mycorrhiza (OrM). ErM fungi can form symbiotic relationships with plants in the family Ericaceae. Economically important plants in this family include blueberry, bilberry, cranberry, and rhododendron. ErM fungi are versatile as they are both saprotrophic and biotrophic. Increasing reports have shown that they can degrade soil organic matter, resulting in the bioavailability of nutrients for plants and microbes. ErM fungi can synthesize hormones to improve fungal establishment and plant root initiation and growth. ErM colonization enables plants to effective acquisition of mineral nutrients. Colonized plants are able to tolerate different abiotic stresses, including drought, heavy metals, and soil salinity as well as biotic stresses, such as pathogen infections. This article is intended to briefly introduce ErM fungi and document their beneficial effects on ericaceous plants. It is anticipated that the exploration of this special group of fungi will further improve our understanding of their value of symbiosis to ericaceous plants and ultimately result in the application of valuable species or strains for improving the establishment and growth of ericaceous plants.

Mechanisms of stress tolerance and their effects on the ecology and evolution of mycorrhizal fungi

Stress is ubiquitous and disrupts homeostasis, leading to damage, decreased fitness, and even death. Like other organisms, mycorrhizal fungi evolved mechanisms for stress tolerance that allow them to persist or even thrive under environmental stress. Such mechanisms can also protect their obligate plant partners, contributing to their health and survival under hostile conditions. Here we review the effects of stress and mechanisms of stress response in mycorrhizal fungi. We cover molecular and cellular aspects of stress and how stress impacts individual fitness, physiology, growth, reproduction, and interactions with plant partners, along with how some fungi evolved to tolerate hostile environmental conditions. We also address how stress and stress tolerance can lead to adaptation and have cascading effects on population- and community-level diversity. We argue that mycorrhizal fungal stress tolerance can strongly shape not only fungal and plant physiology, but also their ecology and evolution. We conclude by pointing out knowledge gaps and important future research directions required for both fully understanding stress tolerance in the mycorrhizal context and addressing ongoing environmental change.

Mycorrhiza-mediated potassium transport in Medicago truncatula can be evaluated by using rubidium as a proxy

Arbuscular mycorrhizal (AM) fungi considerably improve plant nutrient acquisition, particularly phosphorus and nitrogen. Despite the physiological importance of potassium (K⁺) in plants, there is increasing interest in the mycorrhizal contribution to plant K⁺ nutrition. Yet, methods to track K⁺ transport are often costly and limiting evaluation opportunities. Rubidium (Rb⁺) is known to be transported through same pathways as K⁺. As such our research efforts attempt to evaluate if Rb⁺ could serve as a viable proxy for evaluating K⁺ transport in AM symbiosis. Therefore, we examined the transport of K⁺ in Medicago truncatula colonized by the AM fungus Rhizophagus irregularis isolate 09 having access to various concentrations of Rb⁺ in custom-made two-compartment systems. Plant biomass, fungal root colonization, and shoot nutrient concentrations were recorded under sufficient and limited K⁺ regimes. We report that AM plants displayed higher shoot Rb⁺ and K⁺ concentrations and a greater K⁺:Na⁺ ratio relative to non-colonized plants in both sufficient and limited K⁺ conditions. Consequently, our results indicate that Rb⁺ can be used as a proxy to assess the movement of K⁺ in AM symbiosis, and suggest the existence of a mycorrhizal uptake pathway for K⁺ nutrition in M. truncatula.

Split down the middle: studying arbuscular mycorrhizal and ectomycorrhizal symbioses using split-root assays

Most land plants symbiotically interact with soil-borne fungi to ensure nutrient acquisition and tolerance to various environmental stressors. Among these symbioses, arbuscular mycorrhizal and ectomycorrhizal associations can be found in a large proportion of plants, including many crops. Split-root assays are widely used in plant research to study local and systemic signaling responses triggered by local treatments, including nutrient availability, interaction with soil microbes, or abiotic stresses. However, split-root approaches have only been occasionally used to tackle these questions with regard to mycorrhizal symbioses. This review compiles and discusses split-root assays developed to study arbuscular mycorrhizal and ectomycorrhizal symbioses, with a particular emphasis on colonization by multiple beneficial symbionts, systemic resistance induced by mycorrhizal fungi, water and nutrient transport from fungi to colonized plants, and host photosynthate allocation from the host to fungal symbionts. In addition, we highlight how the use of split-root assays could result in a better understanding of mycorrhizal symbioses, particularly for a broader range of essential nutrients, and for multipartite interactions.

The Invisible Hand of the Periodic Table: How Micronutrients Shape Ecology

Beyond the better-studied carbohydrates and the macronutrients nitrogen and phosphorus, a remaining 20 or so elements are essential for life and have distinct geographical distributions, making them of keen interest to ecologists. Here, I provide a framework for understanding how shortfalls in micronutrients like iodine, copper, and zinc can regulate individual fitness, abundance, and ecosystem function. With a special focus on sodium, I show how simple experiments manipulating biogeochemistry can reveal why many of the variables that ecologists study vary so dramatically from place to place. I conclude with a discussion of how the Anthropocene's changing temperature, precipitation, and atmospheric CO2 levels are contributing to nutrient dilution (decreases in the nutrient quality at the base of food webs).

Root fungal endophytes: identity, phylogeny and roles in plant tolerance to metal stress

Metal trace elements accumulate in soils mainly because of anthropic activities, leading living organisms to develop strategies to handle metal toxicity. Plants often associate with root endophytic fungi, including nonmycorrhizal fungi, and some of these organisms are associated with metal tolerance. The lack of synthetic analyses of plant-endophyte-metal tripartite systems and the scant consideration for taxonomy led to this review aiming (1) to inventory non-mycorrhizal root fungal endophytes described with respect to their taxonomic diversity and (2) to determine the mutualistic roles of these plant-fungus associations under metal stress. More than 1500 species in 100 orders (mainly Hypocreales and Pleosporales) were reported from a wide variety of environments and hosts. Most reported endophytes had a positive effect on their host under metal stress, but with various effects on metal uptake or translocation and no clear taxonomic consistency. Future research considering the functional patterns and dynamics of these associations is thus encouraged.

Occurrence and possible roles of polysaccharides in fungi and their influence on the development of new technologies

The article summarizes the roles of polysaccharides in the biology of fungi and their relationship in the development of new technologies. The comparative approach between the evolution of fungi and the chemistry of glycobiology elucidated relevant aspects about the role of polysaccharides in fungi. Also, based on the knowledge of fungal glycobiology, it was possible to address the development of new technologies, such as the production of new anti-tumor drugs, vaccines, biomaterials, and applications in the field of robotics. We conclude that polysaccharides activate pathways of apoptosis, secretion of pro-inflammatory substances, and macrophage, inducing anticancer activity. Also, the activation of the immune system, which opens the way for the production of vaccines. The development of biomaterials and parts for robotics is a promising and little-explored field. Finally, the article is multidisciplinary, with a different and integrated approach to the role of nature in the sustainable development of new technologies.