Presence Of Endophytes Research Articles

A reliable method for Pseudomonas syringae pv. actinidiae detection in kiwifruit explants during in vitro propagation

According to recent statistics, in Italy a significant spread of the bacterial canker of Actinidia caused by Pseudomonas syringae pv. actinidiae (Psa) is recorded with peaks of 70 and 100%, and lower percentages ranging around 50%. The control of the Psa is a priority especially considering the hazard represented by the endophytic bacterial presence in nursery material. To evaluate the risk that could be associated with micropropagated shoots when using asymptomatic mother plants, Psa survival was studied in micro-propagated shoots of A. deliciosa 'Hayward' inoculated with different concentrations of a virulent Psa gfp-expressing/rifampicin-resistant strain (Psagfp-Rif(res)). Microbiological and molecular analysis were carried out at each in vitro transfer and on rooted plantlets in greenhouse. The Psagfp-Rif(res) reisolation on selective media confirmed by PCR analysis and by the ability to induce symptoms in Actinidia and HR in tobacco plants, was achieved in both the micropropagated materials and in the plants analyzed in toto after their re-establishment. A reliable and efficient method for Psa detection in nursery material is proposed to verify the presence Psa infection before symptom development.

Endophytic Root Colonization Patterns in Early and Mid-Spring Geophytes from Cluj County

Analysis of ten vernal ephemerals from Agro-Botanical Garden UASVM Cluj-Napoca revealed that all were naturally colonized by arbuscular mycorrhizae and fine root endophytes. Dark septate endophytes were observed in seven species. Highest frequency of arbuscular mycorrhizae colonization was found in Muscari armeniacum while second highest in Crocus vernus and Galanthus nivalis. High arbuscular mycorrhizae colonization frequency appears simultaneous with high fine root endophyte colonization in some species, but high arbuscular mycorrhizae frequency is not associated with highest dark septate endophyte presence. Lax arbuscular mycorrhizae symbiosis was identified in Iris reticulata and Hyacinthus orientalis. Plants with intensely arbuscular mycorrhizae colonized roots might be able to avoid carbon drain by allowing less arbuscules to form than presumed higher potential indicated by extensive length of root colonized by AMF hyphae.Analysis of ten vernal ephemerals from Agro-Botanical Garden UASVM Cluj-Napoca revealed that all were naturally colonized by arbuscular mycorrhizae and fine root endophytes. Dark septate endophytes were observed in seven species. Highest frequency of arbuscular mycorrhizae colonization was found in Muscari armeniacum while second highest in Crocus vernus and Galanthus nivalis. High arbuscular mycorrhizae colonization frequency appears simultaneous with high fine root endophyte colonization in some species, but high arbuscular mycorrhizae frequency is not associated with highest dark septate endophyte presence. Lax arbuscular mycorrhizae symbiosis was identified in Iris reticulata and Hyacinthus orientalis. Plants with intensely arbuscular mycorrhizae colonized roots might be able to avoid carbon drain by allowing less arbuscules to form than presumed higher potential indicated by extensive length of root colonized by AMF hyphae.

Tripartite Interactions Between Endophytic Fungi, Arbuscular Mycorrhizal Fungi, and Leymus chinensis.

Grasses often establish multiple simultaneous symbiotic associations with endophytic fungi and arbuscular mycorrhizal fungi (AMF). Many studies have examined pair-wise interactions between plants and endophytic fungi or between plants and AMF, overlooking the interplays among multiple endosymbionts and their combined impacts on hosts. Here, we examined both the way in which each symbiont affects the other symbionts and the tripartite interactions between leaf endophytic fungi, AMF, and Leymus chinensis. As for AMF, different species (Glomus etunicatum, GE; Glomus mosseae, GM; Glomus claroideum, GC; and Glomus intraradices, GI) and AMF richness (no AMF, single AMF taxa, double AMF mixtures, triple AMF mixtures, and all four together) were considered. Our results showed that significant interactions were observed between endophytes and AMF, with endophytes interacting antagonistically with GM but synergistically with GI. No definitive interactions were observed between the endophytes and GE or GC. Additionally, the concentration of endophytes in the leaf sheath was positively correlated with the concentration of AMF in the roots under low AMF richness. The shoot biomass of L. chinensis was positively related to both endophyte concentration and AMF concentration, with only endophytes contributing to shoot biomass more than AMF. Endophytes and AMF increased shoot growth by contributing to phosphorus uptake. The interactive effects of endophytes and AMF on host growth were affected by the identity of AMF species. The beneficial effect of the endophytes decreased in response to GM but increased in response to GI. However, no influences were observed with other GC and GE. In addition, endophyte presence can alter the response of host plants to AMF richness. When leaf endophytes were absent, shoot biomass increased with higher AMF richness, only the influence of AMF species identity outweighed that of AMF richness. However, when leaf endophytes were present, no significant association was observed between AMF richness and shoot biomass. AMF species identity rather than AMF richness promoted shoot growth. The results of this study demonstrate that the outcomes of interspecific symbiotic interactions are very complex and vary with partner identity such that the effects of simultaneous symbioses cannot be generalized and highlight the need for studies to evaluate fitness response of all three species, as the interactive effects may not be the same for each partner.

Transcriptome Analysis and Differential Expression in Tall Fescue Harboring Different Endophyte Strains in Response to Water Deficit

Two tall fescue [Lolium arundinaceum (Schreb.) Darbysh. = Schedonorus arundinaceus (Schreb.) Dumort. = Festuca arundinacea var. arundinacea Schreb.] plant genotypes with an Epichloë coenophiala (Morgan-Jones & W. Gams) C.W. Bacon & Schardl common toxic endophyte (CTE), one with a nontoxic strain (NTE19) and one with another Epichloë species (FaTG-4) were evaluated and compared with their respective endophyte-free clones for responses to water-deficit stress in the greenhouse. One of the plant genotypes (P27) showed a positive effect of its CTE strain on tiller production after stress and resumed watering. In transcriptome analysis of the pseudostems (leaf sheath whorls), differentially expressed genes (DEGs) were defined as having at least twofold expression difference and false discovery rate (FDR) < 0.05 in comparisons of water treatment (stressed or watered), endophyte presence or absence, or both. Stress affected 38% of the plant transcripts including those for the expected stress-response pathways. The DEGs affected by endophyte in stressed plants were unique to individual plant genotypes. In unstressed plants, endophyte presence tended to reduce expression of genes putatively for defense against fungi, but in unstressed P27 endophyte presence there was enhanced expression of dehydrin and heat shock protein genes. Our results indicated subtle and variable effects of endophytes on tall fescue gene expression; where the endophyte confers protection, its effects on plant gene expression may help prime the plant for stress resistance.

Rice carbohydrate dynamics regulate endophytic colonization of Diaporthe liquidambaris in response to external nitrogen

Abstract The fungal endophyte Diaporthe liquidambaris can establish mutualistic relationships with rice (Oryza sativa) and promote plant growth, specifically under low nitrogen (N) conditions, but the underlying mechanisms are largely unknown. The fungal nutritional status, which is based on host carbohydrate dynamics, determines symbiotic outcomes. In this study, an experiment with (E+) and without (E-) D. liquidambaris under low, moderate and high N conditions demonstrated that D. liquidambaris promoted chlorophyll biosynthesis and water-soluble carbohydrate (WSCs) accumulation in rice roots and root exudates under a lower N supply. In addition, D. liquidambaris grew better on substrates containing E+ root extracts in vitro due to the carbon (C) resource compared to that on E-treatments. Further experiments with manipulated environmental conditions (light and temperature) in vivo indicated that increased root WSCs were closely related to improved fungal colonization. We concluded that the presence of the fungal endophyte induced an enhanced mutualistic system by mediating host carbohydrate dynamics under N-poor conditions.

Fungi associated with Copaifera oblongifolia (Fabaceae) seeds: occurrence and possible effects on seed germination

ABSTRACT Copaifera oblongifolia is a recurrent plant species in degraded areas yet there is little information about its seed biology and interactions with fungi. The aims of this study were to identify the fungal community (endophytic and non-endophytic) associated with C. oblongifolia seeds and to test the effects of these different fungal species on germination. In general, germination of C. oblongifolia seeds was high (about 85 %), initiating four days after sowing and continuing for a total of 20 days. External asepsis with sodium hypochlorite did not influence germinability of C. oblongifolia. Seed infestation with Aspergillus niger, A. flavus, Mucor sp. and Rhizopus stolonifer did not affect the time required for germination, however, infection with A. flavus negatively affected germination percentage. Endophytic fungi were not isolated from C. oblongifolia seeds, suggesting that this species does not transmit endophytic fungi vertically. Therefore, C. oblongifolia can be classified in Class 3 with regard to the transmission and presence of endophytes.

Associations between root-inhabiting fungi and 40 species of medicinal plants with potential applications in the pharmaceutical and biotechnological industries

Medicinal plants are an important part of the health system in many countries around the world. However, to date, <1% of global herbal species have been studied in terms of their interactions with soil-borne fungi; this figure includes arbuscular mycorrhizal fungi (AMF), which have been found to enhance the performance of medicinal plants. The aims of the present investigation were to examine overall mycorrhizal status, morphology of arbuscular mycorrhiza (AM), degree of root colonisation by AMF, and richness and composition of AMF species in relation to 40 plant species collected from the Garden of Medicinal Plants affiliated with the Institute of Pharmacology of the Polish Academy of Sciences in Kraków. In addition, the presence of root endophytes that frequently co-occur with AMF, such as dark septate endophytes (DSEs) and Olpidium spp., was examined. We also tested correlations between fungal parameters and soil chemical properties. The survey showed the occurrence of AMF in 35 plant species. In 32 of these species, AMF were of the Arum morphotype. In the case of two plant species, the Paris type was found, while one plant represented the intermediate morphotype. DSEs were recorded within the roots of 11 species, Olpidium spp. in 10 species. Twenty-two common species of AMF were identified from spores isolated from soils from beneath the plant species. The most frequently occurring species were Funneliformis constrictum, F. mosseae, and Claroideoglomus claroideum. No significant correlation was found between fungal parameters and soil chemical properties. The results of this study expand our knowledge about the ecology of the plants under study. They may be also useful in further studies on the use of AMF inoculation to enhance production of secondary metabolites in these plants.

Identification and Frequencies of Endophytic Microbes within Healthy Grape Berries

Intact, healthy grape berries were sampled from vineyards in the states of Washington and New York; in Tasmania, Australia; and from bunches of table grapes exported from Chile that were purchased on two occasions in a United States supermarket. Endophytic microbes were isolated on media conducive to fungi or bacteria and subsequently identified by Illumina sequencing of their DNA. Species of the yeast genera Metschnikowia, Pichia, and Hanseniaspora were recovered from every set of samples, as were species of the bacterial genera Acinetobacter, Burkholderia, Bacillus, Acetobacter, and Gluconobacter. Multiple other fungal and bacterial species were recovered less often. When quantified for the Washington samples and one set from the supermarket, non-Saccharomyces yeast species represented the vast majority of fungal identifications, while the distribution of various bacterial species varied widely between and within the two sources. The endophytic presence of these microbes within grape berries has implications with respect not only to the potential development of sour rot, but also to the broader concept of microbial terroir in wine quality.

Detection of Burkholderia in the seeds of Psychotria punctata (Rubiaceae) - Microscopic evidence for vertical transmission in the leaf nodule symbiosis.

Background and aimsThe bacterial leaf nodule symbiosis is a close interaction between endophytes and their plant hosts, mainly within the coffee family. The interaction between Rubiaceae species and Burkholderia bacteria is unique due to its obligate nature, high specificity, and predominantly vertical transmission of the endophytes to the next generation of host plants. This vertical transmission is intriguing since it is the basis for the uniqueness of the symbiosis. However, unequivocal evidence of the location of the endophytes in the seeds is lacking. The aim of this paper is therefore to demonstrate the presence of the host specific endophyte in the seeds of Psychotria punctata and confirm its precise location. In addition, the suggested location of the endophyte in other parts of the host plant is investigated.MethodsTo identify and locate the endophyte in Psychotria punctata, a two-level approach was adopted using both a molecular screening method and fluorescent in situ hybridisation microscopy.Key resultsThe endophytes, molecularly identified as Candidatus Burkholderia kirkii, were detected in the leaves, vegetative and flower buds, anthers, gynoecium, embryos, and young twigs. In addition, they were in situ localised in leaves, flowers and shoot apical meristems, and, for the first time, in between the cotyledons of the embryos.ConclusionsBoth independent techniques detected the host specific endophyte in close proximity to the shoot apical meristem of the embryo, which confirms for the first time the exact location of the endophytes in the seeds. This study provides reliable proof that the endophytes are maintained throughout the growth and development of the host plant and are transmitted vertically to the offspring.

Multifaceted Interactions Between Endophytes and Plant: Developments and Prospects.

Microbial endophytes are present in all known plant species. The ability to enter and thrive in the plant tissues makes endophytes unique, showing multidimensional interactions within the host plant. Several vital activities of the host plant are known to be influenced by the presence of endophytes. They can promote plant growth, elicit defense response against pathogen attack, and can act as remediators of abiotic stresses. To date, most of the research has been done assuming that the interaction of endophytes with the host plant is similar to the plant growth-promoting (PGP) microbes present in the rhizosphere. However, a new appreciation of the difference of the rhizosphere environment from that of internal plant tissues is gaining attention. It would be interesting to explore the impact of endosymbionts on the host’s gene expression, metabolism, and other physiological aspects essential in conferring resistance against biotic and abiotic stresses. A more intriguing and inexplicable issue with many endophytes that has to be critically evaluated is their ability to produce host metabolites, which can be harnessed on a large scale for potential use in diverse areas. In this review, we discuss the concept of endophytism, looking into the latest insights related to the multifarious interactions beneficial for the host plant and exploring the importance of these associations in agriculture and the environment and in other vital aspects such as human health.

Leaf endophytes mediate fertilizer effects on plant yield and traits in northern oat grass (Trisetum spicatum)

Symbiotic fungi commonly increase plant acquisition of soil nutrients. Because prior work has focused on root fungi, we examined how leaf endophytes (Epichloe) influenced plant responses to fertilization and altered plant traits that may cascade to food webs and ecosystem processes. We manipulated endophyte presence/absence in two populations of Trisetum spicatum, a wild relative of oat, under a 2 × 2 addition of soil nitrogen (N) and phosphorus (P) in the greenhouse. Endophyte symbiosis altered how plant biomass responded to soil N and how plant traits responded to soil P. Endophytes boosted the biomass gains from N-fertilization in one population. Plants from a second population had weak benefits of symbiosis, but the endophyte altered plant traits, by increasing specific leaf area under P-fertilization, root diameter under low P, and concentration of the fungal alkaloid AcAP under N fertilization. Endophyte presence suppressed the typically observed increase in root hair density in response to soil P limitation. Under low P, symbiotic plants from both populations had improved forage quality relative to symbiont-free plants, although N-fertilization had a larger effect size on forage quality than did symbiosis. Finally, the two populations differed in production of fungal alkaloids, which generally increased in response to fertilization. Predicting how microbial symbionts mediate plant acquisition of nutrients requires understanding how much their effects vary among plant and endophyte genotypes. Here, the magnitude and direction of leaf symbionts’ effects on plant yield and traits varied between populations and with soil nutrient availability.

Distribution and diversity of foliar endophytic fungi in the mangroves of Andaman Islands, India

Abstract Fungal endophytes represent a major component of plant microbiomes. Various aspects of these fungi such as their diversity and technological potential have been studied in detail. However, their distribution and diversity in a mangrove community has not been addressed. In this study, we report the presence of culturable fungal endophytes from 20 obligate mangrove hosts from south Andaman Islands. Phomopsis/Diaporthe was isolated from all the mangrove species studied while Xylaria, Colletotrichum and Phyllosticta were recorded from the majority of the mangroves studied. A phylogenetic analysis of representative Phomopsis/Diaporthe isolates clearly indicated the broad host range of this genus. Our study also highlighted the fact that leaf endophytes of mangroves are not unique with reference to their species diversity and frequency of occurrence when compared to those of terrestrial plants. These observations suggest that the extraordinary success of some fungal endophytes in colonizing taxonomically disparate hosts could be due to development of traits specific to their ecosystem.

Influence of fungal endophytes on plant physiology is more pronounced under stress than well-watered conditions: a meta-analysis.

A meta-analysis of published articles shows that the influence of fungal endophytes on plant performance is dependent on plant water status. The magnitude of endophytic effects is higher in plants grown in water-limiting environments than those in adequate watering environments. The outcome of plant-endophyte interactions depends on the identity of the plant host and fungal symbionts. Water limitation often hinders plant productivity in both natural and agricultural settings. Endophytic fungal symbionts can mediate plant water stress responses by enhancing drought tolerance and avoidance, but these effects have not been quantified across plant-endophyte studies. A meta-analysis of published studies was performed to determine how endophytic fungal symbionts influence plant response under non-stressed versus water-stressed conditions. A significantly positive or neutral overall effect of fungal endophyte was noted under water-stressed conditions. In contrast, under non-stressed conditions, the overall effect of fungi on plants was mostly neutral. In general, the presence of fungal endophytes increased plant's total biomass, chlorophyll content, and stomatal conductance irrespective of water availability. In addition, plant shoot biomass, tiller density, plant height, maximum quantum yield (Fv/Fm), net photosynthesis, relative water content (RWC), amounts of ascorbate peroxidase (APX), glutathione (GSH), polyphenol oxidase (PPO), superoxide dismutase (SOD), and phenolics were significantly increased by endophyte colonisation under stressed conditions. Malondialdehyde (MDA) and hydrogen peroxide (H2O2) were reduced in endophytic plants under stress as compared with non-endophytic counterparts. Categorical analysis revealed that accumulation in plant biomass is influenced by factors such as host and fungi identity, the magnitude of which is greater under stressed than non-stressed conditions.

Endophytic Fungal strains Specifically Modified the Biochemical Status of Grape Cells

Previously, specific interactions in morphology were observed between grape cells and endophytic fungal strains during a dual culture experiment. However, the biochemical impacts of these fungal endophytes on grape cells is also expected due to their potential application in grape quality management. After assessed multiple physiochemical traits to those grape cells which have co-cultured with different endophytic fungal strains in this study, and found the presence of fungal endophytes obviously triggered ROS stress responses in grape cells, and the biochemical status in grape cells were differentially modified by different fungal strains. In those tested endophytic fungal strains, RH37 (Epicoccum sp.), RH6 (Alternaria sp.), RH32 (Alternaria sp.) and RH34 (Trichothecium sp.) conferred greater metabolic impacts on grape cells. And soluble protein (SPr), total flavonoids (TF), total phenols (TPh) and malondialdehyde (MDA) on the other hand, were sensitive biochemical parameters which can be influenced in greater ranges than other detected parameters. Most interestedly, fungal endophytes shaped metabolites patterns in grape cells during the dual culture appeared fungal genus/species/strain-specificity. The work confirmed the significance of fungal endophytes in grape metabolic regulation and elucidated the possibility to purposely manage grape quality using tool of fungal endophytes.

Hormonal and physiological changes driven by fungal endophytes increase Antarctic plant performance under UV-B radiation

Abstract Antarctic environments are amongst the most stressful habitats for life on Earth, with high intensities of solar UV-B radiation reaching the land surface. In this study, we evaluated how the photochemical efficiency, cell damage and reproductive biomass of Antarctic pearlwort (Colobanthus quitensis) were affected by different intensities of UV-B radiation in the absence and presence of fungal endophytes. In addition, we evaluated the hormonal content of plants at different UV-B radiation intensities and how hormonal content was affected by endophytes. Overall, plants exposed to UV-B radiation showed higher numbers of flowers, higher total biomass and lower lipid peroxidation in the presence of endophytes compared with plants without endophytes. Photochemical efficiency was unaffected. Fungal endophytes affected the content of salicylic acid, jasmonate, indole-3-acetate and abscisic acid in shoot tissue of plants exposed to UV-B radiation. These results suggest that endophytes could modulate the hormonal content of C. quitensis to improve its ecophysiological performance under high UV-B radiation.

Infection by the fungal endophyte Epichloë bromicola enhances the tolerance of wild barley (Hordeum brevisubulatum) to salt and alkali stresses

Salinization is considered as a major environmental threat to agricultural systems. Infection with Epichloe fungal endophytes has been shown to increase tolerance to NaCl stress for several host grass species, but limited information is available regarding the effects of these endophytes under mixed salt (NaCl and Na2SO4) and mixed alkali (NaHCO3 and Na2CO3) stresses. Since these four compounds are considered very harmful to many inland areas in China, we conducted a study to determine the impact of Epichloe fungal endophyte infection on wild barley (Hordeum brevisubulatum) under both salt stress (SS) and alkali stress (AS). Wild barley with (E+) and without (E-) Epichloe endophyte was subjected to mixed salt (molar ratio of NaCl:Na2SO4 = 1:1) and mixed alkali (molar ratio of NaHCO3:Na2CO3 = 1:1) treatments (0, 100, 200, 300 and 400 mM). Photosynthetic parameters and chlorophyll content were measured after 21 days exposure to stress, and growth parameters, physiological indexes, sodium (Na+), potassium (K+), calcium (Ca2+), nitrogen (N), phosphorus (P) and carbon (C) contents were determined after 22 days exposure to stress. The harmful effect of alkali stress on the growth of wild barley was stronger than those of salt stress, irrespective of endophyte infection. Alkali stress had a greater impact on photosynthesis and chlorophyll content compared to salt stress and also accumulated more of the osmoprotectant glycine betaine. However, salt stress appeared to increase total antioxidant capacity as well as increasing K+ content (resulting in a relative low Na+/K+ ratio). Under alkali stress, Ca2+ content sharply increased in roots as opposed to a decrease under salt stress. In roots, the C, N, P contents and the C:N ratio was higher under salt stress compared to alkali stress whereas the C:P and N:P ratios were lower. In shoots, the N and P contents were higher under salt stress compared to alkali stress whereas the C content and the C:P and C:N ratios were lower. Interestingly, the presence of Epichloe endophyte infection on wild barley under both salt stress and alkali stress led to significant amelioration of both stresses. Epichloe infection significantly increased photosynthesis, chlorophyll content, total antioxidant capacity and glycine betaine content, whilst lowering leaf malondialdehyde content. Furthermore, Epichloe infection reduced Na+ content, the Na+/K+ ratio and shoot Ca2+ content but increased K+ content and the root Ca2+ content. Epichloe infected plants also had higher C, N and P contents but lower ratios of C:N, C:P and N:P than uninfected plants. The presence of the Epichloe endophyte suppresses the negative effect of salt stress and alkali stress on wild barley seedling growth. The possible mechanisms by which the presence of Epichloe endophyte enhances growth of plants exposed to those two stresses include improved photosynthetic ability, increased antioxidant potential, increased nutrient absorption, and osmotic and ionic adjustment. The study also found that alkali stress is more harmful to wild barley than salt stress.

Jasmonic acid regulation of the anti‐herbivory mechanism conferred by fungal endophytes in grasses

Abstract The most studied mechanism of protection against herbivores in grasses associated with Epichloë fungal endophytes has been the fungal production of alkaloids. However, the contribution of the plant immune response on the level of resistance to herbivores in symbiotic grasses has been poorly explored. We studied the relationship between the plant hormone, jasmonic acid (JA) and Epichloë fungal endophytes on herbivore defences in symbiotic grasses. We hypothesized that an exogenous application of methyl jasmonate (MeJA), an activator of the plant JA defence response, would increase the level of resistance of endophyte‐symbiotic and non‐symbiotic plants to a chewing insect. As Epichloë endophytes produce alkaloids, an enhancement of the JA defence would complement the resistance given by these alkaloids. Lolium multiflorum plants symbiotic and non‐symbiotic with the endophyte Epichloë occultans were subjected to an exogenous application of MeJA followed by a challenge with the generalist chewing insect Spodoptera frugiperda. We measured the level of plant resistance to chewing insects, and the defences conferred by host plants and fungal endophytes. Symbiotic plants were more resistant to S. frugiperda than their non‐symbiotic counterparts. However, despite the fact that the concentration of JA significantly increased in all plants exposure to MeJA, neither endophyte‐symbiotic nor non‐symbiotic plants showed an enhanced resistance to insects. Unexpectedly, the exposure of endophyte‐symbiotic plants to MeJA led to a reduction in the concentration of loline alkaloids (i.e. N‐formyllolines and N‐acetylnorlolines), consequently decreasing the level of plant resistance to the herbivore. Synthesis. Our results suggest that, rather than complementing the alkaloid‐based defence, the jasmonic acid hormone weakens the anti‐herbivore mechanism conferred by Epichloë endophytes. The present study highlights that the interaction between the jasmonic acid hormone and the presence of leaf fungal endophytes can be of importance for the effectiveness of the anti‐herbivore defences of symbiotic plants.

Asexual Epichloë Endophytes Do Not Consistently Alter Arbuscular Mycorrhizal Fungi Colonization in Three Grasses

Abstract Plants commonly host multiple microbial symbionts that regulate productivity and other ecosystem processes, yet multi-symbiont interactions within hosts are rarely examined. We evaluated how the presence of aboveground Epichloe fungal endophytes (E+, symbiotic, and E−, endophyte experimentally removed) altered belowground colonization by arbuscular mycorrhizal fungi (AMF) in three grass species in a common environment. We sampled from E+ and E− populations of woodland bluegrass (Poa sylvestris A. Gray), grove bluegrass (Poa alsodes A. Gray), and tall fescue (Schedonorus arundinaceus Schreb.) in long-term experimental plots in woodlands near Nashville, Indiana. Endophyte symbiosis aboveground increased AMF colonization of roots in both Poa species, although this effect was only significant for hyphal colonization in P. sylvestris. Endophyte symbiosis did not significantly alter AMF colonization in S. arundinaceus, in contrast to prior findings for this species. Our results illustrate the effects o...

Isolation and molecular identification of four culturable endophytes from TV22 clone of Camellia sinensis (L.)

Endophytes are microorganisms presents within plant in asymptomatic manner and often act as a reservoir of novel bioactive secondary metabolites having antimicrobial, anti-insect and other beneficial properties. In absence of any reports on the presence of endophyte and their possible metabolic role in the process of infestation of tea plants (Camellia sinensis L.) by tea mosquito bug (Halopeltis theivora Waterhouse), the present study was undertaken to trace and isolate them from tea leaves for their molecular characterisation based on 16S rRNA sequencing. In this process, four endophytic bacteria have been identified as Brachybacterium sp. strain TMCS1, Bacillus pumilus strain TMCS2, Moraxella osloensis strain TMCS3 and Moraxella osloensis strain TMCS4 from the 2nd leaf of a young flash of C. sinensis (TV22 clone) which will enable us to study their culturable properties and role as biocontrol agents.

Co-inoculation of Lolium perenne with Funneliformis mosseae and the dark septate endophyte Cadophora sp. in a trace element-polluted soil.

The presence of dark septate endophytes (DSEs) or arbuscular mycorrhizal fungi (AMF) in plant roots and their effects on plant fitness have been extensively described. However, little is known about their interactions when they are simultaneously colonizing a plant root, especially in trace element (TE)-polluted soils. We therefore investigated the effects of Cadophora sp. and Funneliformis mosseae on ryegrass (Lolium perenne) growth and element uptake in a Cd/Zn/Pb-polluted soil. The experiment included four treatments, i.e., inoculation with Cadophora sp., inoculation with F. mosseae, co-inoculation with Cadophora sp. and F. mosseae, and no inoculation. Ryegrass biomass and shoot Na, P, K, and Mg concentrations significantly increased following AMF inoculation as compared to non-inoculated controls. Similarly, DSE inoculation increased shoot Na concentration, whereas dual inoculation significantly decreased shoot Cd concentration. Moreover, oxidative stress determined by ryegrass leaf malondialdehyde concentration was alleviated both in the AMF and dual inoculation treatments. We used quantitative PCR and microscope observations to quantify colonization rates. They demonstrated that DSEs had no effect on AMF colonization, while AMF colonization slightly decreased DSE frequency. We also monitored fluorescein diacetate (FDA) hydrolysis and alkaline phosphatase (AP) activity in the rhizosphere soils. FDA hydrolysis remained unchanged in the three inoculated treatments, but AMF colonization increased AP activity and P mobility in the soil whereas DSE colonization did not alter AP activity. In this experiment, we unveiled the interactions between two ecologically important fungal groups likely to occur in roots which involved a decrease of oxidative stress and Cd accumulation in shoots. These results open promising perspectives on the fungal-based phytomanagement of TE-contaminated sites by the production of uncontaminated and marketable plant biomass.