Photosynthetic temperature response of the Antarctic vascular plants Colobanthus quitensis and Deschampsia antarctica

The photosynthetic temperature response of the Antarctic vascular plants Colobanthus quitensis and Deschampsia antarctica was examined by measuring whole-canopy CO₂ gas exchange and chlorophyll (Chl) a fluorescence of plants growing near Palmer Station along the Antarctic Peninsula. Both species had negligible midday net photosynthetic rates (P_n) on warm, usually sunny, days (canopy air temperature [T_c]> 20°C), but had relatively high P_n on cool days (T_c<10°C). Laboratory measurements of light and temperature responses of P_n showed that high temperature, not visible irradiance, was responsible for depressions in P_n on warm sunny days. The optimal leaf temperatures (T_l) for P_n in C. quitensis and D. antarctica were 14 and 10°C, respectively. Both species had substantial positive P_n at 0°C T_l, which were 28 (C. quitensis) and 32% (D. antarctica) of their maximal P_n, and we estimate that their low-temperature compensation points occurred at ?2°C T_l (C. quitensis) and ?3°C (D. antarctica). Because of the strong warming trend along the peninsula over recent decades and predictions that this will continue, we were particularly interested in the mechanisms responsible for their negligible rates of P_n on warm days and their unusually low high-temperature compensation points (i.e., 26°C in C. quitensis and 22°C in D. antarctica). Low P_n at supraoptimal temperature (25°C) appeared to be largely due to high rates of temperature-enhanced respiration. However, there was also evidence for direct impairment of the photosynthetic apparatus at supraoptimal temperature, based on Chl fluorescence and P_n/intercellular CO₂ concentration (c_i) response curve analyses. The breakpoint or critical temperature (T_cr) of minimal fluorescence (F_o) was ≈42°C in both species, which was well above the temperatures where reductions in P_n were evident, indicating that thylakoid membranes were structurally intact at supraoptimal temperatures for P_n. The optimal T_l for photochemical quenching (q_p) and the quantum yield of photosystem II (PSII) electron transfer (φ_PSII) were 9 and 7°C in C. quitensis and D. antarctica, respectively. Supraoptimal temperatures resulted in lower q_p and greater non-photochemical quenching (q_NP), but had little effect on F_o, maximal fluorescence (F_m) or the ratio of variable to maximal fluorescence (F_v/F_m) in both species. In addition, carboxylation efficiencies or initial slopes of their P_n/c_i response were lower at supraoptimal temperatures, suggesting reduced activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Although continued warming along the peninsula will increase the frequency of supraoptimal temperatures, T_c at our field site averaged 4.3°C and was below the temperature optima for P_n in these species for the majority of diurnal periods (86%) during the growing season, suggesting that continued warming will usually improve their rates of P_n.     

Nitrogen form influences the response of Deschampsia antarctica to dark septate root endophytes

Fungi with dematiaceous septate hyphae, termed dark septate endophytes (DSE), are common in plant roots, particularly in cold-stressed habitats, but their effects on their host plants remain obscure. Here, we report a study that assessed the effects of six DSE on the growth and nutrient balance of Deschampsia antarctica when plants were supplied with the same amount of nitrogen in organic (casein hydrolysate) or inorganic (ammonium sulphate) form under controlled conditions. After 60 days, the DSE, that had each been isolated from D. antarctica and which analyses of internal transcribed spacer and large subunit regions indicated were similar to members of the Helotiales (Oculimacula yallundae, Mollisia and Tapesia spp.) and unassigned anamorphic ascomycetes, typically had no effect on, or reduced by 33–71%, shoot and root dry weights relative to uninoculated controls when plants had been supplied with nitrogen in inorganic form. In contrast, the DSE usually enhanced shoot and root dry weights by 51–247% when plants had been supplied with organic nitrogen. In the presence of inorganic nitrogen, only sporadic effects of DSE were recorded on shoot and root nitrogen or phosphorus concentrations, whereas in the presence of organic nitrogen, three to six of the DSE isolates increased shoot and root nitrogen and phosphorus contents. Most of the isolates decreased the phosphorus concentrations of shoots and roots when plants had been supplied with nitrogen in organic form. Our data suggest that DSE are able to mineralise peptides and amino acids in the rhizosphere, making nitrogen more freely available to roots.     

A meta-analysis of plant responses to dark septate root endophytes

? Dark septate endophytes (DSE) frequently colonize roots in the natural environment, but the effects of these fungi on plants are obscure, with previous studies indicating negative, neutral or positive effects on plant performance. ? In order to reach a consensus for how DSE influence plant performance, meta-analyses were performed on data from 18 research articles, in which plants had been inoculated with DSE in sterile substrates. ? Negative effects of DSE on plant performance were not recorded. Positive effects were identified on total, shoot and root biomass, and on shoot nitrogen (N) and phosphorus contents, with increases of 26-103% in these parameters for plants inoculated with DSE, relative to uninoculated controls. Inoculation increased total, shoot and root biomass by 52-138% when plants had not been supplied with additional inorganic N, or when all, or the majority, of N was supplied in organic form. Inoculation with the DSE Phialocephala fortinii was found to increase shoot and root biomass, shoot P concentration and shoot N content by 44-116%, relative to uninoculated controls. ? The analyses here suggest that DSE enhance plant performance under controlled conditions, particularly when all, or the majority, of N is available in organic form.     

Effects of ultraviolet-B radiation on leaf elongation, production and phenylpropanoid concentrations of Deschampsia antarctica and Colobanthus quitensis in Antarctica

Stratospheric ozone depletion by anthropogenic chlorofluorocarbons has lead to increases in ultraviolet‐B radiation (UV‐B; 280–320 nm) along the Antarctic Peninsula during the austral spring. We manipulated UV‐B levels around plants of Antarctic hair grass (Deschampsia antarctica; Poaceae) and Antarctic pearlwort (Colobanthus quitensis; Caryophyllaceae) for one field season near Palmer Station along the west coast of the Antarctic Peninsula. Treatments involved placing frames over naturally growing plants that either (1) held filters that absorbed most biologically effective radiation (UV‐B_BE; ‘reduced UV‐B’, 22% of ambient UV‐B_BE levels), (2) held filters that transmitted most UV‐B_BE (‘near‐ambient UV‐B’, 87% of ambient UV‐B_BE levels), or (3) lacked filters (‘ambient UV‐B’). Leaves on D. antarctica exposed to near‐ambient and ambient UV‐B were 16–17% shorter than those exposed to reduced UV‐B, and this was associated with shorter epidermal cells at the leaf base and tip. Leaves on C. quitensis exposed to near‐ambient and ambient UV‐B tended to be shorter (P=0.18) and epidermal cells at the leaf base tended to be smaller than those under reduced UV‐B (P<0.10). In order to further explain reductions in leaf length, we examined leaf concentrations of insoluble (cell‐wall bound) phenylpropanoids, since it has been proposed that wall‐bound phenylpropanoids such as ferulic acid may constrain cell expansion and leaf elongation. In both species, HPLC analysis revealed that ferulic and p‐coumaric acid were major components of both insoluble and soluble phenylpropanoids. Although there were no significant differences in concentrations between UV‐B treatments, concentrations of insoluble ferulic acid in D. antarctica tended to be higher under ambient and near‐ambient UV‐B than under reduced UV‐B (P=0.17). We also examined bulk‐leaf concentrations of soluble (methanol extractable) UV‐B‐absorbing compounds and found that concentrations were higher in plants exposed to near‐ambient and ambient UV‐B than in plants exposed to reduced UV‐B. We also assessed the UV‐B‐screening effectiveness of leaves that had developed on plants at the field site with a fiber‐optic microprobe. Leaf epidermal transmittance of 300‐nm UV‐B was 4.0 and 0.6% for D. antarctica and C. quitensis, respectively, which is low compared to grasses and herbaceous dicotyledonous plants found in more temperate climates. While the leaves of Antarctic vascular plants are relatively effective at screening UV‐B, levels of UV‐B in Antarctica are sufficient to reduce leaf epidermal cell size and leaf elongation in these species, although the mechanisms for these reductions remain unclear.     

Leishmanicidal and antitumoral activities of endophytic fungi associated with the Antarctic angiosperms Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth) Bartl.

A total of 564 isolates of endophytic fungi were recovered from the plants Deschampsia antarctica and Colobanthus quitensis collected from Antarctica. The isolates were screened against parasites Leishmania amazonensis and Trypanosoma cruzi and against the human tumour cell lines. Of the 313 fungal isolates obtained from D. antarctica and 251 from C. quitensis, 25 displayed biological activity. Nineteen extracts displayed leishmanicidal activity, and six inhibited the growth of at least one tumour cell line. These fungi belong to 19 taxa of the genera Alternaria, Antarctomyces, Cadophora, Davidiella, Helgardia, Herpotrichia, Microdochium, Oculimacula, Phaeosphaeria and one unidentified fungus. Extracts of 12 fungal isolates inhibited the proliferation of L. amazonesis at a low IC₅₀ of between 0.2 and 12.5 μg ml⁻¹. The fungus Phaeosphaeria herpotrichoides displayed only leishmanicidal activity with an IC₅₀ of 0.2 μg ml⁻¹, which is equivalent to the inhibitory value of amphotericin B. The extract of Microdochium phragmitis displayed specific cytotoxic activity against the UACC-62 cell line with an IC₅₀ value of 12.5 μg ml⁻¹. Our results indicate that the unique angiosperms living in Antarctica shelter an interesting bioactive fungal community that is able to produce antiprotozoal and antitumoral molecules. These molecules may be used to develop new leishmanicidal and anticancer drugs.     

Effects of dark septate endophytes on tomato plant performance

Non-mycorrhizal fungal root endophytes can be found in all natural and cultivated ecosystems, but little is known about their impact on plant performance. The impact of three mitosporic dark septate endophytes (DSE48, DSE49 and Leptodontidium orchidicola) on tomato plant characteristics was studied. Their effects on root and shoot growth, their influence on fruit yield and fruit quality parameters and their ability to diminish the impact of the pathogen Verticillium dahliae were investigated. While shoot biomass of young plants was enhanced between 10% and 20% by the endophytes DSE48 and L. orchidicola in one of two experiments and by DSE49 in both experiments, vegetative growth parameters of 24-week-old plants were not affected except a reproducible increase of root diameter by the isolate DSE49. Concerning fruit yield and quality, L. orchidicola could double the biomass of tomatoes and increased glucose content by 17%, but this was dependent on date of harvest and on root colonisation density. Additionally, the endophytes DSE49 and L. orchidicola decreased the negative effect of V. dahliae on tomato, but only at a low dosage of the pathogen. This indicates that the three dark septate endophytes can have a significant impact on tomato characters, but that the effects are only obvious at early stages of vegetative and generative development and currently too inconsistent to recommend the application of these DSEs in horticultural practice.     

Leaf functional and micro-morphological photoprotective attributes in two ecotypes of Colobanthus quitensis from the Andes and Maritime Antarctic

Colobanthus quitensis (Kunth) Bartl. (Cariophyllaceae) is distributed from Mexico to the Maritime Antarctic. It grows forming inconspicuous populations in humid and cold sites along high elevations in the Andes Mountains. Mediterranean Andes is characterized by a wider oscillation of diurnal and seasonal temperature, while the Maritime Antarctic is characterized by permanent low temperatures. Both places may experience high irradiance during sunny days (reaching up to 2,000 μmol photons m⁻² s⁻¹); however, the frequency of sunny days in the Maritime Antarctica is significantly lower (less than 20% of the whole growing season). We study whether acclimation to each environment relies on different photoprotective mechanisms. The Andean ecotype that has a longer growing season and a higher light integral reduces light absorption by the development of smaller chloroplasts with lower stacking granum area and down-regulation of Lhcb2. It also enhances the dissipation of the excess of absorbed energy by higher level of de-epoxidation of xanthophylls pool. On the other hand, the Antarctic ecotype which has developed under a shorter growing season, with lower total irradiance and continuous low temperatures, maximizes photochemical process even at low temperatures and it has a lower light-harvesting/core complex ratio and higher level of photoprotection supplied by an unusually high β-carotene and xanthophylls cycle pool. It resembles a well full light acclimated plant, probably due to higher excitation pressure imposed by lower temperature even at moderate irradiance. It is suggested that the biochemical plasticity of this species, highlighted by the development of these different strategies, is essential to cope successfully with these particular environments.     

Growth and metabolism of dark septate endophytes and their stimulatory effects on plant growth

Dark septate endophytes (DSE) colonize plant roots extensively and increase host plant growth and nutrition. However, the development of DSE-produced metabolites as plant biostimulants has been largely ignored. DSE growth curves and extracellular metabolite components were analyzed and the growth-promoting effects of DSE extracellular metabolites on alfalfa (Medicago sativa L.) grown for 4, 8 12, 16 and 20 days were evaluated. The growth curve of the DSE strain Alternaria sp. shows days 0-8 in the growth phase, days 8-16 in the stable phase, and days 16-20 in the senescent phase. The extracellular metabolite components of DSE were significantly different at different growth stages. The biomass of alfalfa was increased significantly by DSE extracellular metabolites (P < 0.05). Biomass of alfalfa inoculated with DSE extracellular metabolites more than doubled after growth for 8 days and nutrient availability also increased significantly compared with the uninoculated control. Six DSE extracellular metabolites, calycosin 7-galactoside, 1-[(5-amino-5-carboxypentyl)amino]-1-deoxyfructose, N2-fructopyranosylarginine, 2-(4-methyl-5-thiazolyl)ethyl hexanoate, kenposide B, and medinoside E, were significantly positively correlated with alfalfa biomass (P < 0.01). This study combines the DSE extracellular metabolites with plant and soil traits to provide a theoretical basis for the use of DSE metabolites in the product development of plant biostimulants.     

Low-temperature tolerance of the Antarctic species Deschampsia antarctica: A complex metabolic response associated with nutrient remobilization

The species Deschampsia antarctica (DA) is one of the only two native vascular species that live in Antarctica. We performed ecophysiological, biochemical, and metabolomic studies to investigate the responses of DA to low temperature. In parallel, we assessed the responses in a non-Antarctic reference species (Triticum aestivum [TA]) from the same family (Poaceae). At low temperature (4°C), both species showed lower photosynthetic rates (reductions were 70% and 80% for DA and TA, respectively) and symptoms of oxidative stress but opposite responses of antioxidant enzymes (peroxidases and catalase). We employed fused least absolute shrinkage and selection operator statistical modelling to associate the species-dependent physiological and antioxidant responses to primary metabolism. Model results for DA indicated associations with osmoprotection, cell wall remodelling, membrane stabilization, and antioxidant secondary metabolism (synthesis of flavonols and phenylpropanoids), coordinated with nutrient mobilization from source to sink tissues (confirmed by elemental analysis), which were not observed in TA. The metabolic behaviour of DA, with significant changes in particular metabolites, was compared with a newly compiled multispecies dataset showing a general accumulation of metabolites in response to low temperatures. Altogether, the responses displayed by DA suggest a compromise between catabolism and maintenance of leaf functionality.     

中国江西龙虎山崖顶植物根中深色有隔内生菌多样性

为探明丹霞地貌区崖顶植物深色有隔内生真菌（dark septate endophyte,DSE）多样性、群落组成以及生态分布规律。本文以江西龙虎山崖顶常见植物刺柏、马尾松、青冈栎、檵木、乌饭树、鸭跖草、苦槠、辣木树和香附子9种植物的根为研究对象,采用经典的组织分离方法分离DSE真菌,结合形态学特征和分子生物学数据研究丹霞地貌区崖顶常见植物DSE真菌多样性。结果表明：从9种植物根部990个组织块中,共分离纯化出404株菌株,经鉴定隶属于45个分类单元。其中,青霉属Penicillium、拟内孢霉属Endomycopsis、曲霉属Aspergillus、头囊霉属Ascocybe为优势属群,属种组成在不同植物中存在差异,且内生真菌属的数目与植物优势度极显著正相关（P<0.01）。9种植物深色有隔内生真菌（DSE）总分离率在0.51%-13.33%之间;各植物DSE Shannon指数在0.0743-1.0400之间,与植物优势度极显著正相关（P<0.01）,差异明显;Simpson指数较高（均值>0.7）且Pielou指数较低（均值<0.4）表明DSE真菌在不同植物分布不均匀;相似性指数普遍不高,在0.071-0.467之间。本研究初步揭示了丹霞地貌区崖顶深色有隔内生真菌的分布及多样性情况,为进一步探讨内生真菌在丹霞地貌等特殊生境的生态功能提供参考。     

Species composition and colonization of dark septate endophytes are affected by host plant species and soil depth in the Mu Us sandland,northwest China

Investigations into the edaphic associations, host affiliations and soil depth of dark septate endophytes (DSE) in arid desert environments can help explain their spatial distribution and the response mechanisms in desert ecosystems. Soils were sampled to a depth of 50 cm in the rhizospheres of Psammochloa villosa, Hedysarum laeve and Artemisia ordosica in the Mu Us sandland of northwest China in July 2015. The plant species and soil depth significantly influenced the distribution and colonization of DSE. Hyphal and total root colonization were significantly higher under P. villosa than the others in the 0–20 cm layer. The maximum colonization of P. villosa and H. laeve occurred in the 10–20 cm and 20–30 cm soil layers, respectively, while 30–40 cm soil layer under A. ordosica. Of twelve DSE species isolated from the roots of these plants, Phoma radicina and Bipolaris zeae were reported in desert ecosystems for the first time. Hyphal colonization was significantly and positively correlated with soil total nitrogen (TN) and significantly and negatively correlated with the soil carbon/nitrogen (C/N) ratio. Microsclerotial colonization was significantly and positively correlated with soil organic carbon (SOC), and total colonization was significantly and positively correlated with soil TN and total phosphorus (TP) and significantly and negatively correlated with soil C/N. Variation of DSE colonization was mostly attributed to effects of plant species. We concluded that the species composition and colonization of the DSE fungi were influenced by the plant species, soil depth and soil nutrient availability in this desert ecosystem. This research provides a basis for further understanding the ecological adaptability of DSE and their roles in promoting vegetation restoration and reducing desertification in arid ecosystems.     

Optimized protoplast isolation and establishment of transient gene expression system for the Antarctic flowering plant Colobanthus quitensis (Kunth) Bartl.

Plant Cell, Tissue and Organ Culture (PCTOC) - Colobanthus quitensis is one of two terrestrial plants that grow in the maritime Antarctic. Despite its important ecological niche in extreme...     

Negative effects on survival and performance of Norway spruce seedlings colonized by dark septate root endophytes are primarily isolate-dependent

Root endophytes are common and genetically highly diverse suggesting important ecological roles. Yet, relative to above-ground endophytes, little is known about them. Dark septate endophytic fungi of the Phialocephala fortinii s.l.-Acephala applanata species complex (PAC) are ubiquitous root colonizers of conifers and Ericaceae, but their ecological function is largely unknown. Responses of Norway spruce seedlings of two seed provenances to inoculations with isolates of four PAC species were studied in vitro. In addition, isolates of Phialocephala subalpina from two populations within and one outside the natural range of Norway spruce were also included to study the effect of the geographic origin of P. subalpina on host response. The interaction of PAC with Norway spruce ranged from neutral to highly virulent and was primarily isolate-dependent. Variation in virulence was much higher within than among species, nonetheless only isolates of P. subalpina were highly virulent. Disease caused by P. subalpina genotypes from the native range of Norway spruce was more severe than that induced by genotypes from outside the natural distribution of Norway spruce. Virulence was not correlated with the phylogenetic relatedness of the isolates but was positively correlated with the extent of fungal colonization as measured by quantitative real-time PCR.     

Differential growth promotion of poplar and birch inoculated with three dark septate endophytes in two trace element-contaminated soils

Dark septate endophytes (DSEs) are abundant in stressful environments, including trace element (TE)-enriched soils. However, knowledge about the effects of DSEs on plant growth in such soils is poor compared to the well-known mycorrhizal fungi. The aim of this work was to evaluate the effects of three DSE strains isolated from TE-contaminated soils on the growth and mineral nutrition of Betula pendula and Populus tremula x alba grown on two contrasting TE-polluted soils. The three DSEs evenly colonized the two plant species in both soils. Nevertheless, plant responses to DSE inoculation varied from neutral to beneficial depending on soil properties. Depending on fungal strain and plant species, different factors seemed to contribute to plant growth promotion. Phialophora mustea Pr27 and Leptodontidium Pr30 decreased lipid peroxidation in birch shoots. Chlorophyll, K, and P concentrations increased in the shoots of Leptodontidium Pr30-inoculated trees, whereas Cd concentration decreased in Cadophora Fe06-inoculated birch. The absence of a general DSE-mediated plant growth–promoting behavior could represent a limiting factor for a generic use of DSEs in the tree-based phytomanagement of TE-contaminated soils. Our results suggest that the selection of strains adapted to particular edaphic conditions should not be overlooked within the framework of phytomanagement.     

Host species and strain combination determine growth reduction of spruce and birch seedlings colonized by root-associated dark septate endophytes

Interactions of Betula pendula and Picea abies with dark septate endophytes of the Phialocephala fortinii-Acephala applanata species complex (PAC) were studied. PAC are ubiquitous fungal root symbionts of many woody plant species but their ecological role is largely unknown. Sterile birch and spruce seedlings in monoculture and mixed culture were exposed to four PAC strains, added either singularly or paired in all possible combinations at 18°C and 23°C. Plant and fungal biomass was determined after 4 months. The most significant factors were strain and host combination. One of the strains significantly reduced biomass gain of spruce but not of birch. Plant biomass was negatively correlated with total endophytic fungal biomass in half of the strain - plant combinations. Endophytic PAC biomass was four times higher in spruce (≈ 40 mg g(-1) drw) than in birch (≈ 10 mg g(-1) drw). Competition between strains was strain-dependent with some strains significantly reducing colonization density of other strains, and, thus, attenuating adverse effects of 'pathogenic' strains on plant growth in some strain - plant combinations. Biomass gain of spruce but not of birch was significantly reduced at higher temperature. In conclusion, host, fungal genotype, colonization density and presence of a competing PAC strain were the main determining factors for plant growth.     

Contrasting thermal acclimation of leaf dark respiration and photosynthesis of Antarctic vascular plant species exposed to nocturnal warming

Leaf respiration and photosynthesis will respond differently to an increase in temperature during night, which can be more relevant in sensitive ecosystems such as Antarctica. We postulate that the plant species able to colonize the Antarctic Peninsula – Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv. – are able to acclimate their foliar respiration and to maintain photosynthesis under nocturnal warming to sustain a positive foliar carbon balance. We conducted a laboratory experiment to evaluate the effect of time of day (day and night) and nocturnal warming on dark respiration. Short (E₀ and Q₁₀) and long‐term acclimation of respiration, leaf carbohydrates, photosynthesis (A_sat) and foliar carbon balance (R/A) were evaluated. The results suggest that the two species have differential thermal acclimation respiration, where D. antarctica showed more thermosensitivity to short‐term changes in temperature than C. quitensis. Experimental nocturnal warming affected respiration at daytime differentially between the two species, with a significant increase of R₁₀ and A_sat in D. antarctica, while no changes on respiration were observed in C. quitensis. Long thermal treatments of the plants indicated that nocturnal but not diurnal respiration could acclimate in both species, and to a greater extent in C. quitensis. Non‐structural carbohydrates were related with respiration in C. quitensis but not in D. antarctica, suggesting that respiration in the former species is likely controlled by total soluble sugars and starch during day and night, respectively. Finally, foliar carbon balance was differentially improved under warming conditions in Antarctic plants by different mechanisms, with C. quitensis deploying respiratory acclimation, while D. antarctica increased its A_sat.     

Colonization of roots of cultivated Solanum lycopersicum by dark septate and other ascomycetous endophytes

Tomato (Solanum lycopersicum L.) roots from four different crop sites in Colombia were surface sterilized and 51 fungal isolates were obtained and conserved for further analysis. Based on microscopical observations and growth characteristics, 20 fungal isolates corresponded to genus Fusarium, six presented asexual conidia different from Fusarium, eight were sterile mycelia, seven of which had dark septate hyphae and 17 did not continue to grow on plates after being recovered from conservation. Growth on different media, detailed morphological characterization and ITS region sequencing of the six sporulating and eight sterile isolates revealed that they belonged to different orders of Ascomycota and that the sterile dark septate endophytes did not correspond to the well known Phialocephala group. Interactions of nine isolates with tomato plantlets were assessed in vitro. No effect on shoot development was revealed, but three isolates caused brown spots in roots. Colonization patterns as analyzed by confocal microscopy differed among the isolates and ranged from epidermal to cortical penetration. Altogether 11 new isolates from root endophytic fungi were obtained, seven of which showed features of dark septate endophytes. Four known morphotypes were represented by five isolates, while six isolates belonged to five morphotypes of putative new unknown species.