Sarocladium spinificis, a new endophytic species from the coastal grass Spinifex littoreus in Taiwan

Can endophytic microbial compositions in cane roots be shaped by different propagation methods

In practical production, cane stems with buds are generally used as seed for propagation. However, long-terms cane stems only easily lead to some problems such as disease sensitivity, quality loss, etc. Recently, cane seedings, which are produced by tissue culture were used in sugarcane production, but few studies on cane health related to tissue culture seedings. Therefore, to evaluate the immunity and health of sugarcanes growing from different reproduction modes, the endophytic microbial compositions in cane roots between stem and tissue culture seedlings were analyzed using high-throughput techniques. The results showed that the endophytic microbial compositions in cane roots were significant differences between stem and tissue culture seedlings. At the genus level, Pantoea, Bacillus, Streptomyces, Lechevalieria, Pseudomonas, Nocardioides, unclassified_f__Comamonadaceae enriched as the dominant endophytic bacterial genera, and Rhizoctonia, Sarocladium, Scytalidium, Wongia, Fusarium, unclassified_f__Phaeosphaer, unclassified_c__Sordariom, unclassified_f__Stachybot, Poaceascoma, Microdochium, Arnium, Echria, Mycena and Exophiala enriched as the dominant endophytic fungal genera in cane roots growing from the tissue culture seedlings. In contrast, Mycobacterium, Massilia, Ralstonia, unclassified_f__Pseudonocardiacea, norank_f__Micropepsaceae, Leptothrix and Bryobacter were the dominant endophytic bacterial genera, and unclassified_k__Fungi, unclassified_f__Marasmiaceae, Talaromyces, unclassified_c__Sordariomycetes and Trichocladium were the dominant endophytic fungal genera in cane roots growing from stem seedlings. Additionally, the numbers of bacterial and fungal operational taxonomic units (OTUs) in cane roots growing from tissue culture seedlings were significantly higher than those of stem seedlings. It indicates that not only the endophytic microbial compositions in cane roots can be shaped by different propagation methods, but also the stress resistance of sugarcanes can be improved by the tissue culture propagation method.

Embellicines C-E: Macrocyclic Alkaloids with a Cyclopenta[b]fluorene Ring System from the Fungus Sarocladium sp

Macrocyclic alkaloids with a cyclopenta[b]fluorene ring system are a relatively young structural class of fungal metabolites, with the first members reported in 2013. Bioassay-guided fractionation of a Sarocladium sp. (fungal strain MSX6737) led to a series of both known and new members of this structural class (1-5), including the known embellicine A (1), three new embellicine analogues (2, 4, and 5), and a semisynthetic acetylated analogue (3). The structures were identified by examining both high-resolution electrospray ionization mass spectrometry data and one-dimensional and two-dimensional NMR spectra. The relative configurations of these molecules were established via 1H-1H coupling constants and nuclear Overhauser effect spectroscopy, while comparisons of the experimental electronic circular dichroism (ECD) spectra with the time-dependent density functional theory ECD calculations were utilized to assign their absolute configurations, which were in good agreement with the literature. These alkaloids (1-5) showed cytotoxic activity against a human breast cancer cell line (MDA-MB-231) that ranged from 0.4 to 4.8 μM. Compounds 1 and 5 were also cytotoxic against human ovarian (OVCAR3) and melanoma (MDA-MB-435) cancer cell lines.

The Introduction of Two New Species of Aquatic Fungi from Anzali Lagoon, Northern Iran

During a survey of aquatic fungi from Anzali Lagoon in Iran, several fungal specimens were isolated from freshwater habitats. Morphological evidence and comparing sequencing based on rDNA (ITS and LSU) and protein-coding genes (TEF1 and TUB2) showed that some isolates belong to undescribed fungal species. These isolates belong to Arthrobotrys and Sarocladium, two ascomycetes genera. Arthrobotrys hyrcanus, sp. nov., differs from closely related species such as A. dianchiensis by its larger conidia and septation of primary conidia. Sarocladium pseudokiliense, sp. nov., was similar to S. kiliense, but distinguished by its conidial shape and the absence of adelophialides and chlamydospores. Morphological descriptions, illustrations and multilocus phylogenetic analysis for both new species are provided.

Endophytic fungi isolated from plants present on a mine tailing facility show a differential growth response to lead

Plants growing in metal polluted sites can be a source of microorganisms suitable for bio-assisted phytoremediation strategies. In this work, three endophytic fungi from the roots of Poa stuckertii and Poa pratensis, two grasses that naturally colonize a Lead-Zinc tailing storage facility in Southern Chile, were isolated and identified. The leachate of the tailing sands showed a Pb content of 1.36 ± 0.71 ppm, and a pH of 7.3. By amplifying the ITS1/ITS4 region of fungal ribosomal DNA, the isolates were identified as Bjerkandera sp., Microdochium sp. and Sarocladium sp. When the growth media was supplemented with 50 ppm of Pb at pH 4.5, Microdochium sp. showed an 80% decrease in the biomass, but the biomass production of Bjerkandera sp. and Sarocladium sp. was not affected by the same treatment. The accumulation of Pb in Microdochium sp. increased as a function of the concentration of the metal in the growth media, between 48.3 μM and 241.3 μM. We showed that two Poaceae plants growing on a Lead-Zinc tailing storage facility are a source of endophyte fungi, and that Pb had a differential effect on the growth of the isolated fungi independent of the plant of origin.

Effect of the natural establishment of two plant species on microbial activity, on the composition of the fungal community, and on the mitigation of potentially toxic elements in an abandoned mine tailing

In Mexico, millions of tons of mining wastes are deposited in the open pit. Their content in potentially toxic elements (PTE) represents an environmental risk. In the tailings, pioneer plant communities are established, associated with a determined diversity of fungi; plants, and fungi are fundamental in the natural rehabilitation of mining wastes. The objective was to evaluate the impact of the natural establishment of two plant species on the microbial activity, on the composition of the fungal community, and on the mitigation of the effect of PTE in a contaminated mine tailing. In a tailing, we selected three sites: one non-vegetated; one vegetated by Reseda luteola, and one vegetated by Asphodelus fistulosus. In the substrates, we conducted a physical and chemical characterization; we evaluated the enzymatic activity, the mineralization of the carbon, and the concentration of PTE. We also determined the fungal diversity in the substrates and in the interior of the roots, and estimated the accumulation of carbon, nitrogen, phosphorus and PTE in plant tissues. The tailings had a high percentage of sand; the non-vegetated site presented the highest electric conductivity, and the plant cover reduced the concentration of PTE in the substrates. Plants increased the carbon content in tailings. The enzymatic activities of β-glucosidase and dehydrogenase, and the mineralization of carbon were highest at the site vegetated with A. fistulosus. Both plant species accumulated PTE in their tissues and exhibited potential in the phytoremediation of lead (Pb), cadmium (Cd), and copper (Cu). Fungal diversity was more elevated at the vegetated sites than in the bare substrate. Ascomycota prevailed in the substrates; the substrates and the plants shared some fungal taxa, but other taxa were specific. The plant coverage and the rhizosphere promoted the natural attenuation and a rehabilitation of the extreme conditions of the mining wastes, modulated by the plant species.

Antifungal activity of volatile compounds generated by endophytic fungi Sarocladium brachiariae HND5 against Fusarium oxysporum f. sp. cubense

The soil-born filamentous fungal pathogen Fusarium oxysporum f. sp. cubense (FOC), which causes vascular wilt disease in banana plants, is one of the most economically important Fusarium species. Biocontrol using endophytic microorganisms is among the most effective methods for controlling banana Fusarium wilt. In this study, volatile organic compounds (VOCs) showed strong antifungal activity against FOC. Seventeen compounds were identified from the VOCs produced by endophytic fungi Sarocladium brachiariae HND5, and three (2-methoxy-4-vinylphenol, 3,4-dimethoxystyrol and caryophyllene) showed antifungal activity against FOC with 50% effective concentrations of 36, 60 and 2900 μL/L headspace, respectively. Transmission electron microscopy (TEM) and double fluorescence staining revealed that 2-methoxy-4-vinylphenol and 3,4-dimethoxystyrol damaged the plasma membranes, resulting in cell death. 3,4-dimethoxystyrol also could induce expression of chitin synthases genes and altered the cell walls of FOC hyphae. Dichloro-dihydro-fluorescein diacetate staining indicated the caryophyllene induced accumulation of reactive oxygen species (ROS) in FOC hyphae. FOC secondary metabolism also responded to active VOC challenge by producing less fusaric acid and expressions of genes related to fusaric acid production were interrupted at sublethal concentrations. These findings indicate the potential of S. brachiariae HND5 as a biocontrol agent against FOC and the antifungal VOCs as fumigants.

Survival of the fittest: how the rice microbial community forces Sarocladium oryzae into pathogenicity

The fungus Sarocladium oryzae (Sawada) causes rice sheath rot and produces the phytotoxins cerulenin and helvolic acid. Both toxins show antimicrobial activity but only helvolic acid production in the rice sheath correlates with virulence. Sarocladium oryzae isolates that differ in their toxin production were used to study their interaction with the rice culturable bacterial endophyte community. The diversity and community structure was defined in the edge of sheath rot lesions, followed by a null model-based co-occurrence analysis to discover pairwise interactions. Non-random pairs were co-cultured to study the nature of the interactions and the role of the toxins herein. Compared to healthy sheaths, endophyte diversity strongly increased when infected with the least virulent S. oryzae isolates producing low amounts of toxins. Virulent S. oryzae isolates did not affect diversity but caused strong shifts in species composition. The endophyte community of healthy rice plants was dominated by B. cereus. This bacterium was enriched in lesions produced by low-virulent S. oryzae isolates and caused hyphal lysis. Contrarily, helvolic acid producers eliminated this bacterium from the sheath endosphere. We conclude that S. oryzae needs to produce antibiotics to defend itself against antagonistic rice endophytes to successfully colonize and infect the rice sheath.

Additions to Phaeosphaeriaceae (Pleosporales): Elongaticollum gen. nov., Ophiosphaerella taiwanensis sp. nov., Phaeosphaeriopsis beaucarneae sp. nov. and a new host record of Neosetophoma poaceicola from Musaceae

A novel ascomycetous genus, Elongaticollum, occurring on leaf litter of Hedychium coronarium (Zingiberaceae) in Taiwan, is described and illustrated. Elongaticollum is characterized by dark brown to black, superficial, obpyriform, pycnidial conidiomata with a distinct elongate neck, and oval to oblong, hyaline, aseptate conidia. Phylogenetic analyses (maximum likelihood, maximum parsimony and Bayesian) of combined ITS, LSU, SSU and tef1-α sequence data revealed Elongaticollum as a distinct genus within the family Phaeosphaeriaceae with high statistical support. In addition, Ophiosphaerella taiwanensis and Phaeosphaeriopsis beaucarneae are described as new species from dead leaves of Agave tequilana and Beaucarnea recurvata (Asparagaceae), respectively. Neosetophoma poaceicola is reported as a new host record from dead leaves of Musa acuminata (Musaceae). Newly described taxa are compared with other similar species and comprehensive descriptions and micrographs are provided.

Genera of phytopathogenic fungi: GOPHY 3

This paper represents the third contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions, information about the pathology, distribution, hosts and disease symptoms for the treated genera, as well as primary and secondary DNA barcodes for the currently accepted species included in these. This third paper in the GOPHY series treats 21 genera of phytopathogenic fungi and their relatives including: Allophoma, Alternaria, Brunneosphaerella, Elsinoe, Exserohilum, Neosetophoma, Neostagonospora, Nothophoma, Parastagonospora, Phaeosphaeriopsis, Pleiocarpon, Pyrenophora, Ramichloridium, Seifertia, Seiridium, Septoriella, Setophoma, Stagonosporopsis, Stemphylium, Tubakia and Zasmidium. This study includes three new genera, 42 new species, 23 new combinations, four new names, and three typifications of older names.

Occurrence of Mycotoxigenic Fusarium Species and Competitive Fungi on Preharvest Maize Ear Rot in Poland

Maize has become one of the most important crops for food and feed production-both as a silage and crop residue worldwide. The present study aimed to identify the co-occurrence of Fusarium subglutinans, Fusarium verticillioides, Trichoderma atroviride, Sarocladium zeae, and Lecanicillium lecanii on maize ear rot. Further, the accumulation of mycotoxins as secondary metabolites of Fusarium spp. in maize ear samples was also analyzed. Maize ear samples were collected between 2014 and 2017 from two main maize growing areas in Poland (Greater Poland and Silesia region). A significant difference was found in the frequency of two main Fusarium spp. that infect maize ears, namely F. subglutinans and F. verticillioides. In addition to Fusarium spp. T. atroviride, S. zeae, and L. lecanii were also identified. T. atroviride species was found in 14% of maize samples examined between 2014 and 2017, particularly with a high percentage of Trichoderma spp. recorded in 2014, i.e., in 31% of samples. However, mycotoxin content (beauvericin and fumonisins) varied, depending on both the location and year of sampling. The interaction of fungi and insects inhabiting maize ear and kernel is very complex and not yet elucidated. Therefore, further research is required in this area.

Diversity of Endophytic Fungi of the Coastal Plant Vitex rotundifolia in Taiwan

Vitex rotundifolia L. f. (Lamiaceae), which commonly grows at sand coasts, is important for coast protection and the prevention of erosion. However, the diversity and roles of fungi associated with this plant remain unclear. A total of 1,052 endophytic isolates from 1,782 plants tissues from two sand beaches in northern Taiwan were classified into 76 morphospecies based on culture morphology and ITS or LSU rRNA gene sequence comparisons. Critical species were further identified using protein gene sequences and microscopy. Most of the isolates at both sites belonged to the phylum Ascomycota, with Pleosporales having the most species (15 species). The largest number of isolates (47.7%) was from the stems, followed by the roots (22.5%), leaves (16.6%), and branches (13.1%). The three species with the highest isolation frequencies at both sites were Alternaria alternata, Aspergillus terreus, and an undescribed species of Alpestrisphaeria. A. terreus was found in all organs. A. alternata was detected in all organs, except the roots. Alpestrisphaeria sp. was only found in the roots and stems. In the stems and roots, strain numbers from cortical tissues were approximately two-fold higher than those from the corresponding woody tissue. The overall colonization rate in the stems was significantly higher than those that in the roots and leaves. The majority of fungi appeared to be saprobes, which may play important roles in nutrient recycling during sand burial and mediate further stress factors in the coastal habitat.

A case of bilateral otomycosis associated with Aspergillus flavus and A. terreus in Taiwan

Otitis externa caused by fungi (otomycosis) occurs more commonly in tropical areas with high moisture than in temperate regions. Bilateral otomycosis is, however, rarely reported. In a case of bilateral otitis externa in a 56-year-old male patient in Taiwan, direct microscopic examination of the cerumen as well as isolation of strains indicated the presence of two Aspergillus species being different in each of both ears. The species were identified by DNA sequence comparisons and additional morphological confirmation of diagnostic characteristics as Aspergillus flavus and Aspergillus terreus. The rarely reported occurrence of two Aspergillus species in otitis of the same patient deserves attention in other cases of otomycosis, particularly with respect to potentially different resistances of different species against antifungals. Treatment with nystatin/neomycin was not successful, but with clotrimazole was effective.

Fungal endophytes as prolific source of phytochemicals and other bioactive natural products: A review

Endophytic fungi are those that live internally in apparently healthy and asymptomatic hosts. Endophytic fungi appear to be ubiquitous; indeed, no study has yet shown the existence of a plant species without endophytes. High species diversity is another characteristic of endophytic mycobiota which is depicted by the fact that it is quite common for endophyte surveys to find assemblages consisting of more than 30 fungal species per host plant species. Medicinal plants had been used to isolate and characterize directly the bioactive metabolites. However, the discovery of fungal endophytes inside these plants with capacity to produce the same compounds shifted the focus of new drug sources from plants to fungi. Bioactive natural products from endophytic fungi, isolated from different plant species, are attracting considerable attention from natural product chemists and biologists alike which is clearly depicted by the steady increase of publications devoted to this topic during the recent years. This review will highlight the chemical potential of endophytic fungi with focus on the detection of pharmaceutically valuable plant constituents as products of fungal biosynthesis. In addition, it will cover newly discovered endophytic fungi and also new bioactive metabolites reported in recent years from fungal endophytes. It summarizes the up-to-date and comprehensive information on bioactive compounds from endophytic fungi by having done a thorough survey of literature.