Biological and Urea Treatments Reduce the Primary Inoculum of Red Leaf Blotch of Almond Caused by Polystigma amygdalinum.

Red leaf blotch (RLB), caused by Polystigma amygdalinum, is considered the most prevalent foliar disease in both traditional and new intensive almond-growing areas in Spain. Since the disease is monocyclic, its control must be based on the reduction of the only source of inoculum-the leaves infected in the previous season and fallen to the ground in autumn. Thus, this study aimed to determine the effect of two microorganisms and urea on RLB inoculum reduction by evaluating different application modes to fallen leaves in field conditions. Leaves of almond cv. Guara showing symptoms of RLB were collected in autumn, placed into nylon mesh bags, and treated by dipping or spraying with conidial suspensions of Myrothecium inundatum or the nonpathogenic strain Fusarium oxysporum FO12. The bags were exposed on the ground or buried in an experimental almond field for 6 months in each experimental year. Bags treated with crystalline urea solution at 46% N or not treated were included as controls. The primary inoculum (number of ascospores per gram of leaf) and the development of fruiting bodies (maturity stages of perithecia) were monitored in the fallen leaves for each experimental treatment combination. M. inundatum significantly reduced the primary inoculum in comparison with the nontreated control or F. oxysporum FO12, showing a similar effect to that observed for urea in the 2 experimental years. The type of application (spraying or dipping) did not show any significant effect, whereas the inoculum was significantly reduced in buried leaves in comparison with leaves maintained on the ground for all the treatments tested. This study represents the first report evaluating management strategies against RLB based on the reduction of the primary inoculum of P. amygdalinum.

First Report of Leaf Spot on Stephania tetrandra Caused by Albifimbria verrucaria in China.

Stephania tetrandra S. Moore belongs to the family Menispermaceae and is a Chinese medicinal plant widely distributed in tropical and subtropical regions of Asia and Africa. The root can be used for a variety of treatments (Jiang et al. 2020). In August 2021, leaf spot symptoms were observed on S. tetrandra cultivated in Jiangxi (114.456E, 27.379N, southern China). The disease symptoms included a slight constriction of the leaves, with irregularly shaped brown to black spots with well-defined borders. Severely affected leaves were shed by the plant. In order to determine the cause, symptomatic leaves were surface-disinfested with 0.6% NaOCl for 2 min, and rinsed twice in sterile water, then incubated on moist paper towels at 26°C in the dark for 2 days. Cream-colored sporodochia were observed within the leaf spots, turning dark green to black within 16 hours. A slow-growing white fungus was isolated from 95% of the samples (n = 30) on PDA. Dark green sporodochia emerged after 7 to 10 days of incubation, and released tip-end oval, non-septate, hyaline conidia measuring 6.7 to 8.5 µm (mean 7.5 µm, n = 50) by 2.0 to 3.3 µm (mean 2.7 µm, n = 50). Concentric rings were interspersed with sporodochia on the continually incubated mycelium. The morphological characteristics of the isolates matched the description of Albifimbria (Lombard et al. 2016). Nucleotide sequences, amplified from isolate FJL5C using primers of the internal transcribed spacer (ITS) (White et al. 1990), calmodulin (cmdA; Carbone and Kohn 1999), and RNA polymerase II second largest subunit (rpb2; O'Donnell et al. 2007), were deposited in GenBank under accession numbers OM317911, OM386815, and OM386816. A BLASTn analysis of the sequences showed 100% identity with the type strain CBS 328.52 (Lombard et al. 2016) of Albifimbria verrucaria (syn. Myrothecium verrucaria) for ITS, and 99% for cmdA and rpb2 (KU845893, KU845875, and KU845931, respectively). A phylogenetic tree generated using the three sequences showed that the isolate from S. tetrandra grouped with the A. verrucaria isolates, but away from other species of Albifimbria. These results together with the lack of a pale luteus exudate produced by A. viridis (Lombard et al. 2016) implied that the isolate was A. verrucaria. The culture was deposited in Guangdong Microbial Culture Collection Center (GDMCC 3.716). To verify pathogenicity, conidial suspension (106 conidia/mL in 0.05% Tween 20 solution) was sprayed onto six healthy plants. Six other plants sprayed with the Tween 20 solution alone served as controls. All plants were incubated in the dark at 26°C and 95% humidity for 30 hours, then transferred to a greenhouse at 26°C and 12 hours of illumination per day for 2 to 3 days. Inoculated leaves developed similar symptoms to those described above, whereas control plants remained healthy. The same pathogen was isolated from the diseased leaves, with the same morphological and molecular traits as those from the field plants. This experiment fulfilled Koch's postulates and confirmed that A. verrucaria causes leaf spots on S. tetrandra. This pathogen has been reported to cause disease in a wide range of weeds, legumes, and crop plants (Herman et al. 2020). To our knowledge, this is the first report of A. verrucaria causing leaf spots on S. tetrandra in natural or controlled environments. The disease can seriously threaten S. tetrandra on growth and yield loss.

Myrothins A-F from Endophytic Fungus Myrothecium sp. BS-31 Harbored in Panax notoginseng.

Endophytic fungi play important roles for host's stress tolerance including invasion by pathogenic microbes. Small molecules are common weapons in the microbe-microbe interactions. Panax notoginseng is a widely used traditional Chinese medicinal plant and harbors many endophytes, some exert functions against pathogens. Here, we report six new compounds named myrothins A-F (1-6) produced by Myrothecium sp. BS-31, an endophyte isolated from P. notoginseng, and their antifungal activities against pathogenic fungi causing host root-rot disease. Their structures were elucidated with analysis of spectroscopic data including 1D and 2D NMR, HR-ESI-MS. Myrothins B (2) and E (5) showed the weak activity against Fusarium oxysporum and Phoma herbarum, and myrothins F (6) showed weak activity against F. oxysporum.

Three New Fungal Leaf Spot Diseases of Spinach in the United States and the Evaluation of Fungicide Efficacy for Disease Management.

Leaf spot diseases of spinach, caused by Colletotrichum spinaciae, has become a major production constraint in several production areas, including Texas, in recent years. Leaf spot symptoms were observed in several fields in Texas in 2016 and 2017, with typical anthracnose-like symptoms and leaves with small, circular, and sunken lesions that appeared similar to injury from windblown sand. The lesions were plated on potato dextrose agar, from which fungal cultures were recovered. The fungi were identified based on morphology and sequence analysis of the introns of glutamate synthetase and glyceraldehyde-3-phosphate dehydrogenase (for isolates determined to be Colletotrichum spp.) and the internal transcribed spacer ribosomal DNA (for isolates determined to be Myrothecium spp.). Based on foliar symptoms, fungal colony and spore morphology, pathogenicity tests of fungal isolates on the spinach cultivar 'Viroflay', and DNA sequence analysis of the isolates, the symptoms on spinach leaves for two sets of samples were caused by Colletotrichum coccodes and Colletotrichum truncatum, and leaf spots resembling damage from windblown sand were caused by Myrothecium verrucaria. This is the first report of spinach leaf spot diseases caused by C. coccodes, C. truncatum, and M. verrucaria in the United States. C. coccodes and C. truncatum caused severe symptoms on the spinach cultivar 'Viroflay', whereas M. verrucaria caused symptoms of intermediate severity. Fungicide efficacy tests demonstrated that chlorothalonil, mancozeb, pyraclostrobin, fluxapyroxad + pyraclostrobin, and penthiopyrad were completely effective at preventing leaf spots caused by any of these pathogens when applied 24 h before inoculation of 'Viroflay' plants in greenhouse trials.

Keratomycosis Caused by a Rare Pathogen, Myrothecium verrucaria.

PURPOSE: To report a case of keratomycosis caused by a very rare pathogen, Myrothecium verrucaria. METHODS: This is a case report. A 53-year-old man complaint of left eye redness, irritation, intermittent pain after ashes entered his left eye. The patient was examined by slit lamp, anterior segment OCT and in vivo confocal microscopy. The HRT III-RCM image showed massive interlocking white thin lines in the cornea stroma. Corneal scrapings were collected for pathogen culture and PCR test. M. verrucaria was isolated and identified. RESULTS: Hourly topical natamycin (5%) and voriconazole (10 mg/ml) was given as well as intravenous fluconazole (200 mg per day). Treatment was continued with oral itraconazole, 200 mg/day, topical natamycin (5%), 4 times/day, and pranoprofen, 4 times/day. The therapy was tapered off over one and half a month. The cornea lesion healed with scar formation two months later. CONCLUSIONS: This is the first case report of M. verrucaria keratomycosis in China. We are the first to show the characteristic of M. verrucaria on cornea with In vivo confocal microscopy. A combination treatment of tropical natamycin, voriconazole and systemic fluconazole was effective in the treatment of M. verrucaria.

Bisphenol A Removal by the Fungus Myrothecium roridumIM 6482-Analysis of the Cellular and Subcellular Level.

Bisphenol (BPA) is a key ingredient in the production of epoxy resins and some types of plastics, which can be released into the environment and alter the endocrine systems of wildlife and humans. In this study, the ability of the fungus M. roridumIM 6482 to BPA elimination was investigated. LC-MS/MS analysis showed almost complete removal of BPA from the growth medium within 72 h of culturing. Products of BPA biotransformation were identified, and their estrogenic activity was found to be lower than that of the parent compound. Extracellular laccase activity was identified as the main mechanism of BPA elimination. It was observed that BPA induced oxidative stress in fungal cells manifested as the enhancement in ROS production, membranes permeability and lipids peroxidation. These oxidative stress markers were reduced after BPA biodegradation (72 h of culturing). Intracellular proteome analyses performed using 2-D electrophoresis and MALDI-TOF/TOF technique allowed identifying 69 proteins in a sample obtained from the BPA containing culture. There were mainly structural and regulator proteins but also oxidoreductive and antioxidative agents, such as superoxide dismutase and catalase. The obtained results broaden the knowledge on BPA elimination by microscopic fungi and may contribute to the development of BPA biodegradation methods.

Bionematicides as an alternative to methyl bromide fumigation.

Fumigant use in perennial crops can be reduced through prolonging the life of existing orchards. The longer an orchard remains healthy and productive, the less often it will be terminated, fumigated, and replanted. Two trials were conducted to determine the effectiveness of DiTera, a toxin produced by the fungus (Myrothecium verrucaria) and Nema-Q, an extract of the soap bark tree (Quillaja saponaria) for management of root-lesion (Pratylenchus vulnus) and ring (Mesocriconema xenopla) nematodes on walnuts. In the first trial, spring and fall treatments of DiTera were applied each year for four years to variety 'Chandler' scion on seedling 'Paradox' rootstock, and to own-rooted 'Chandler' trees. On 'Paradox' rootstock, both DiTera and Nema-Q increased walnut yields (P ≤ 0.05) and produced more vigorous trees (P ≤ 0.05) without significant reductions in nematode populations (P ≤ 0.05). A second trial was conducted with three rates of DiTera and four rates of Nema-Q, combinations of the two products, and an untreated control on 'Chandler' scion on 'Paradox' rootstock. The highest rate of Nema-Q (P ≤ 0.05), and a combination treatment of DiTera plus Nema-Q (P ≤ 0.05) increased trunk circumference. Several treatments showed reductions in root-lesion and ring nematodes (P ≤ 0.05). Bionematicides can improve yield, growth, and vigor in walnut orchards infested with plant-parasitic nematodes.

Isolation and Characterization of New Anti-Inflammatory and Antioxidant Components from Deep Marine-Derived Fungus Myrothecium SP. Bzo-l062.

In the present study, four new compounds including a pair of 2-benzoyl tetrahydrofuran enantiomers, namely, (-)-1S-myrothecol (1a) and (+)-1R-myrothecol (1b), a methoxy-myrothecol racemate (2), and an azaphilone derivative, myrothin (3), were isolated along with four known compounds (4-7) from cultures of the deep-sea fungus Myrothecium sp. BZO-L062. Enantiomeric compounds 1a and 1b were separated through normal-phase chiral high-performance liquid chromatography. The absolute configurations of 1a, 1b, and 3 were assigned by ECD spectra. Among them, the new compound 1a and its enantiomer 1b exhibited anti-inflammatory activity, inhibited nitric oxide formation in lipopolysaccharide-treated RAW264.7 cells, and exhibited antioxidant activity in the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and oxygen radical absorbance capacity assays.

Meroterpenoids and Isocoumarinoids from a Myrothecium Fungus Associated with Apocynum Venetum.

Four new meroterpenoids 1⁻4 and four new isocoumarinoids 5⁻8, along with five known isocoumarinoids (9⁻13), were isolated from the fungus Myrothecium sp. OUCMDZ-2784 associated with the salt-resistant medicinal plant, Apocynum venetum (Apocynaceae). Their structures were elucidated by means of spectroscopic analysis, X-ray crystallography, ECD spectra and quantum chemical calculations. Compounds 1⁻5, 7, 9 and 10 showed weak α-glucosidase inhibition with the IC50 values of 0.50, 0.66, 0.058, 0.20, 0.32, 0.036, 0.026 and 0.37 mM, respectively.

Functional and Transcriptomic Characterization of a Dye-decolorizing Fungus from Taxus Rhizosphere.

We isolated three laccase-producing fungus strains from Taxus rhizosphere. Myrotheium verrucaria strain DJTU-sh7 had the highest laccase activity of 216.2 U/ml, which was increased to above 300 U/ml after optimization. DJTU-sh7 had the best decolorizing effect for three classes of reactive dyes. The DJTU-sh7-containing fungal consortium displayed the robust decolorizing ability. Both color removal efficiency and chemical oxygen demand were increased in the consortium mediated biotransformation. Transcriptome changes of M. verrucaria elicited by azo dye and phenolic were quantified by the high throughput transcriptome sequencing, and the activities of the selected oxidases and reductases were determined. The possible involvement of oxidases and reductases, especially laccase, aryl alcohol oxidase, and ferric reductase in the biotransformation of dye and phenolic compounds was revealed at both transcriptomic and phenotypic levels. Revealing the transcriptomic mechanisms of fungi in dealing with organic pollutants facilitates the fine-tuned manipulation of strains in developing novel bioremediation and biodegradation strategies.We isolated three laccase-producing fungus strains from Taxus rhizosphere. Myrotheium verrucaria strain DJTU-sh7 had the highest laccase activity of 216.2 U/ml, which was increased to above 300 U/ml after optimization. DJTU-sh7 had the best decolorizing effect for three classes of reactive dyes. The DJTU-sh7-containing fungal consortium displayed the robust decolorizing ability. Both color removal efficiency and chemical oxygen demand were increased in the consortium mediated biotransformation. Transcriptome changes of M. verrucaria elicited by azo dye and phenolic were quantified by the high throughput transcriptome sequencing, and the activities of the selected oxidases and reductases were determined. The possible involvement of oxidases and reductases, especially laccase, aryl alcohol oxidase, and ferric reductase in the biotransformation of dye and phenolic compounds was revealed at both transcriptomic and phenotypic levels. Revealing the transcriptomic mechanisms of fungi in dealing with organic pollutants facilitates the fine-tuned manipulation of strains in developing novel bioremediation and biodegradation strategies.

De Novo Transcriptome Analysis of Plant Pathogenic Fungus Myrothecium roridum and Identification of Genes Associated with Trichothecene Mycotoxin Biosynthesis.

Myrothecium roridum is a plant pathogenic fungus that infects different crops and decreases the yield of economical crops, including soybean, cotton, corn, pepper, and tomato. Until now, the pathogenic mechanism of M. roridum has remained unclear. Different types of trichothecene mycotoxins were isolated from M. roridum, and trichothecene was considered as a plant pathogenic factor of M. roridum. In this study, the transcriptome of M. roridum in different incubation durations was sequenced using an Illumina Hiseq 2000. A total of 35,485 transcripts and 25,996 unigenes for M. roridum were obtained from 8.0 Gb clean reads. The protein-protein network of the M. roridum transcriptome indicated that the mitogen-activated protein kinases signal pathway also played an important role in the pathogenicity of M. roridum. The genes related to trichothecene biosynthesis were annotated. The expression levels of these genes were also predicted and validated through quantitative real-time polymerase chain reaction. Tri5 gene encoding trichodiene synthase was cloned and expressed, and the purified trichodiene synthase was able to catalyze farnesyl pyrophosphate into different kinds of sesquiterpenoids.Tri4 and Tri11 genes were expressed in Escherichia coli, and their corresponding enzymatic properties were characterized. The phylogenetic tree of trichodiene synthase showed a great discrepancy between the trichodiene synthase from M. roridum and other species. Our study on the genes related to trichothecene biosynthesis establishes a foundation for the M. roridum hazard prevention, thus improving the yields of economical crops.

Production of Laccase by a New Myrothecium verrucaria MD-R-16 Isolated from Pigeon Pea [Cajanus cajan (L.) Millsp.] and its Application on Dye Decolorization.

The present study was conducted to screen a laccase-producing fungal endophyte, optimize fermentation conditions, and evaluate the decolorization ability of the laccase. A new fungal endophyte capable of laccase-producing was firstly isolated from pigeon pea and identified as Myrothecium verrucaria based on a ITS-rRNA sequences analysis. Meanwhile, various fermentation parameters on the laccase production were optimized via response surface methodology (RSM). The optimal fermentation conditions were a fermentation time of five days, temperature 30 °C and pH 6.22. Laccase activity reached 16.52 ± 0.18 U/mL under the above conditions. Furthermore, the laccase showed effective decolorization capability toward synthetic dyes (Congo red, Methyl orange, Methyl red, and Crystal violet) in the presence of the redox mediator ABTS, with more than 70% of dyes decolorizing after 24 h of incubation. Additionally, the activity of laccase was relatively stable with pH (4.5-6.5) and a temperature range of 35-55 °C. Therefore, the high laccase production of the strain and the new fungal laccase could provide a promising alterative approach for industrial and environmental applications.

Cytotoxic trichothecene macrolides from the endophyte fungus Myrothecium roridum.

A new cytotoxic roridin-type trichothecene macrolide named epiroridin acid (1) and two known compounds epiroridin E (2) and mytoxin B (3) were isolated from the liquid culture of Myrothecium roridum A553, which was isolated from the medicinal plant Pogostemon cablin. The structure of the new macrolide (1) was elucidated by extensive spectroscopic measurements (UV, IR, MS, and 1D and 2D NMR) analyses. All isolated compounds (1-3) were evaluated for their cytotoxic activities against SF-268, MCF-7, NCI-H460, and HepG-2 tumor cell lines. The new compound (1) exhibited well cytotoxicity against the four selected tumor cell lines.

Genetic diversity and antimicrobial activity of endophytic Myrothecium spp. isolated from Calophyllum apetalum and Garcinia morella.

Calophyllum apetalum and Garcinia morella, medicinal plants are endemic to Western Ghats, Karnataka, India. Sixteen Myrothecium isolates were obtained from the tissues of bark and twigs of these plants. The purpose of this study was to explore the antimicrobial activity and genetic variability of the endophytic Myrothecium isolates. The antimicrobial activity as well as the genetic diversity of endophytic Myrothecium species was investigated through RAPD, ISSR and ITS sequence analysis. Myrothecium isolates were genotypically compared by RAPD and ISSR techniques, 510 and 189 reproducible polymorphic bands were obtained using 20 RAPD and ten ISSR primers respectively. The isolates grouped into four main clades and subgroups using unweighted pair group method with arithmetic mean cluster analysis. rDNA ITS sequence analysis presented better resolution for characterising the isolates of Myrothecium spp. The clustering patterns of the isolates were almost similar when compared with RAPD and ISSR dendograms. The results signify that RAPD, ISSR and ITS analysis can be employed to distinguish the genetic diversity of the Myrothecium species. The endophytic and pathogenic strains were compared by maximum parsimony, maximum likelihood and neighbour joining methods. One isolate (JX862206) amongst the 16 Myrothecium isolates exhibited potent antibacterial and as well as anti-Candida activity.

Bioherbicidal Activity of Albifimbria verrucaria (Formerly Myrothecium verrucaria) on Glyphosate-Resistant Conyza canadensis.

The effects of the bioherbicidal activity of the fungal phytopathogen, Albifimbria verrucaria (AV), formerly Myrothecium verrucaria, on glyphosate-resistant and -susceptible Conyza canadensis (horseweed) were examined in greenhouse and field studies. Spray applications of mycelial formulations of AV infected both glyphosate-resistant and -susceptible C. canadensis plants at various growth stages. Young plants in the rosette leaf stage of growth were controlled more efficaciously than were older plants that had bolted or that were in the inflorescence stage; nevertheless, severe injury and mortality also occurred in mature plants. The results indicate that this bioherbicidal fungus can infect and control C. canadensis, thereby demonstrating the potential of this fungus as a bioherbicidal agent against this troublesome weed, which has become resistant to various herbicides.

Removal of dye pollution by an oxidase derived from mutagenesis of the Deuteromycete Myrothecium with high potential in industrial applications.

It is estimated that over 700,000 tons of synthetic dyes are produced annually, 15% of which are emitted as effluents. These highly stable dyes enter the world water ecosystems and stay in the environment, and eventually cause adverse impacts to the environment. Current wastewater treatment methods, such as filtration, coagulation, and chemical oxidation, have sideeffects, including toxic residue formation, membrane fouling, bioaccumulation, and secondary pollutant formation. Given the issues mentioned, it is necessary to study how to improve the degradation of synthetic dye with a cost-effective and ecofriendly approach. Natural oxidation provides a greener option. Recently, Deuteromycetes fungus Myrothecium verrucaria G-1 (M. verrucaria G-1) has shown great potential in producing high level of dye oxidase. This study aims to generate a dye oxidase hyperproducer, 3H6 from M. verrucaria G-1 by using atmospheric and room temperature plasma (ARTP) coupled with ultraviolet (UV) irradiation. This method increases oxidase production by nearly 106.15%. After a simple precipitation and dialysis, this mutant oxidase increases by 1.97-fold in a specific activity with dye degradation rates at 70% for Mmethylene blue (MB) and 85% for Congo red (CR). It is found that the genetic stability of 3H6 remains active for ten generations. The size of oxidase is 65 kDa, and optimum temperature for reaction is 30 °C with 4.5 pH. This study presents that the first combined mutagenesis approach by ARPT-UV on fungus species generates an impressive increment of acid dye oxidases production. As such, this method presents a cost-effective alternative to mitigate hazardous dye pollution.

Myrothecol A, a new alkylresorcinol with cytotoxicity from Myrothecium sp.

A new alkylresorcinol, myrothecol A (1), along with two known ones (2 and 3), were isolated from a fungal strain Myrothecium sp. GY170016. Their structures were elucidated by extensive spectroscopic analysis. The absolute configuration of 1 was determined by electronic circular dichroism experiment. This is the first case of the presence of alkylresorcinols in genus Myrothecium. All the isolates were evaluated for their cytotoxic activities against human cancer cell line MCF-7 with IC50 values of 16.7, 13.2, 21.3 µM, respectively.

Taxonomy and phylogeny of Smaragdinisetamusae sp. nov. and Albifimbriaverrucaria (Hypocreales, Stachybotryaceae) on Musa from Thailand.

Background: Smaragdinisetamusae is introduced as a leaf-based novel saprobic species from Musa. Multi-gene phylogenetic analyses of internal transcribed spacer (ITS), RNA polymerase II second largest subunit (rpb2) and ß-tubulin (tub2) data support the taxonomic placement of the new collection in Smaragdiniseta (Hypocreales, Stachybotryaceae). The novel species is characterised by cup-shaped sporodochia covered by numerous peripheral setae and simple hyaline, guttulate conidia produced by the ultimate branches (phialides) of conidiophores. New information: This is the first report of Smaragdiniseta from Thailand and on Musaceae. In addition, we report Albifimbriaverrucaria for the first time from Thailand, based on morpho-molecular evidence.

Genome sequences of Rhizopogon roseolus, Mariannaea elegans, Myrothecium verrucaria, and Sphaerostilbella broomeana and the identification of biosynthetic gene clusters for fungal peptide natural products.

In recent years, a variety of fungal cyclic peptides with interesting bioactivities have been discovered. For many of these peptides, the biosynthetic pathways are unknown and their elucidation often holds surprises. The cyclic and backbone N-methylated omphalotins from Omphalotus olearius were recently shown to constitute a novel class (borosins) of ribosomally synthesized and posttranslationally modified peptides, members of which are produced by many fungi, including species of the genus Rhizopogon. Other recently discovered fungal peptide macrocycles include the mariannamides from Mariannaea elegans and the backbone N-methylated verrucamides and broomeanamides from Myrothecium verrucaria and Sphaerostilbella broomeana, respectively. Here, we present draft genome sequences of four fungal species Rhizopogon roseolus, Mariannaea elegans, Myrothecium verrucaria, and Sphaerostilbella broomeana. We screened these genomes for precursor proteins or gene clusters involved in the mariannamide, verrucamide, and broomeanamide biosynthesis including a general screen for borosin-producing precursor proteins. While our genomic screen for potential ribosomally synthesized and posttranslationally modified peptide precursor proteins of mariannamides, verrucamides, broomeanamides, and borosins remained unsuccessful, antiSMASH predicted nonribosomal peptide synthase gene clusters that may be responsible for the biosynthesis of mariannamides, verrucamides, and broomeanamides. In M. verrucaria, our antiSMASH search led to a putative NRPS gene cluster with a predicted peptide product of 20 amino acids, including multiple nonproteinogenic isovalines. This cluster likely encodes a member of the peptaibols, an antimicrobial class of peptides previously isolated primarily from the Genus Trichoderma. The nonribosomal peptide synthase gene clusters discovered in our screenings are promising candidates for future research.