Heterologous Expression of Macrollins from Phytopathogenic Macrophomina phaseolina Revealed a Cytochrome P450 Mono-oxygenase in the Biosynthesis of β-Hydroxyl Tetramic Acid

Molecular interactions between the soilborne pathogenic fungus Macrophomina phaseolina and its host plants

Mentioned for the first time in an article 1971, the occurrence of the term "Macrophomina phaseolina" has experienced a steep increase in the scientific literature over the past 15 years. Concurrently, incidences of M. phaseolina-caused crop diseases have been getting more frequent. The high levels of diversity and plasticity observed for M. phasolina genomes along with a rich equipment of plant cell wall degrading enzymes, secondary metabolites and putative virulence effectors as well as the unusual longevity of microsclerotia, their asexual reproduction structures, make this pathogen very difficult to control and crop protection against it very challenging. During the past years several studies have emerged reporting on host defense measures against M. phaseolina, as well as mechanisms of pathogenicity employed by this fungal pathogen. While most of these studies have been performed in crop systems, such as soybean or sesame, recently interactions of M. phaseolina with the model plant Arabidopsis thaliana have been described. Collectively, results from various studies are hinting at a complex infection cycle of M. phaseolina, which exhibits an early biotrophic phase and switches to necrotrophy at later time points during the infection process. Consequently, responses of the hosts are complex and seem coordinated by multiple defense-associated phytohormones. However, at this point no robust and strong host defense mechanism against M. phaseolina has been described.

Therapeutic Potential of Methotrexate-Loaded Superparamagnetic Iron Oxide Nanoparticles Coated with Poly(lactic-co-glycolic acid) and Polyethylene Glycol against Breast Cancer: Development, Characterization, and Comprehensive In Vitro Investigation

Novel superparamagnetic iron oxide nanoparticles (SPIONs) of Methotrexate (MTX) were developed using supercritical liquid technology and optimized with a Box-Behnken design in order to assess its potential as a candidate for the treatment of breast cancer. MTX-SPIONs coated with poly(lactic-co-glycolic acid)-polyethylene glycol 400 had an aggregate size of 500 nm and an encapsulation efficiency of 46.8 ± 3.9%. The Fourier-transformed infrared spectroscopy analysis revealed a shift in the main bands due to intermolecular hydrogen bonds, whereas the differential scanning calorimetry analysis revealed the absence of the MTX melting endotherm, indicating complete encapsulation with oxide nanoparticles. The zeta potential results indicated a value of 4.98 mV, whereas the in vitro release study revealed an initial burst release followed by a considerable release of 35.1 ± 2.78% after 12 h. Using flow cytometry, control, MTX, and MTX-SPIONs were evaluated for apoptosis, with MTX-SPIONs exhibiting greater apoptosis than the control group and MTX. In addition, MTX-SPIONs inhibited cell division and content organization while substantially increasing the proportion of cells in the G1 and G2 phases relative to the control group. MTX-SPIONs exhibited prolonged anticancer effects against MCF-7 cell lines compared to MTX alone, indicating that SPION-delivered chemotherapeutics may increase cytotoxicity. The medication was stable with low encapsulated drug loss, suggesting that the supercritical liquid technology-based method is a promising way for generating drug-polymer magnetic composite nanoparticles for cancer treatment.

Discovery and biosynthesis of macrophasetins from the plant pathogen fungus Macrophomina phaseolina

3-Decalinoyltetramic acids (DTAs) are a class of natural products with chemical diversity and potent bioactivities. In fungal species there is a general biosynthetic route to synthesize this type of compounds, which usually features a polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) and a lipocalin-like Diels-Alderase (LLDAse). Using a synthetic biology approach, combining the bioinformatics analysis prediction and heterologous expression, we mined a PKS-NRPS and LLDAse encoding gene cluster from the plant pathogenic fungus Macrophomina phaseolina and characterized the cluster to be responsible for the biosynthesis of novel DTAs, macrophasetins. In addition, we investigated the biosynthesis of these compounds and validated the accuracy of the phylogeny-guided bioinformatics analysis prediction. Our results provided a proof of concept example to this approach, which may facilitate the discovery of novel DTAs from the fungal kingdom.

A genomic journey in the secondary metabolite diversity of fungal plant and insect pathogens: from functional to population genomics

Fungal pathogens produce a broad array of secondary metabolites (SMs), which allow the fungus to thrive in its natural habitat and gain competitive advantage. Analysis of the genetically encoded blueprints for SM assembly highlighted that only a small portion of the SMs these fungi are capable of producing are known, and even fewer have been investigated for their natural function. Using molecular tools, a lot of progress has been made recently in identifying the blueprint products and linking them to their ecological purpose such as the peptide virulence factor fusaoctaxin A released by Fusarium graminearum during infection of wheat or the F. oxysporum polyketide bikaverin that provides competitive advantage against bacteria in tomato. In addition, population genomics have given particularly important insights into the species-specific plasticity of the SM blueprint arsenal, showcasing the ongoing evolution and adaptation of fungal pathogens. This approach holds promise in inferring roles in pathogenicity of many more fungal SMs.