Julio Cesar Polonio

Antifungal and proteolytic activities of endophytic fungi isolated from Piper hispidum Sw

Endophytes are being considered for use in biological control, and the enzymes they secrete might facilitate their initial colonization of internal plant tissues and direct interactions with microbial pathogens. Microbial proteases are also biotechnologically important products employed in bioremediation processes, cosmetics, and the pharmaceutical, photographic and food industries. In the present study, we evaluated antagonism and competitive interactions between 98 fungal endophytes and Alternaria alternata, Colletotrichum sp., Phyllosticta citricarpa and Moniliophthora perniciosa. We also examined the proteolytic activities of endophytes grown in liquid medium and conducted cup plate assays. The results showed that certain strains in the assemblage of P. hispidum endophytes are important sources of antifungal properties, primarily Lasiodiplodia theobromae JF766989, which reduced phytopathogen growth by approximately 54 to 65%. We detected 28 endophytes producing enzymatic halos of up to 16.40 mm in diameter. The results obtained in the present study highlight the proteolytic activity of the endophytes Phoma herbarum JF766995 and Schizophyllum commune JF766994, which presented the highest enzymatic halo diameters under at least one culture condition tested. The increased activities of certain isolates in the presence of rice or soy flour as a substrate (with halos up to 17.67 mm in diameter) suggests that these endophytes have the potential to produce enzymes using agricultural wastes.

Genetic diversity of endophytic fungi from Coffea arabica cv. IAPAR-59 in organic crops

Endophytes are microorganisms that live inside plant tissues throughout its life cycle and during certain phases of development. The endophyte–host relationships can provide benefits to the host, protecting it against attack by insects and diseases. Several studies have demonstrated the diversity of endophytes from Coffea arabica, but few studies in varieties of organic crops. Thus, the objective in this study was to corroborate these reports with knowledge of the endophytic fungi communities in an organic variety of C. arabica L. cultivar IAPAR-59. We identified the endophytic fungi by molecular methods using the ITS1-5.8S-ITS2 region of rDNA and phylogenetic analyses. In the antagonist activity tests, the endophytes were tested against phytopathogens with the evaluation of the kind of interactions between them. Analyses demonstrated a diversity of genera, including: Colletotrichum, Trichoderma, Schizophyllum, Mycosphaerella, Cladosporium, and Cercospora, as well as the first record of the genus Ophiognomonia in C. arabica. The antagonist activity showed reduced growth of the phytopathogenic fungi Glomerella sp., Colletotrichum sp. and Sclerotinia sclerotiorum. The results obtained in this work, with the identification for the first time, of a highly diverse isolated endophytic of the species Ophiognomonia sp. in the coffee plants, is the second report of the detection of these fungi in Brazil. Also, the detection of different isolates with the ability to antagonise pathogens, emphasises the importance of further research, involving the isolation, identification and exploration of endophytes of other genetic varieties of coffee, obtained by breeding programs of this important crop in Brazil.

Curvulin and spirostaphylotrichins R and U from extracts produced by two endophytic Bipolaris sp. associated to aquatic macrophytes with antileishmanial activity

Abstract In the present study, biological activity and chemical composition of two crude extracts of endophytic fungal strains of Bipolaris genera isolated from two species of aquatic macrophytes: Eichhornia azurea (Kunth) and Eichhornia crassipes (Mart.) were investigated. The nuclear magnetic resonance and mass spectrometry data provided the identification of three main compounds: curvulin (1), spirostaphylotrichin R (2) and U (3). The fragmentation mechanism of the precursor ions towards collision induced dissociation (CID) tandem mass spectrometry experiment (MS/MS) is also proposed. Furthermore, biological screening of the crude extracts displayed antileishmanial activity with IC50 values ranging from 70–84.2 μg.mL−1.

Endophytic bacterial microbiome associated with leaves of genetically modified ( AtAREB1 ) and conventional (BR 16) soybean plants

Plant leaves (phyllosphere) have a great potential for colonization and microbial growth, consisting of a dynamic environment in which several factors can interfere with the microbial population structure. The use of genetically modified (GM) plants has introduced several traits in agriculture, such as the improvement of plant drought tolerance, as observed in the AtAREB1 transcription factor overexpression in soybean (Glycine max L. Merrill). The present study aimed at investigating the taxonomic and functional profile of the leaf microbial community of bacteria found in GM (drought-tolerant event 1Ea2939) and conventional (BR 16) soybean plants. Bacterial DNA was extracted from leaf samples collected from each genotype and used for microbial diversity and richness analysis through the MiSeq Illumina platform. Functional prediction was performed using the PICRUSt tool and the STAMP v 2.1.3 software. The obtainment of the GM event 1Ea2939 showed minimum effects on the microbial community and in the potential for chemical-genetic communication, i.e. in the potential for symbiotic and/or mutualistic interaction between plants and their natural microbiota.

Secondary Metabolites of Endophyte Fungi: Techniques and Biotechnological Approaches

Actually, special attention has been given to the exploration of new sources and new bioactive compounds. The microorganisms that inhabit specific habitats are potential source of new compounds, as the endophytes that inhabit the interior of plants without causing damage of host plant. This interaction needs the establishment of a chemical and genetic balance of the microbiome and host plant. Consequently, this interaction can generate new compounds of biotechnological interest. The problems of these studies involve the extraction, isolation, identification, and scale-up of production of specific molecules. Once these microorganisms are adapted to specific community and competition habitat, the axenic cultivation can alter the metabolism after the successive laboratory multiplication of these in artificial medium. This is one of the major problems to apply the endophytes on industrial chemical production. This chapter will discuss about the endophytic interaction with host plant, their capacity to produce bioactive compounds, and strategies to explore this potential.