Molecular identification of Brazilian Fusarium strains: sources of proteases with milk-clotting properties.

Fusarium is a genus of ubiquitous fungi that comprises mycotoxigenic animal and plant pathogens. These fungi have the ability to exploit a wide range of substrates and hosts, indicating their great potential for enzyme production; however, this aspect is understudied. Therefore, the present study aimed for revaluating the identity of twenty-three Fusarium strains maintained in the University Recife Mycology (URM) culture collection, Brazil, and to evaluate their potential for proteases production and the milk-clotting activity of these proteases. According to phylogenetic analysis of translation elongation factor 1-alpha (TEF1) gene partial sequences, these strains belonged to 12 species representing four species complexes: Fusarium concolor, F. fujikuroi, F. incarnatum-equiseti, and F. oxysporum. Four of these species are putatively novel to science. Notably, novel associations of Fusarium spp. with certain hosts/substrates were documented. The proteolytic activity ranged from 1.67 U ml-1 to 22.03 U ml-1 among the evaluated fungal isolates, with specific proteolytic activity reaching 205.86 U mg-1. The values for coagulant activity and specific activity were up to 157.14 U ml-1 and 1,424.11 U mg-1, respectively. These results indicate the potential of URM Fusarium strains as a source for the production of enzymes of industrial interest. Additionally, they reinforce the importance of applying DNA-based methods for reviewing the identification of fungal strains preserved in biodiversity repositories.

Aspergillus andPenicillium (Eurotiales: Trichocomaceae) in soils of the Brazilian tropical dry forest: diversity in an area of environmental preservation

ResumenEl suelo es un sistema biológico complejo, que desempeña un papel fundamental en las plantas y los animales, especialmente en los bosques secos como la Caatinga. Los hongos del suelo, tales como Aspergillus y Penicillium, pueden ser utilizados como bioindicadores para la conservación de la biodiversidad. El objetivo de este estudio fue aislar e identificar las especies de Aspergillus y Penicillium del suelo, en los municipios de Ibimirim y Tupanatinga en el Parque Nacional Catimbau. Cinco colecciones se llevaron a cabo en cada área durante la estación seca de 2012, un total de 25 muestras de suelos por área. Los hongos fueron aislados mediante la suspensión en agua destilada estéril y se sembraron en medio de cultivo Agar Sabouraud más Cloranfenicol y Rosa de Bengala, y también en el medio Agar Dicloran Glicerol. Los aislamientos fueron identificados en el Laboratorio de Colección de Hongos y se confirmaron por secuenciación del espaciador transcrito interno de ADN. Un total de 42 especies fueron identificadas, 22 de ellas pertenecientes al género Aspergillus y 20 al género Penicillium. Los aislamientos de Penicillium mostraron una distribución uniforme en Tupanatinga con índices de uniformidad entre 0.92 y 0.88 en Ibimirim. Entre los aislamientos de Aspergillus el valor encontrado en Tupanatinga (0.85) fue muy similar al encontrado en Ibimirim (0.86). Se observó una gran diversidad y bajo predominio de hongos en las muestras de suelo. Estos resultados contribuyen a la estimación de la diversidad de hongos en ambientes secos, especialmente en la Caatinga, donde la diversidad es decreciente en los suelos que han sufrido alteraciones.

Abstract Soil is a complex biological system that plays a key role for plants and animals, especially in dry forests such as the Caatinga.Fungi from soils, such as Aspergillus and Penicillium, can be used as bioindicators for biodiversity conservation. The aim of this study was to isolate and identify species of Aspergillus and Penicillium in soil, from the municipalities of Tupanatinga and Ibimirim, with dry forests, in the Catimbau National Park. Five collections were performed in each area during the drought season of 2012, totaling 25 soil samples per area. Fungi were isolated by suspending soil samples in sterile distilled water and plating on Sabouraud Agar media plus Chloramphenicol and Rose Bengal, and Glycerol Dicloran Agar. Isolates were identified by morphological taxonomy in the Culture Collection Laboratory and confirmed by sequencing of the Internal Transcribed Spacer of rDNA. A total of 42 species were identified, of which 22 belong to the genus Aspergillus and 20 to Penicillium. Penicillium isolates showed uniform distribution from the collecting area in Tupanatinga, and the evenness indices found were 0.92 and 0.88 in Tupanatinga and Ibimirim, respectively. Among isolates of Aspergillus evenness, the value found in Tupanatinga (0.85) was very close to that found in Ibimirim (0.86). High diversity and low dominance of fungi in soil samples was observed. These results contributed to the estimation of fungal diversity in dry environments of the Caatinga, where diversity is decreasing in soils that have undergone disturbance. Rev. Biol. Trop. 64 (1): 45-53. Epub 2016 March 01.