Composition of endophytic fungal community associated with leaves of maize cultivated in south Brazilian field.

The objective of this study was to conduct a survey about fungi associated with leaves from two different maize plant lineages and to analyze their microbiota diversity. Isolated fungi were identified by morphological analysis and molecular taxonomy was performed using ITS1-5.8S-ITS2 rDNA. About 27 fungi morphotypes were obtained, 15 of them were from the first maize lineage. About 86.7% of the individuals belonged to the Dothideomycetes class (Phoma sorghina, Epicocum nigrum, Cladosporium sp., Bipolaris zeicola, and Alternaria alternata complex) and 13.3% to the Sordariomycetes class (Diaporthe/Phomopsis sp. and Nigrospora sp.). This ratio was opposite in the other maize lineage with 25.0% of Dothideomycetes (E. nigrum and Pleosporales) and 75.0% of Sordariomycetes (Gibberella fujikuroi complex, Fusarium graminearum complex, Diaporthe/Phomopsis sp., and Nigrospora sp.). By concerning the analyses of morphological characteristics and molecular phylogeny, this study intended to identify the groups of saprophytic, phytopathogenic, and mycotoxin fungi, which differently co-inhabit leaf tissue of maize plants in both tested lineages.

Analysis of the genetic diversity of Candida isolates obtained from diabetic patients and kidney transplant recipients

Yeasts of the genus Candida have high genetic variability and are the most common opportunistic pathogenic fungi in humans. In this study, we evaluated the genetic diversity among 120 isolates of Candida spp. obtained from diabetic patients, kidney transplant recipients and patients without any immune deficiencies from Paraná state, Brazil. The analysis was performed using the ITS1-5.8S-ITS2 region and a partial sequence of 28S rDNA. In the phylogenetic analysis, we observed a consistent separation of the species C. albicans, C. dubliniensis, C. glabrata, C. tropicalis, C. parapsilosis, C. metapsilosis and C. orthopsilosis, however with low intraspecific variability. In the analysis of the C. albicans species, two clades were formed. Clade A included the largest number of isolates (91.2%) and the majority of isolates from GenBank (71.4%). The phylogenetic analysis showed low intraspecific genetic diversity, and the genetic polymorphisms between C. albicans isolates were similar to genetic divergence found in other studies performed with isolates from Brazil. This low genetic diversity of isolates can be explained by the geographic proximity of the patients evaluated. It was observed that yeast colonisation was highest in renal transplant recipients and diabetic patients and that C. albicans was the species most frequently isolated.

Analysis of the genetic diversity of Candida isolates obtained from diabetic patients and kidney transplant recipients.

Yeasts of the genus Candida have high genetic variability and are the most common opportunistic pathogenic fungi in humans. In this study, we evaluated the genetic diversity among 120 isolates of Candida spp. obtained from diabetic patients, kidney transplant recipients and patients without any immune deficiencies from Paraná state, Brazil. The analysis was performed using the ITS1-5.8S-ITS2 region and a partial sequence of 28S rDNA. In the phylogenetic analysis, we observed a consistent separation of the species C. albicans, C. dubliniensis, C. glabrata, C. tropicalis, C. parapsilosis, C. metapsilosis and C. orthopsilosis, however with low intraspecific variability. In the analysis of the C. albicans species, two clades were formed. Clade A included the largest number of isolates (91.2%) and the majority of isolates from GenBank (71.4%). The phylogenetic analysis showed low intraspecific genetic diversity, and the genetic polymorphisms between C. albicans isolates were similar to genetic divergence found in other studies performed with isolates from Brazil. This low genetic diversity of isolates can be explained by the geographic proximity of the patients evaluated. It was observed that yeast colonisation was highest in renal transplant recipients and diabetic patients and that C. albicans was the species most frequently isolated.

Identification and characterization of endophytic bacteria from corn (Zea mays L.) roots with biotechnological potential in agriculture.

Six endophytic bacteria of corn roots were identified as Bacillus sp. and as Enterobacter sp, by sequencing of the 16S rRNA gene. Four of the strains, CNPSo 2476, CNPSo 2477, CNPSo 2478 and CNPSo 2480 were positive for the nitrogen fixation ability evaluated through the acetylene reduction assay and amplification of nifH gene. Two Bacillus strains (CNPSo 2477 and CNPSo 2478) showed outstanding skills for the production of IAA, siderophores and lytic enzymes, but were not good candidates as growth promoters, because they reduced seed germination. However, the same strains were antagonists against the pathogenic fungi Fusarium verticillioides, Colletotrichum graminicola, Bipolaris maydis and Cercospora zea-maydis. As an indication of favorable bacterial action, Enterobacter sp. CNPSo 2480 and Bacillus sp. CNPSo 2481 increased the root volume by 44% and 39%, respectively, and the seed germination by 47% and 56%, respectively. Therefore, these two strains are good candidates for future testing as biological inoculants for corn.

Genome of Herbaspirillum seropedicae strain SmR1, a specialized diazotrophic endophyte of tropical grasses.

The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme--GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species.

Decolorization and biodegradation of reactive blue 220 textile dye by Lentinus crinitus extracellular extract.

Studies were carried on the decolorization of the textile dye reactive blue 220 (RB220) by a novel isolate of Lentinus crinitus fungi. The optimal conditions for the production of destaining activity were obtained in media containing intermediate concentrations of ammonium oxalate and glucose (10 g L(-1)) as nitrogen and carbon sources, respectively, at 28 degrees C and pH 5.5. Maximum decolorization efficiency against RB220 achieved in this study was around 95%. Ultra-violet and visible (UV-vis) spectrophotometric analyses, before and after decolorization, suggest that decolorization was due to biodegradation. This effect was associated with a putative low molecular weight laccase (41 kDa) displaying good tolerance to a wide range of pH values, salt concentrations and temperatures, suggesting a potential role for this organism in the remediation of real dye containing effluents.

Molecular and morphological markers for rapid distinction between 2 Colletotrichum species.

Endophytic microorganisms reside asymptomatically within plants and are a source of new bioactive products for use in medicine, agriculture, and industry. Colletotrichum (teleomorph Glomerella) is a fungus widely cited in the literature as a producer of antimicrobial substances. Identification at the species level, however, has been a problem in this type of study. Several authors have reported the presence of endophytic fungi from the medicinal plant Maytenus ilicifolia ("espinheira-santa") in Brazil that has antimicrobial activity against various pathogens. Therefore, Colletotrichum strains were isolated from M. ilicifolia and identified based on morphology, RAPD markers, sequence data of the internal transcribed spacer regions (ITS-1 and ITS-2), the 5.8S gene, and species-specific PCR. The analyses suggested the presence of 2 species, Colletotrichum gloeosporioides and Colletotrichum boninense. Two morphological markers were characterized to allow C. gloeosporioides and C. boninense to be distinguished quickly and accurately. The molecular diagnosis of C. boninense was confirmed by using Col1 and ITS4 primers. This species of Colletotrichum is reported for the first time in M. ilicifolia.

Bioprospecting highly diverse endophytic Pestalotiopsis spp. with antibacterial properties from Maytenus ilicifolia, a medicinal plant from Brazil.

Thirteen endophytic fungal strains of the genus Pestalotiopsis were isolated from the medicinal plant Maytenus ilicifolia Mart. ex. Reiss (commonly known as "espinheira santa") and their antimicrobial properties were investigated. Two isolates were successful in inhibiting the growth of the tested microorganisms (Escherichia coli, Klebsiella pneumoniae, Micrococcus luteus, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA)) using the technique of bioautographic thin-layer chromatography (TLC) agar overlay assay. An analysis based on a polyphasic approach integrating taxonomic information, morphological traits, RAPD markers, and the sequencing of the ITS1-5.8S-ITS2 of the rDNA led to the assignment of the isolates as belonging to the species Pestalotiopsis microspora, Pestalotiopsis vismiae, and Pestalotiopsis leucothoes. Therefore, the present study presents a new approach to the study of endophytic fungi of the genus Pestalotiopsis.

Horizontal transfer and hypovirulence associated with double-stranded RNA in Beauveria bassiana.

Beauveria bassiana strains from different hosts and geographic origins were assayed for the presence of double-stranded RNA (dsRNA). Two of them (15.4%) showed extra bands, with approximately 4.0-3.5 kb and 2-0.7 kb, respectively, after electrophoretic separation of undigested nucleic acids. Virus-like particles were approximately 28-30 nm diam. The dsRNA was maintained after conidiogenesis (vertical transmission) and was transmitted horizontally by hyphal anastomosis. Strains purged of dsRNA obtained after cycloheximide treatment showed increased conidial production when compared with strains carrying dsRNA particles. Bioassays demonstrated hypovirulence associated with dsRNA. The mean mortality against the insect Euschistus heros was reduced in strains containing dsRNA when compared with the isogenic dsRNA-free ones.

Pulsed field gel electrophoresis reveals chromosome length and number differences in Brazilian strains of Metarhizium Anisopliae

Cariótipos de oito linhagens selvagens do fungo entomopatogênico Metarhizium anisopliae var. anisopliae foram obtidos em gel, por eletroforese em campo pulsado. As linhagens foram isoladas de insetos provenientes de seis estados brasileiros. As moléculas de DNA cromossômico de três linhagens foram separadas em sete bandas e, de cinco linhagens, em oito bandas. Polimorfismo de tamanho cromossômico também foi observado. O tamanho do DNA cromossômico de todas as linhagens variou de 7,7 a 0,9 Mb, utilizando-se DNA cromossômico de Aspergillus nidulans como padrão. O tamanho do genoma total foi estimado em pelo menos 29,7 Mb. Algumas correlações entre semelhanças e diferenças no cariótipo eletroforético e a ocorrência do ciclo parassexual como também a especificidade com insetos hospedeiros foram discutidas.

RAPD analyses of recombination processes in the entomopathogenic fungus Beauveria bassiana.

To understand the nature of recombination processes in Beauveria bassiana, double-auxotrophic complementary mutant strains were used to produce six heterokaryons by three different methods. Conidia from these heterokaryons were plated on selective media and stable haploid (but not diploid) recombinants were isolated. Single colony recombinants were recovered with both parental and non-parental random amplified polymorphic DNA (RAPD) profiles. These results suggest that a range of different recombination mechanisms may be occurring in B. bassiana.