Laura M. Paiva

Richness of endophytic fungi isolated from Opuntia ficus-indica Mill. (Cactaceae) and preliminary screening for enzyme production

Opuntia ficus-indica Mill. (forage cactus) is farmed with relative success in the semi-arid region of the Brazilian northeast for commercial purposes, particularly as forage and food. Endophytic microorganisms are those that can be isolated inside plant tissues and can be a new source to production of enzymes with different potentialities. The objective of this study was to describe the richness of endophytic fungi from O. ficus-indica and to detect the capacity of these species to produce extracellular hydrolytic enzymes. Forty-four endophytic fungi species were isolated. Among them, the most commonly found were Cladosporium cladosporioides (20.43%) and C. sphaerospermum (15.99%). Acremonium terricola,Monodictys castaneae, Penicillium glandicola, Phoma tropica and Tetraploa aristata are being reported for the first time as endophytic fungi for Brazil. The majority of isolated fungi exhibited enzymatic potential. Aspergillus japonicus and P. glandicola presented pectinolytic activity. Xylaria sp. was the most important among the other 14 species with positive cellulase activity. All 24 isolates analysed were xylanase-positive. Protease was best produced by isolate PF103. The results indicate that there is a significant richness of endophytic fungi in O. ficus-indica, and that these isolates indicate promising potential for deployment in biotechnological processes involving production of pectinases, cellulases, xylanases and proteases.

Endophytic fungi from medicinal plant Bauhinia forficata: Diversity and biotechnological potential

Bauhinia forficata is native to South America and used with relative success in the folk medicine in Brazil. The diversity, antibacterial activity, and extracellular hydrolytic enzymes of endophytic fungi associated with this plant were studied. Plant samples, which included leaves, sepals, stems, and seeds, were used. Ninety-five endophytic fungal were isolated (18 from leaves, 22 from sepals, 46 from stems, and nine from seeds), comprising 28 species. The most frequently isolated species were Acremonium curvulum (9.5%), Aspergillus ochraceus (7.37%), Gibberella fujikuroi (10.53%), Myrothecium verrucaria (10.53%) and Trichoderma piluliferum (7.37%). Diversity and species richness were higher in stem tissues, and Sorensen’s index of similarity between the tissues was low. Eleven fungi showed antibacterial activity. Aspergillus ochraceus , Gibberella baccata , Penicillium commune , and P. glabrum were those with the greatest antibacterial activity against Staphylococcus aureus and/or Streptococcus pyogenes . Thirteen species showed proteolytic activity, particularly Phoma putaminum . Fourteen species were cellulase positive, particularly the Penicillium species and Myrmecridium schulzeri . All isolates tested were xylanase positive and 10 showed lipolytic activity, especially Penicillium glabrum . It is clear that the endophytic fungi from B. forficata have potential for the production of bioactive compounds and may be a source of new therapeutic agents for the effective treatment of diseases in humans, other animals, and plants. To our knowledge, this is the first study of endophytic fungi from different tissues of B. forficata and their biotechnological potential.

Bezerromycetales and Wiesneriomycetales ord. nov. (class Dothideomycetes), with two novel genera to accommodate endophytic fungi from Brazilian cactus

During a survey of endophytic fungi from the cactus Tacinga inamoena in a Brazilian tropical dry forest (Caatinga) some undescribed ascomycetous fungi were isolated. These fungi are characterized by superficial and immersed, globose to subglobose, smooth or hairy ascomata, bitunicate asci, and muriformly septate, ellipsoidal ascospores. Multigene phylogenetic analyses using sequences from partial ITS, SSU and LSU nrDNA and the translation elongation factor 1-alpha gene (tef1) demonstrated a monophyletic clade accommodating these endophytic fungi in the class Dothideomycetes, closely related to the order Tubeufiales. Based on morphological features and phylogenetic analyses, these fungi could not be placed in the order Tubeufiales, in the new order Wiesneriomycetales, or any other known genus in the class Dothideomycetes. Thus, two new genera (Bezerromyces, with B. brasiliensis and B. pernambucoensis, and Xiliomyces with X. brasiliensis), a new family (Bezerromycetaceae) and a new order (Bezerromycetales) are introduced to accommodate these novel taxa. Our phylogenetic analyses also demonstrated that the clade accommodating Wiesneriomycetaceae represents a new order, here introduced as Wiesneriomycetales.

Isolamento e seleção de fungos filamentosos do solo de sistemas agroflorestais do Município de Bom Jardim (PE) com base na capacidade de produção de enzimas hidrolíticas

This study aimed to isolate and identify fungi from soil of agroforestry systems and to evaluate the enzymatic activity of these fungi. These were isolated by successive dilution technique and evaluated for their ability to degrade starch, cellulose and caseine. Eleven species of anamorph fungi (Hyphomycetes) distributed in five genera were identified: Aspergillus, Cladosporium, Curvularia, Fusarium and Penicillium. The species studied did not show satisfactory amylolytic activity. Cladosporium cladosporioides (Fres.) De Vries and Penicillium chrysogenum Thom had higher enzyme relation index (ERI) for protease and cellulase. Among the species studied six showed higher Relative Enzymatic Index (IRE) for cellulase in comparison to the other enzymes.

MORPHOLOGICAL, CYTOLOGICAL, AND CULTURAL ASPECTS OF CURVULARIA PALLESCENS

Curvularia pallescens Boedijn (Hyphomycetes) is redescribed with the aid of a scanning electron microscope, and the optimal cultural conditions for growing this fungus are discussed. Cytological analysis and nuclear condition, observed through the HCl-Giemsa technique, showed vegetative and reproductive structures (hypha and conidia) formed by uni, bi, tri, and multinucleated segments. Cultures of C. pallescens in Complete medium and in Potato dextrose agar varied on growth, on aspects of the border of the colonies and also on medium pigmentation. The Complete medium and the temperature between 25-28°C were the most indicated for growth of C. pallescens.

New endophytic Toxicocladosporium species from cacti in Brazil, and description of Neocladosporium gen. nov.

Brazil harbours a unique ecosystem, the Caatinga, which belongs to the tropical dry forest biome. This region has an important diversity of organisms, and recently several new fungal species have been described from different hosts and substrates within it. During a survey of fungal endophyte diversity from cacti in this forest, we isolated cladosporium-like fungi that were subjected to morphological and multigene phylogenetic analyses including actA, ITS, LSU, rpb2 and tub2 gene sequences. Based on these analyses we identified two new species belonging to the genus Toxicocladosporium, described here as T. cacti and T. immaculatum spp. nov., isolated from Pilosocereus gounellei subsp. gounellei and Melocactus zehntneri, respectively. To improve the species recognition and assess species diversity in Toxicocladosporium we studied all ex-type strains of the genus, for which actA, rpb2 and tub2 barcodes were also generated. After phylogenetic reconstruction using five loci, we differentiated 13 species in the genus. Toxicocladosporium velox and T. chlamydosporum are synonymized based on their phylogenetic position and limited number of unique nucleotide differences. Six strains previously assigned to T. leucadendri, including the ex-type strain (CBS 131317) of that species, were found to belong to an undescribed genus here named as Neocladosporium gen. nov., with N. leucadendri comb. nov. as type species. Furthermore, this study proposes the actA, ITS, rpb2 and tub2 as main phylogenetic loci to recognise Toxicocladosporium species.

Pathogenicity of Beauveria bassiana and production of cuticle-degrading enzymes in the presence of Diatraea saccharalis cuticle

The sugarcane borer, Diatraea saccharalis , is one of the worst pests in Brazilian sugarcane crop, causing high levels of financial losses every year. Beauveria bassiana is an entomopathogenic fungus widely used in the biological control of several agricultural pests. The aims of this study were to: (1) evaluate the pathogenicity of B. bassiana strains against D. saccharalis (2) investigate the production of proteases and chitinase by B. bassiana in the presence of the cuticle of sugarcane borer; and, (3) evaluate the relation between the production of enzymes and pathogenicity of the strains. All isolates tested were pathogenic to D. saccharalis and the mortality ranged from 36 to 88%. The production of enzymes was higher in the medium containing cuticle, showing that the process is stimulated by specific components found in the cuticle of the host. Pr1 activity was higher than Pr2 and both were produced at 24 h. The highest production of chitinase was obtained at 96 h of culture for all strains tested. Levels of specific cuticle-degrading enzymes such as proteases correlated positively with specific virulence parameters. B. bassiana URM2915 showed promising features to be used in a biological control program of D. saccharalis . Key words : Biological control, sugarcane, subtilisin-like protease, trypsin-like protease, chitinase.

Mycological Diversity Description I

Here, Quambalaria fabacearum and Neopestalotiopsis brasiliensis are introduced as new species from Brazil, isolated as endophyte from Mimosa tenuiflora and causing post-harvest rot disease on fruits of Psidium guajava, respectively. Diaporthe inconspicua is emended to include a more detailed morphological description. Neopestalotiopsis egyptiaca is reported as new to the Americas and as causing post-harvest rot disease on fruits of Psidium guajava, while Umbelopsis isabellina is reported as endophyte.

Requalification of a Brazilian Trichoderma Collection and Screening of Its Capability to Decolourise Real Textile Effluent

Water contamination with large amounts of industrial textile coloured effluents is an environmental concern. For the treatment of textile effluents, white-rot fungi have received extensive attention due to their powerful capability to produce oxidative (e.g., ligninolytic) enzymes. In addition, other groups of fungi, such as species of Aspergillus and Trichoderma, have also been used for textile effluents treatment. The main aim of the present study was to requalify a Brazilian Trichoderma culture collection of 51 Trichoderma strains, isolated from different sources in Brazil and preserved in the oldest Latin-American Fungal Service Culture Collection, The Micoteca URM WDCM 804 (Recife, Brazil). Fungal isolates were re-identified through a polyphasic approach including macro- and micro-morphology and molecular biology, and screened for their capability to decolourise real effluents collected directly from storage tanks of a textile manufacture. Trichoderma atroviride URM 4950 presented the best performance on the dye decolourisation in real textile effluent and can be considered in a scale-up process at industrial level. Overall, the potential of Trichoderma strains in decolourising real textile dye present in textile effluent and the production of the oxidative enzymes Lac, LiP and MnP was demonstrated. Fungal strains are available in the collection e-catalogue to be further explored from the biotechnological point of view.