Inhibitory activities against rice pathogens of 8-hydroxy-2,4,6-octatriynamide from Agrocybe sp.

8-Hydroxy-2,4,6-octatriynamide, a natural polyacetylene with inhibitory activities against rice pathogens, was isolated from the liquid fermentation broth of strain Agrocybe sp. YB2005 during screening for new natural chemical agents to control rice pathogens. 8-hydroxy-2,4,6-octatriynamide was purified by consecutive chromatography over a Cl8 reversed phase silica gel, sephadex LH-20 and silica gel. The chemical structure of 8-hydroxy-2,4,6-octatriynamide was elucidated through spectroscopic analyses, including 1D- and 2D-NMR, ESI mass spectrometry and X-ray single crystal diffraction. Bioassays showed that 8-hydroxy-2,4,6-octatriynamide could significantly inhibit growth of Xanthomonas oryzae with an MIC of 53.1 µM in a 96-well plate and the growth of Rhizoctonia solani at 1.02 mM in a 24-well plate. When rice leaves were inoculated with Magnaporthe grisea and cultured in artificial nutrition liquid containing 0.34 mM 8-hydroxy-2,4,6-octatriynamide, no rice blast was observed. The present study implied that 8-hydroxy-2,4,6-octatriynamide could be a candidate agent against rice pathogens.

Comparative Analysis of Sporulating and Spore-Deficient Strains of Agrocybe salicacola Based on the Transcriptome Sequences.

The large number of spores produced by edible mushrooms cause many problems, including causing lung disease, depleting natural genetic diversity, and reduced quality of fruiting bodies. Obtaining spore-deficient strains and understanding the underlying molecular mechanisms of such strains are important for breeding work. In this study, we crossed monokaryotic strains isolated from the edible fungi Agrocybe salicacola to obtain three spore-deficient strains with losses of the sterigmata on the surface of the lamella. A mating test revealed that recessive alleles distributed in some strains might control sterigmata development during the mitotic or meiotic phases. Transcriptome analysis revealed that the majority of the genes involved in DNA mismatch repair, base excision repair, and homologous recombination exhibited down-regulated expression patterns in the mutant fruiting bodies. Five genetic fragments, which were highly similar to the GTP-cyclohydrolase encoding gene, the DNA repair gene rad 8, and cell wall integrity and stress response component-encoding genes, were all expressed exclusively in the wild-type strains; these findings provide important information for the study of the spore development of edible fungi.

Evaluación de la producción de cuerpos fructíferos de cepas guatemaltecas del hongo comestible Rukoxil Tunay Che’ (Agrocybe cylindracea (DC. Maire.) en diferentes sustratos / Production of fruiting bodies of Guatemalans strains of the edible mushroom Rukoxil Tunay Che' (Agrocybe cylindracea (DC.) Maire. ) on different substrates

En el presente estudio se determinó la producción de cuerpos fructíferos de cinco cepas nativas de Agrocybe cylindracea sobre tres sustratos y dos tratamientos térmicos, a través del porcentaje de eficiencia biológica y la medición del diámetro de los píleos. Se encontró que el mayor porcentaje de eficiencia biológica de las cepas en los sustratos evaluados fue 115.84 %, que correspondió al sustrato constituido por 29% paja de trigo más 1% de harina de soya pasteurizado y obtenido por la cepa 58.01, la cual también produjo las mayores eficiencias biológicas en todos los sustratos evaluados. Al confrontar el porcentaje de eficiencia biológica en los diferentes sustratos, todas las cepas presentaron valores altos en el sustrato compuesto por 28% de paja de trigo, 1% harina de soya y CaCO3. Con respecto al diámetro de los cuerpos fructíferos, las cepas 58.01, 59.01, 60.01 y 638.08 produjeron píleos menores de 2 cm, entre 2-4 cm y mayores a 4.0 cm en los diferentes sustratos y tratamientos, excepto la cepa 59.01 que en el sustrato formulado con 29% de paja de trigo y 1% de harina de soya, solo produjo cuerpos fructíferos con píleos menores a 2 cm y entre 2-4 cm. En el análisis proximal de los basidiomas de las cepas evaluadas se obtuvo un alto porcentaje de proteínas, fibra cruda y carbohidratos, así como bajo porcentaje de grasas. Se recomienda que en futuras investigaciones o transferencia de tecnología a comunidades o entidades interesadas en el cultivo de este hongo, utilizar paja de trigo suplementada con harina de soya y como regulador de pH CaCO3, ya que en dicho sustrato se obtuvieron los mayores porcentajes de eficiencia biológica para la producción de cuerpos fructíferos de A. cylindracea.

This study determined the production of fruiting bodies of five native strains of Agrocybe cylindracea over three different substrates and two heat treatments, by the biological efficiency percentage and the measurement of diameters of pileus. The major percentage of biological efficiency found from the strains in the evaluated substrates was 115.84%, and corresponded to the substrate formulated by 29% of wheat straw and 1% of pasteurized soy flour, and obtained from the strain 58.01, which also produced the major biological efficiencies in all of the evaluated substrates. When confronting the percentage of biological efficiency in the different substrates, all the strains presented high values in the substrate comprising 28% of wheat straw, 1% of soy flour and CaCO3. In relation to the diameter of the fruiting bodies, the strains 58.01, 59.01, 60.01 and 638.08 produced pileus less than 2 cm, between 2-4 cm and greater than 4 cm in the different substrates and treatments, excepting the strain 59.01 which in the substrate formulated with 29% of wheat straw and 1% of soy flour, only produced fruiting bodies with pileus less than 2 cm and between 2-4 cm. In the chemical proximate analysis of the fruiting bodies of the tested strains, a high percentage of proteins, crude fiber and carbohydrates was obtained, and also a low percentage of fats. For future research or when transferring the technology to communities interested in mushroom cultivation, the utilization of wheat straw supplemented with soy flour and as a regulator of pH CaCO3 is recommended, as in this substrate the highest percentages of biological efficiency for the production of fruiting bodies of A. cylindracea where obtained.

Efficacy of supplementation of selected medicinal mushrooms with inorganic selenium salts.

The aim of the study was to evaluate the possibility of supplementation with inorganic forms of selenium (Na2SeO4 and Na2SeO3) in concentrations of 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 and 1.5 mM of three medicinal mushroom species: Agrocybe aegerita, Hericium erinaceus and Ganoderma lucidum. Tested mushroom species grew in Se additions of 0-0.6 mM (A. aegerita and H. erinaceus), while growth of G. lucidum bodies was observed for 0-0.8 mM. For the latter mushroom species, the total Se content was the highest. Content of Seorg was diverse; for control bodies it was the highest for G. lucidum (only organic forms were present), lower for A. aegerita (84% organic forms) and the lowest for H. erinaceus (56% organic forms). Accumulation of Se(IV) was generally significantly higher than Se(VI) for all tested mushroom species. There was no significant decrease of A. aegerita or G. lucidum biomass with the exception of G. lucidum bodies growing under 0.8 mM of Se species addition (15.51 ± 6.53 g). Biomass of H. erinaceus bodies was the highest under 0.2 (197.04 ± 8.73 g), control (191.80 ± 6.06 g) and 0.1 mM (185.04 ± 8.73 g) of both inorganic salts. The addition to the medium of Se salts brought about macroscopic changes in the fruiting bodies of the examined mushrooms. Concentrations exceeding 0.4 mM caused diminution of carpophores or even their total absence. In addition, colour changes of fruiting bodies were also recorded. At Se concentrations of 0.4 and 0.6 mM, A. aegerita fruiting bodies were distinctly lighter and those of H. erinaceus changed colour from purely white to white-pink.

Opposing developmental functions of Agrocybe aegerita galectin (AAL) during mycelia differentiation.

Mycelia of basidiomycetes differentiating into fruiting body is a controlled developmental process, however the underlying molecular mechanism remains unknown. In previous work, a novel fungal Agrocybe aegerita galectin (AAL) was isolated from A. aegerita in our laboratory. AAL was shown to promote mycelial differentiation in A. aegerita and Auricularia polytricha, indicating that AAL might function as a conserved fruiting initiator during basidiomycete mycelia development. In the current work, we investigate the role of AAL in mycelia differentiation and fruiting body formation. First, the expression and localization of AAL in mycelia, primordium and fruiting body were assessed by Western blotting and immunohistochemistry. AAL was found to be ubiquitously expressed in the primordium and fruiting body but not in the mycelia. AAL facilitated mycelia congregation and promoted fruiting body production when AAL was applied on mycelia. At the same time, when AAL was spread on potato dextrose agar (PDA) medium prior to mycelia inoculation, mycelia exhibited slowed growth rates, resulting in mycelia cords formation and inhibition of fruiting body formation. The 5' regulatory sequence of aal was cloned by 'genome walking'. Here, we show that aal lack introns in the coding region and the upstream 740 bp sequence was characterized by the existence of core promoter elements, which included: two CCAAT boxes (-535/-280), a GC box (-145), a TATA box (-30) and a fungal leader intron within the 5' UTR. The identification of regulatory expression elements may provide an explanation to the stage-specific and high-level expression of aal during fruiting development.

Application of solid waste from anaerobic digestion of poultry litter in Agrocybe aegerita cultivation: mushroom production, lignocellulolytic enzymes activity and substrate utilization.

The degradation and utilization of solid waste (SW) from anaerobic digestion of poultry litter by Agrocybe aegerita was evaluated through mushroom production, loss of organic matter (LOM), lignocellulolytic enzymes activity, lignocellulose degradation and mushroom nutrients content. Among the substrate combinations (SCs) tested, substrates composed of 10-20% SW, 70-80% wheat straw and 10% millet was found to produce the highest mushroom yield (770.5 and 642.9 g per 1.5 kg of substrate). LOM in all SCs tested varied between 8.8 and 48.2%. A. aegerita appears to degrade macromolecule components (0.6-21.8% lignin, 33.1-55.2% cellulose and 14-53.9% hemicellulose) during cultivation on the different SCs. Among the seven extracellular enzymes monitored, laccase, peroxidase and CMCase activities were higher before fruiting; while xylanase showed higher activities after fruiting. A source of carbohydrates (e.g., millet) in the substrate is needed in order to obtain yield and biological efficiency comparable to other commercially cultivated exotic mushrooms.

[Determination of several substrate-decomposition enzyme activities of Agrocybe cylindracea at different stages of development with spectrophotometer].

In the present paper the authors studied the activities of amylase, peroxidase, laccase, protease and cellulase at different developmental stages of agrocybe cylindracea and its mutation with the spectrophotometer. The result showed that the activity of amylase and peroxidase in hyphal stage is the highest for the two basidiomycetes. It can be concluded that these two enzymes are important in vegetative growth stage, but they may have little effect after the appearance of fruit body. The change of their protease is similar: in the hyphal growth stage it is higher than that of mature mushroom. But the activities of laccase and cellulase are very different between the two basidiomycetes. It is obvious that they are some different in physiology and biochemistry.