Metaprofiling of the Bacterial Community in Colonized Compost Extracts by Agaricus subrufescens.

It is well-known that bacteria and fungi play important roles in the relationships between mycelium growth and the formation of fruiting bodies. The sun mushroom, Agaricus subrufescens, was discovered in Brazil ca. 1960 and it has become known worldwide due to its medicinal and nutritional properties. This work evaluated the bacterial community present in mushroom-colonized compost extract (MCCE) prepared from cultivation of A. subrufescens, its dynamics with two different soaking times and the influence of the application of those extracts on the casing layer of a new compost block for A. subrufescens cultivation. MCCEs were prepared through initial submersion of the colonized compost for 1 h or 24 h in water followed by application on casing under semi-controlled conditions. Full-length 16S rRNA genes of 1 h and 24 h soaked MCCE were amplified and sequenced using nanopore technology. Proteobacteria, followed by Firmicutes and Planctomycetes, were found to be the most abundant phyla in both the 1 h and 24 h soaked MCCE. A total of 275 different bacterial species were classified from 1 h soaked MCCE samples and 166 species from 24 h soaked MCCE, indicating a decrease in the bacterial diversity with longer soaking time during the preparation of MCCE. The application of 24 h soaked MCCE provided increases of 25% in biological efficiency, 16% in precociousness, 53% in the number of mushrooms and 40% in mushroom weight compared to control. Further investigation is required to determine strategies to enhance the yield and quality of the agronomic traits in commercial mushroom cultivation.

Influence of the production environment on the cultivation of lettuce and arugula with spent mushroom substrate.

After mushroom production, the substrate plus the cultivated mycelium represents a byproduct, the so-called "spent mushroom substrate" (SMS). We evaluated different SMS types in fresh form, recently taken from the cultivation rooms, for the production of lettuce and arugula in the open field, greenhouse and greenhouse in pot. Three kinds of SMS were used (i - SMS of ABL (Agaricus subrufescens), ii - SMS of POS (Pleurotus ostreatus) and iii - 50% SMS of ABL + 50% SMS of POS) at three doses (1, 2 and 4 kg m-2). For comparison purposes, two commercial soil conditioners, Forth Condicionador® and Visa Fértil Orgânico®, were used. Finally, chicken manure with reference as international organic material was used. A control treatment consisted of a soil plot without any organic material. The application of fresh SMS in the production of LE (lettuce) and AR (arugula) is feasible considering several agronomic parameters evaluated, therefore that in F (field) the superior results were obtained by the ABL dose of 4 kg m-2, in the GR (green house) at a lower dose ABL with 1 kg m-2, POS with 2 kg m-2 and mix with ABL + POS at doses of 2-4 kg m-2, and finally in GR/P (greenhouse pot) it was proved that in a protected environment by rain the combination ABL + POS at dose of 4 kg m-2 is recommended.

Design of a Useful Diagrammatic Scale for the Quantification of Lecanicillium fungicola Disease in Agaricus bisporus Cultivation.

The aim of the research was (i) to evaluate white and cream strains of A. bisporus yields when challenged or not with the pathogen L. fungicola, (ii) to identify the more aggressive pathogen isolates, and (iii) to develop a diagrammatic scale of spot symptoms on infected mushrooms. The experiment was carried out using two strains of A. bisporus (white and cream strains, ABI 19/01 and PB 19/01, respectively) and four isolates of L. fungicola (LF 19/01, FL 19/02, LF 19/03, and LF 19/04). The A. bisporus white strain (ABI 19/01) reached a higher yield of healthy mushrooms compared to the cream strain (PB 19/01) with values of 23.8 and 14.1%, respectively. The LF 19/03 pathogen was most aggressive, reducing the yield of healthy mushrooms by up to 64% for the PB 1/01 strain, and 49.6% for the ABI 19/01 strain. Additionally, for the same isolate, larger mushroom areas were affected, while also displaying symptoms precociously during the second flush. Finally, using the set of visually displayed symptoms assessed in this study, we were able to construct a diagrammatic scale to assist commercial mushroom growers for managing diseased crops.

Low-cost and low maintenance preservation of Agaricus brasiliensis cultures.

Agaricus brasiliensis cultures quickly lose viability when stored at cool temperatures, even for a short period of time. We evaluated several low-cost preservation methods using varied substrates, preservation solutions, and storage temperatures. Agaricus brasiliensis was intolerant to freezing temperatures, making liquid nitrogen use and deep-freezing methods impossible for its preservation. The best preservation conditions for the A. brasiliensis CS1 strain tested in this study were obtained by using rice as substrate and water as preservation solution, with storage at room temperature or when using soil, mushroom cultivation compost, or rice and stored at 10 °C without preservation solution. Those cultures that were reactivated showed the same productivity attributes as the control. In addition, no effect on productivity or biological efficiency was observed through successive subculturing of the strain (CS1). Parboiled rice was successfully used for other A. brasiliensis strains (CS2, CS5, CS7, CS9, and CS10), and also for Pleurotus ostreatus, P. sajor-caju, and Lentinula edodes.