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Productive cultivation of the button mushroom (Agaricus bisporus) relies on the use of selective substrates and effective disease management. In extending our previous work on manipulating the developmental microbiome (devome), this study employs the strategy of substrate passaging to explore its effects on crop outcomes and disease dynamics. Here we subjected the casing substrate to ten cycles of passaging. This manipulated substrate stimulated early pinning (primordia formation) by at least three days. Passaged casing also altered disease dynamics when challenged with two commercially important A. bisporus pathogens, Pseudomonas tolaasii (causing bacterial blotch) and Trichoderma aggressivum f. aggressivum (responsible for green mold). Passaged casing had a suppressive effect on blotch disease and a conducive effect on green mold disease. Blotch suppression resulted in a significantly higher yield of asymptomatic mushrooms in all three mushroom harvests (flushes) and in the overall crop yield. Blotch severity was also significantly reduced in passaged casing compared to standard casing due to a lower yield of mushrooms with the highest degree of blotch disease expression. Green mold disease expression was markedly higher in passaged casing, leading to lower numbers of asymptomatic mushrooms. Zones where no growth of hyphae or mushrooms were also observed in passaged casing due to green mold disease pressure. The stimulating effect of passaged casing on mushroom development and the dynamic outcomes for disease challenge from two distinct, commercially damaging diseases, demonstrates the potential for passaged casing to be used as material to study more sustainable mushroom production and disease management practices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Importance: Agaricus bisporus is an economically important edible mushroom and manipulating its developmental patterns is crucial for maximizing yield and quality. One of the potential strategies for achieving such a goal is passaging microbial communities in compost or casing. The current study demonstrated that passaging substrates develop enriched microbial communities, and after a few passages, certain levels of changes in mushroom developmental patterns (the timing of fruiting bodies formation) were observed as well as shifts in the bacterial communities. Overall, a better understanding of the complex interactions between microorganisms present in the cultivation system may help farmers and researchers to develop more efficient and sustainable cultivation practices that can both benefit the environment and human health., Competing Interests: The authors declare no conflict of interest.

The construction industry makes a significant contribution to global CO 2 emissions. Material extraction, processing, and demolition account for most of its environmental impact. As a response, there is an increasing interest in developing and implementing innovative biomaterials that support a circular economy, such as mycelium-based composites. The mycelium is the network of hyphae of fungi. Mycelium-based composites are renewable and biodegradable biomaterials obtained by ceasing mycelial growth on organic substrates, including agricultural waste. Cultivating mycelium-based composites within molds, however, is often wasteful, especially if molds are not reusable or recyclable. Shaping mycelium-based composites using 3D printing can minimize mold waste while allowing intricate forms to be fabricated. In this research, we explore the use of waste cardboard as a substrate for cultivating mycelium-based composites and the development of extrudable mixtures and workflows for 3D-printing mycelium-based components. In this paper, existing research on the use of mycelium-based material in recent 3D printing efforts was reviewed. This review is followed by the MycoPrint experiments that we conducted, and we focus on the main challenges that we faced (i.e., contamination) and the ways in which we addressed them. The results of this research demonstrate the feasibility of using waste cardboard as a substrate for cultivating mycelia and the potential for developing extrudable mixtures and workflows for 3D-printing mycelium-based components., Competing Interests: The authors declare no conflict of interest.

Different from other fungal species that can be largely cultivated in 'axenic conditions' using plant material (e.g., species of Lentinula and Pleurotus in 'sterile' straw-based substrate), the commercial Agaricus bisporus cultivation system relies heavily on ecological relationships with a broad range of microorganisms present in the system (compost and casing). Since the A. bisporus cultivation system consists of a microbial manipulation process, it is important to know the microbial community dynamics during the entire cultivation cycle to design further studies and/or crop management strategies to optimize this system. To capture the bacterial community 'flow' from compost raw materials to the casing to the formation and maturation of mushroom caps, community snapshots were generated by direct DNA recovery (amplicon sequencing). The 'bacterial community flow' revealed that compost, casing and mushrooms represent different niches for bacteria present in the cultivation system, but at the same time, a bacterial exchange between microenvironments can occur for a portion of the community. Within each microenvironment, compost showed intense bacterial populational dynamics, probably due to the environmental changes imposed by composting conditions. In casing, the colonization of A. bisporus appeared, to reshape the native bacterial community which later, with some other members present in compost, becomes the core community in mushroom caps. The current bacterial survey along with previous results provides more cues of specific bacteria groups that can be in association with A. bisporus development and health., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Among the biotic constraints of common mushroom ( Agaricus bisporus ) production, bacterial blotch is considered the most important mushroom disease in terms of global prevalence and economic impact. Etiology and management of bacterial blotch has been a major concern since its original description in 1915. Although Pseudomonas tolaasii is thought to be the main causal agent, various Pseudomonas species, as well as organisms from other genera have been reported to cause blotch symptoms on mushroom caps. In this review, we provide an updated overview on the etiology, epidemiology, and management strategies of bacterial blotch disease. First, diversity of the causal agent(s) and utility of high throughput sequencing-based approaches in the precise characterization and identification of blotch pathogen(s) is explained. Further, due to the limited options for use of conventional pesticides in mushroom farms against blotch pathogen(s), we highlight the role of balanced threshold of relative humidity and temperature in mushroom farms to combat the disease in organic and conventional production. Additionally, we discuss the possibility of the use of biological control agents (either antagonistic mushroom-associated bacterial strains or bacteriophages) for blotch management as one of the sustainable approaches for 21 st century agriculture. Finally, we aim to elucidate the association of mushroom microbiome in cap development and productivity on one hand, and blotch incidence/outbreaks on the other hand.

Aims: To investigate characterization of the bacterial community composition and functionality and their impact on substrate biodegradation as well as mushroom yield., Methods and Results: Bacterial diversity, composition and functionality were accessed by DNA-derived analysis for a sugarcane straw-based substrate composted for either 5, 10 or 15 days. In addition, carbon and nitrogen losses, carbohydrate conversion and mushroom yields were measured for the different treatments. Changes were observed in the bacterial community diversity and composition after the process started, but not during the composting process itself. Following phase I, Acinetobacter sequences were recovered in high numbers, and selected genes associated with nitrogen metabolism and lignocellulose deconstruction were mapped. Substrate physicochemical composition showed elevated carbon and nitrogen losses after 10 and 15 days of phase I with reductions in mushroom yield., Conclusions: Acinetobacter species appear to play an important role in substrate degradation processes, and a 5-day phase I period showed a significant higher mushroom yield compared to composting for either 10 or 15 days., Significance and Impact of the Study: This study confers a better understanding of the bacterial community manipulation during the substrate preparation and their influence in substrate selectivity for the Pleurotus ostreatus cultivation., (© 2018 The Society for Applied Microbiology.)

Substrate preparation (i.e., composting) for Agaricus bisporus cultivation is the most critical point of mushroom production. Among many factors involved in the composting process, the microbial ecology of the system is the underlying drive of composting and can be influenced by composting management techniques. Pasteurization temperature at the beginning of phase II, in theory, may influence the bacterial community and subsequently the "selectivity" and nutrition of the final substrate. Therefore, this hypothesis was tested by simulation in bioreactors under different pasteurization conditions (57 °C/6 h, 60 °C/2 h, and 68 °C/2 h), simulating conditions adopted by many producers. Bacterial diversity, based on 16S ribosomal RNA obtained by high-throughput sequencing and classified in operational taxonomic units (OTUs), was greater than previously reported using culture-dependent methods. Alpha diversity estimators show a lower diversity of OTUs under a high-temperature pasteurization condition. Bacillales order shows a relatively higher OTU abundance under a high-pasteurization temperature, which also was related to high ammonia emission measurements. On the other hand, beta diversity analysis showed no significantly changes in the bacterial community structure under different conditions. Agaricus bisporus mycelium growth during a standard spawn run period was significantly slower in the compost pasteurized at high temperature. Since the bacterial community structure was not greatly affected by different pasteurization conditions but by-products left (e.g., ammonia) at the end of compost conditioning varied, further studies need to be conducted to determine the functional role of the microbial communities found during substrate preparation for Agaricus bisporus cultivation.