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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.

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.)

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.)