Manipulating Agaricus bisporus developmental patterns by passaging microbial communities in complex substrates.

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.

Three-Dimensional Printing of Living Mycelium-Based Composites: Material Compositions, Workflows, and Ways to Mitigate Contamination.

The construction industry makes a significant contribution to global CO2 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.

100 Years Since Tolaas: Bacterial Blotch of Mushrooms in the 21st Century.

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 21st 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.