Morels: Physiology, Genetics, and Interactions With the Environment

Commonly known as morels, species of Morchella are important gourmet mushrooms in Ascomycota. Morchella rufobrunnea (the so-called red-blushing morel) and species of black morels in the Elata clade of genus Morchella were once only wild-foraged, but have been domesticated to artificially farming systems in recent decades. Artificial cultivation of M. rufobrunnea in indoor chambers was successfully reported in the United States and Israel. Large-scale cultivation of black morels had become feasible in China after the breeding of several high-yield varieties in combination with the development and widespread application of an appropriate organic substrate contained in the so-called exogenous nutrient bag. Exogenous nutrient bags are placed on the soil surface of a soil bed colonized with morel mycelium and offer a carbon source for the growth and fruiting of black morels. Since morels were first successfully cultivated commercially in Sichuan a decade ago, morel cultivation has expanded to more than 20 provinces in China, as well as a few temperate regions around the world. However, the yield obtained is often unstable, making morel cultivation a high-profit but high-risk industry. While the practice of morel cultivation is more empirical than rationally designed, our basic knowledge of morel biology is still a puzzle with many missing pieces. Key ecophysiological and metabolic mechanisms triggering morel fruiting need more detailed understanding.

Morchella species possess diverse ecologies, including saprotrophic and biotrophic nutrition modes. Artificial cultivation of black morels is an outdoor-soil ecosystem dominated by natural microbes, rather than quasi-sterile substrates routinely used for typical wood-decaying fungi such as oyster mushroom and shitake. Therefore, the growth and fruiting of morels are complex and rely on the physiological status of the morel mycelial network in combination with soil physiochemical factors and microbiota in the mycosphere. Studies are needed that combine interdisciplinary research toolkits - from fungal genetics, developmental biology, functional multi-omics, biochemistry, and soil science, to microbial ecology.

We welcome the submission of original research, reviews, methods, and perspectives on “Morels: physiology, genetics, and interactions with the environment”. The potential topics may include, but are not limited to:

- Mechanisms driving the transition of morels from vegetative growth to reproductive growth.
- C and N fluxes during growth and fruiting of morels.
- Nutrients that are required for the growth and fruiting of morels.
- Mechanism of morels to mineralize, solubilize, and assimilate N, P, and S from soil organic and inorganic fractions.
- Interactions between morels and the biotic and abiotic factors in the soil environment.
- Mycorrhizal morels (e.g., the Esculenta clade) and the interactions with their host plants.
- Growth-promoting or pathogenic microorganisms associated with morel cultivation.
- Genetic, molecular, metabolic, and cellular mechanisms affecting the vitality, degeneration, and fruiting capacity of morel cultures.
- Report of new germplasm resource of morels with genetic analysis.