Towards more resilient and versatile mushroom production by mixed cultivation

Besides humans, who cultivate mushrooms such as the button mushroom Agaricus bisporus, also insects such as fungus-growing termites cultivate fungi (Termitomyces spp.) for food. Even though these fungi have been domesticated independently and at very different times, they are both cultivated in large-scale monocultures. Although monoculture cultivation results in higher yield than mixed cultivation, monoculture has a major drawback: the single strain cultivated needs to be a ‘jack-of-all-trades’. It must break down its growth substrate and also convert it into high-quality mushrooms. A mixed-cultivation mode would be highly desirable, since breeding different strains with different specialisations, could give a more resilient and versatile production system with regional and/or resistant varieties being grafted onto a universal ‘rootstock’ strain bred for optimized compost break down. However, the development of mixed culture is hindered by highly precise self/non-self-recognition systems (allorecognition), preventing hyphal fusion and leading to antagonism between different cultivars reducing yield. In this proposal we unravel the genetics and molecular and physiological consequences of allorecognition in the button mushroom and the termite fungus. By comparing those two convergent systems, we determine whether similar genes underlie allorecognition, if mixed cultivation gives similar problems in both systems, and how such allorecognition problems can be overcome. By charting the specifics and communalities of the two systems of fungal cultivation we ultimately aim to achieve a mixed-cultivation system for the button mushroom.