Transformation of Compatible Mating-Type Genes in Monokaryons Triggers Fruiting Body Development by Activating Mating Pathways in Pleurotus eryngii

Fruiting body formation is the most important developmental event in the edible mushroom life cycle; however, the genetic regulation of this process is not well understood. Pleurotus eryngii is a widely cultivated mushroom with high economic value. The mating of two monokaryons carrying compatible A and B mating-type genes is required for the development of fruiting bodies in P. eryngii. In this study, we showed that the monokaryons of P. eryngii transformed with compatible homeodomain (A mating type) and pheromone (B mating type) genes can complete fruiting body development but cannot form basidiospores. Transcriptional analyses revealed that expression of endogenous homeodomain and pheromone receptor genes and mating signaling pathways were activated by transferred homeodomain and pheromone genes in the transformants. Our findings provide a novel model for studying fruiting body development, which may accelerate the genetic breeding of edible mushrooms in the future. IMPORTANCE Fruiting bodies of edible mushrooms have high nutritional value. However, the fruiting body development of mushrooms is not well understood, and thus, many wild edible mushrooms of economic importance cannot be cultivated artificially. Moreover, variety among cultivatable mushrooms has improved marginally. Under natural conditions, fruiting body development can be initiated only in a dikaryon, the sexual mycelium obtained from mating two compatible monokaryons. The present work showed induction of fruiting body development in Pleurotus eryngii monokaryons by genetic manipulation. Gene expression analyses revealed key genes and signaling pathways involved in the fruiting body development of P. eryngii.