Strain instability in fungi as a model for the study of recombination and epigenetic regulation of meiosis.
Technological developments of the last 4 decades have propelled the global mushroom production from less than 1 million to almost 8 million tonnes of mushrooms, with a combined economic value of about $58 billion (Royse, D. J., et al., 2016). Key to this entire mushroom industry is the continuous vegetative propagation of tiny single colonies of selected stock cultures, into very large volumes of colonized and mushroom producing substrates. Occurrence of phenotypic instability in fungal strains has become of increasing concern; larger scales and centralized strain production suffer increasing economic damage in case of strain instabilities. Morphological abnormalities in fungi that occur in any given stage of the mushroom life cycle imply that fungi possess an inherent ability to become instable. Instability associated phenotypes persist during further sub-culturing, suggesting that certain genetic, recombination, and or epigenetic changes are involved. We assembled a chain-wide consortium to address the problem of phenotypic expression of strain instabilities in each step of the fungal life cycle, and in relation to mushroom production. This project will generate the primary scientific base for a model to study the detailed biological mechanisms behind genetic instabilities in fungi and related processes in other organisms. Testing of stress and cultivation conditions, extensive phenotyping, new phenotyping protocols and in-depth whole genome analyses will provide new information on causes of fungal strain instability. This is vital to adopt measures to detect, reduce or prevent strain instability incidences in the mushroom industry. Mushroom forming fungi are multicellular and undergo complex morphogenetic developments, yet have small genomes and brief life cycles. The small genomes, short life cycles and whole genome sequencing (including epigenetic analysis) at low costs make these fungi an ideal model to study the relation between genome instability and phenotypic aberrations. The outcomes can be relevant for similar symptoms seen in plants and animals, including human diseases.
a) classify the main strain instabilities in the mushroom industry and determine if they are vegetatively stable and or inheritable, b) identify (epi)genetic changes that correlate with observed instability phenotypes, c) determine environmental (stress) factors that can trigger strain instability, d) develop with these results a basic model to study causes and mechanisms of (epi)genetic (in)stabilities in mushroom forming fungi and other organisms.
The four (2.2, a-d) aspects will be the basis for future breeding, development of more stable strains, and screening methods to detect instability in mother cultures.
a) accurate definitions of various strain instabilities in the mushroom industry, b) identified strain instabilities that are vegetatively stable and or inheritable, c) identified (epi)genetic factors that correlate with instability phenotypes, d) knowledge about which environmental (stress) factors trigger strain instability, e) a basic model that explains strain instabilities and enables further studies on causes and mechanisms of (epi)genetic (in)stabilities in mushroom forming fungi and other organisms.