Abstract
Adaptation to changing environments often requires meaningful phenotypic
modifications to match the current conditions. However, obtaining
information about the surroundings during an organism’s own lifetime may
only permit accommodating relatively late developmental modifications.
Therefore, it may be advantageous to rely on inter-generational or
trans-generational cues that provide information about the environment
as early as possible to allow development along an optimal trajectory.
Transfer of information or resources across generations, known as
parental effects, is well documented in animals and plants but not in
other eukaryotes, such as fungi. Understanding parental effects and
their evolutionary consequences in fungi is of vital importance as they
perform crucial ecosystem functions. In this study, we investigated
whether parental effects are present in the filamentous fungus
Neurospora crassa, how long do they last, are the effects adaptive, and
what is their mechanism. We performed a fully factorial match / mismatch
experiment for a good and poor quality environment, in which we measured
mycelium size of strains that experienced either a matched or mismatched
environment in their previous generation. We found a strong silver spoon
effect in initial mycelium growth, which lasted for one generation, and
increased fitness during competition experiments. By using deletion
mutants that lacked key genes in epigenetic processes, we show that
epigenetic mechanisms are not involved in this effect. Instead, we show
that spore glycogen content, glucose availability and a radical
transcription shift in spores are the main mechanisms behind this
parental effect.