Speaker
Peter Lind
Description
Previous work on the adaptive “wrinkly spreader” (WS) type in
Pseudomonas fluorescens allowed us to develop models and rules to
predict evolutionary outcomes. Knowledge of the genotype-to-
phenotype map of the WS phenotype and of alternative phenotypic
solutions to the problem of air-liquid interface colonization allows
forecasting for related species.
Equipped with the genome sequences of P. protegens and P. syringae
combined with knowledge from work in P. fluorescens, predictions
about the outcome of experimental evolution were made. Phenotypic
predictions were successful in terms of the exopolymeric substances
(EPSs) structural components used to colonize the air-liquid interface
caused by mutational activation of diaguanylate cyclases (DGCs). As
predicted, the most common mutation type was loss-of-function
mutation followed by less common promoter mutations and promoter
capture events. Although up to 39 different DGCs are encoded in these
genomes the relative rates of the top two or four was successfully
predicted. Individual mutations could not be predicted, but the mutated
regions were conserved between species with the majority of mutations
expected to disrupt intermolecular or interdomain interactions.
Mutational hot spots were not conserved between species.
This work shows the potential of extending one of the best-
characterized experimental evolution systems to other species allowing
true testing of evolutionary forecasts. Frequent horizontal gene transfer
and gene loss of DGCs and genes encoding structural EPSs creates a
large diversity among different Pseudomonas species meaning that the
prediction is different for each species. This allows an iterative workflow
of prediction, experimental evolution and model improvement to
explore the limits of evolutionary forecasting. There is potential for
collaborations on many levels including development and testing of
methods for predictions on different biological levels, theoretical
considerations and modelling as well as comparisons with other
experimental systems.
Primary author
Peter Lind
