Cytoplasmic and Evolutionary Genetics
The research group of Dr. Stephan Greiner focuses on molecular and mechanistic aspects of plant evolution and breeding. We concentrate on the role of cytoplasmic genetic elements (the organelle genomes of chloroplasts and mitochondria) in plant adaptation, speciation, and development.
Organelle genomes play an important role in local adaptation of plants to diverse environments. This is exemplified by chloroplast genotype distribution that follows ecological niches shaped by environmental factors such as solar radiation or precipitation. Obviously, environmental changes, for example, resulting from global warming, have huge effects on organelle genome evolution and function.
We are investigating the genetic and physiological consequences of local adaptation of organelles to diverse habitats. Among others, we study chloroplast loci involved in adaptation to arid areas and transfer our findings to crop species like barley. Our chosen model organism - Oenothera (the evening primrose) - allows combining two genetically different chloroplasts in a hybrid plant. This facilitates quick and easy substitution of organelle genomes between species, for example, to test for the adaptive potential of a chloroplast genome in a given environment. This work, however, also uncovered a remarkable contribution of organelle retrograde signalling to plant development, a new field of developmental biology addressed by us. Moreover, in Oenothera, sexual and functionally asexual forms co-occur in overlapping habitats as crossable species. With the aim to develop novel breeding approaches, we elucidate the inheritance mechanism operating in these asexual evening primroses that involves stabilization of heterosis and suppression of homologous recombination in meiosis.