Molekylærgenetisk karakterisering av vernaliseringsrespons i PACMAD-gras

Abstract

Many plants rely on a mechanism called vernalisation response to match reproductive output with favourable environmental conditions. This trait is an important adaptation to seasonal climates, like for example at high latitudes. In grasses (Poaceae), evolution of seasonally-cued flowering was one of the traits enabling certain lineages to move out of their tropical origins and diversify in temperate zones. Due to its ecological and agricultural importance, the genetic basis of vernalisa- tion response is particularly well-studied in Pooideae grasses that predominates temperate habit- ats. However, little is known about vernalisation systems in other grass lineages that are adapted to cool and seasonal climates. In this study, I ask whether vernalisation response is found in a grass lineage called the pacmad clade. To disentangle the molecular machinery governing this trait, I quantified the expression of two paralogous FRUITFULL-like (FUL-like) vernalisation genes. My results demonstrate that vernalisation response is widespread in pacmad grasses, and found in at least four subfamilies with temperate representatives. Moreover, I found evidence for the co- option of a novel vernalisation gene (FUL2) into the vernalisation gene network Arundinoideae species Molinia caerulea.