Cold facts about flower power
The Arabidopsis thaliana, a plant native to Europe, Asia and North Africa, is a popular model organism used by biologists and geneticists because of its small plant genome. It is therefore regularly used to study flowering development. A European project, entitled 'Molecular analysis of the natural variation in vernalisation response of Arabidopsis accessions' (Vernnatvar_at), studied plants' ability to flower or germinate in the spring by exposure to the prolonged cold of winter. A. thaliana has a gene, called 'Flowering locus C' (FLC), which in normal temperatures prevents the plant from flowering. However, after a long cold winter, the gene is suppressed, and the plant is able to flower. Although, the gene has variations in its alleles - DNA sequences of a particular gene. In this case, they can allow the plant to either flower rapidly in one summer, or flower only after vernalisation. The first test carried out by the project was to see whether FLC plays any role in the variation of vernalisation. A type of Arabidopsis thaliana from Sweden called Lov-1 was chosen as a test. The project showed that, after a relatively short vernalisation period, there was a delay in flowering. Further tests on Lov-1 were carried out to determine what part of FLC contributed to the late flowering period. Results showed that a variation within FLC was responsible for the delay which allowed FLC to be activated, and thereby prevent flowering. When delving deeper to discover why FLC had this variation, the researchers found that a specific histone (a protein that regulates genes) associated with repression plays a role: it does not successfully repress FLC to enable flowering in Lov-1. They found that the histone needs twice as much time to suppress FLC as it would in other genes. The project, carried out under a Marie Curie Fellowship, successfully showed that variation within FLC contributes to the natural variation in Arabidopsis thaliana vernalisation. Getting down to the molecular basis of local adaptation in plants is a major goal in genetics, which shows how successful the project was. Therefore, the results obtained from the study show how variation in vernalisation response will have broader impacts on the adaptation of many biological systems, not just Arabidopsis thaliana.