The genetic basis and adaptive significance of pleiotropy: FLC-regulated germination and flowering

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"Phenology", the timing of biological events such as germination and flowering, is one of the most important responses of plants to climate change, and it has been shown to influence performance and local extinctions. Different life stages must respond appropriately to seasonal environmental cues to match their development with the corresponding season. This project seeks to understand how the timing of two crucial phenological events, "germination and flowering" can adapt to seasonal variation even though they share a common genetic basis and must respond differently to similar seasonal environmental cues. Pleiotropy occurs when one gene controls more than one trait. Understanding how multiple traits can adapt when they are controlled by the same genes is a major challenge. Genes in a well known flowering pathway in Arabidopsis thaliana have recently been found to also regulate germination, thereby providing a powerful research system for investigating the genetic basis and adaptive significance of pleiotropy. The major regulator of flowering, FLOWERING LOCUS C (FLC), operates in a pathway that is one of the best characterized molecular pathways of an adaptively significant trait in plants, and it has become a classic system in ecological genetics. It was recently found that the immediate downstream elements in the FLC-flowering pathway also control the germination behavior of seeds, and that natural variation in FLC is associated with natural variation in temperature-dependent germination. This project aims to characterize pleiotropic effects of FLC and other elements in its pathway on both germination and flowering phenology, identify sources of natural variation in FLC-mediated pathways, and measure the fitness consequences of FLC (and FLC-pathway) variation operating through germination and flowering. This research explores the genetic basis of phenology and environmental cuing. As such, the project will provide basic information on how plants respond to environmental change. The project will also generate genomic data and genetic material that will be made available to the research community through The Arabidopsis Information Resource. This project will provide career opportunities and training in molecular genetics and ecological genetics to a postdoc, a graduate student, a research assistant, several undergraduates, and high school students. An educational module will be designed also so that students can explore how genetic pathways influence organismal responses to environmental change.