ABSTRACT
Investigating the evolution of complex phenotypes and the underlying molecular bases of their variation is critical to understand how organisms adapt to the environment. We used leaf growth as a model trait as it is highly integrative of internal and external cues and relies on functions at different levels of the plant organization. Applying classical quantitative genetics on a recombinant inbred line population derived from a Can-0 x Col-0 cross, we identified the MADS-box transcription factor FLOWERING LOCUS M (FLM) as a player of the phenotypic variation for leaf growth and colour. Interestingly, we showed that allelic variation at FLM modulates plant growth strategy along the leaf economics spectrum, a trade-off between resource acquisition and resource conservation observable across thousands of plant species. We demonstrated that the functional differences at FLM relies on a single intronic substitution, disturbing transcript splicing and leading to a low expression of the active FLM transcript. Using phenotypic and climatic data across Arabidopsis natural populations, our work shows how noncoding genetic variation of a single gene may be adaptive through synergistic pleiotropy.
