RESUMO
Finding causal relationships between genotypic and phenotypic variation is a key focus of evolutionary biology, human genetics and plant breeding. To identify genome-wide patterns underlying trait diversity, we assembled a high-quality reference genome of Cardamine hirsuta, a close relative of the model plant Arabidopsis thaliana. We combined comparative genome and transcriptome analyses with the experimental tools available in C. hirsuta to investigate gene function and phenotypic diversification. Our findings highlight the prevalent role of transcription factors and tandem gene duplications in morphological evolution. We identified a specific role for the transcriptional regulators PLETHORA5/7 in shaping leaf diversity and link tandem gene duplication with differential gene expression in the explosive seed pod of C. hirsuta. Our work highlights the value of comparative approaches in genetically tractable species to understand the genetic basis for evolutionary change.
Assuntos
Cardamine/genética , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Evolução Biológica , Cardamine/anatomia & histologia , Duplicação Gênica , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Leaves show considerable variation in shape, and may be described as simple, when the leaf is entire, or dissected, when the leaf is divided into individual leaflets. Here, we report that the SIMPLE LEAF3 (SIL3) gene is a novel determinant of leaf shape in Cardamine hirsuta - a dissected-leaved relative of the simple-leaved model species Arabidopsis thaliana. We show that SIL3 is required for leaf growth and leaflet formation but leaf initiation is less sensitive to perturbation of SIL3 activity. SIL3 is further required for KNOX (knotted1-like homeobox) gene expression and localized auxin activity maxima, both of which are known to promote leaflet formation. We cloned SIL3 and showed that it encodes RLI2 (RNase L inhibitor 2), an ATP binding cassette-type ATPase with important roles in ribosome recycling and translation termination that are conserved in eukaryotes and archaea. RLI mutants have not been described in plants to date, and this paper highlights the potential of genetic studies in C. hirsuta to uncover novel gene functions. Our data indicate that leaflet development is sensitive to perturbation of RLI2-dependent aspects of cellular growth, and link ribosome function with dissected-leaf development.