reproductive isolation; pollination; sexually deceptive orchids; next-generation sequencing; barrier genes; candidate genes; ecological speciation; orchids; evolution; speciation; selection; reproductive barriers; molecular biology; transcriptomics
Sedeek Khalid E. M., Whittle Edward, Guthörl Daniela, Grossniklaus Ueli, Shanklin John, Schlüter Philipp M. (2016), Amino acid change in an orchid desaturase enables mimicry of the pollinator’s sex pheromone, in Current Biology
, 26, 1505-1511.
Xu Shuqing, Schlüter Philipp (2015), Modeling the two-locus architecture of divergent pollinator adaptation: how variation in SAD paralogs affects fitness and evolutionary divergence in sexually deceptive orchids, in Ecology and Evolution
, 5(2), 493-502.
Sedeek Khalid E. M., Qi Weihong, Schauer Monica A., Gupta Alok K., Poveda Lucy, Xu Shuqing, Liu Zhong-Jian, Grossniklaus Ueli, Schiestl Florian P., Schlüter Philipp M. (2013), Transcriptome and proteome data reveal candidate genes for pollinator attraction in sexually deceptive orchids, in PLoS One
, 8(5), e64621.
Xu Shuqing, Schlüter Philipp M., Grossniklaus Ueli, Schiestl Florian P. (2012), The genetic basis of pollinator adaptation in a sexually deceptive orchid, in PLoS Genetics
, 8(8), e1002889.
Sedeek Khalid E. M., Scopece Giovanni, Staedler Yannick M., Schönenberger Jürg, Cozzolino Salvatore, Schiestl Florian P., Schlüter Philipp M., Genic rather than genome-wide differences between sexually deceptive Ophrys orchids with different pollinators, in Molecular Ecology
Sexually deceptive orchids mimic the mating signals of their pollinator females to attract male pollinators. These orchids have an unusually high specificity of pollination resulting in strong reproductive isolation exerted by their pollinators. In this system, pollinator shifts can lead to the establishment of floral (reproductive) isolation as the first step towards ecological speciation. Floral traits involved in pollinator attraction can therefore be implicated in the evolution and maintenance of reproductive isolation in these non-model organisms. Likewise, genes underlying these phenotypic traits can be implicated in the genetic barrier isolating different species. This project seeks to (1) identify and (2) functionally characterise genes underlying adaptive floral traits, particularly traits underlying floral isolation and specific pollinator attraction, in the sexually deceptive orchid genus Ophrys. This interdisciplinary project, bridging molecular biology and pollination ecology, will deepen our understanding of the molecular mechanisms underlying species differentiation and floral isolation by combining the strengths of genomics technology and molecular biology with a study system in which a wealth of pollination data are available.This project aims at uncovering the genes and molecular mechanisms that are involved in establishing or maintaining pollinator-mediated reproductive isolation among closely related orchid species. Specifically, we will:(1a) create floral reference transcriptomes by 454 next-generation sequencing,(1b) compare gene expression among species by RNA-Seq using SOLiD next-generation sequencing,(1c) identify candidate genes by combining data on sequence divergence, expression differences, and annotations of putative gene function,(2a) validate candidate genes by testing the association between floral phenotypes and candidate gene sequence and/or expression both in natural populations and during floral development,(2b) investigate candidate gene function by gene silencing and in transgenic Arabidopsis plants,(2c) reconstruct the candidate genes’ evolutionary history and test for the signatures of selection.These analyses will be informative of the molecular mechanisms that affect phenotypic traits, and of how selection imposed by the environment results in genetic change. Results from this project will further our knowledge of the molecular or developmental constraints acting on trait evolution, and will help us understand how barriers to gene flow may be built up in terms of gene function. Our results will therefore be relevant for understanding the pace of adaptation and speciation in plants where reproduction is closely tied to pollinator behaviour.