Molecular basis for three-dimensional elaboration of the Aquilegia petal spur

Yant, Levi; Collani, Silvio; Puzey, Joshua; Levy, Clara; Kramer, Elena M.

Abstract

By enforcing specific pollinator interactions, Aquilegia petal nectar spurs maintain reproductive isolation between species. Spur development is the result of three-dimensional elaboration from a comparatively two-dimensional primordium. Initiated by localized, oriented cell divisions surrounding the incipient nectary, this process creates a pouch that is extended by anisotropic cell elongation. We hypothesized that the development of this evolutionary novelty could be promoted by non-mutually exclusive factors, including (i) prolonged, KNOX-dependent cell fate indeterminacy, (ii) localized organ sculpting and/or (iii) redeployment of hormone-signalling modules. Using cell division markers to guide transcriptome analysis of microdissected spur tissue, we present candidate mechanisms underlying spur outgrowth. We see dynamic expression of factors controlling cell proliferation and hormone signalling, but no evidence of contribution from indeterminacy factors. Transcriptome dynamics point to a novel recruitment event in which auxin-related factors that normally function at the organ margin were co-opted to this central structure. Functional perturbation of the transition between cell division and expansion reveals an unexpected asymmetric component of spur development. These findings indicate that the production of this three-dimensional form is an example of organ sculpting via localized cell division with novel contributions from hormone signalling, rather than a product of prolonged indeterminacy.

Citation

Yant, L., Collani, S., Puzey, J., Levy, C., & Kramer, E. M. (2015). Molecular basis for three-dimensional elaboration of the Aquilegia petal spur. Proceedings of the Royal Society B: Biological Sciences, 282(1803), 1-9. https://doi.org/10.1098/rspb.2014.2778

• Journal Article Type: Article
• Acceptance Date: Jan 13, 2015
• Online Publication Date: Mar 22, 2015
• Publication Date: Mar 22, 2015
• Deposit Date: Mar 8, 2019
• Publicly Available Date: Apr 5, 2019
• Journal: Proceedings of the Royal Society B: Biological Sciences
• Print ISSN: 0962-8452
• Electronic ISSN: 1471-2954
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 282
• Issue: 1803
• Article Number: 20142778
• Pages: 1-9
• DOI: https://doi.org/10.1098/rspb.2014.2778
• Public URL: https://nottingham-repository.worktribe.com/output/1621521
• Publisher URL: https://royalsocietypublishing.org/doi/full/10.1098/rspb.2014.2778
• Contract Date: Mar 8, 2019