The evolution of inflorescence diversity in the nightshades and heterochrony during meristem maturation

Lemmon, Z. H., Park, S. J., Jiang, K., Van Eck, J., Schatz, M. C., Lippman, Z. B. (2016) The evolution of inflorescence diversity in the nightshades and heterochrony during meristem maturation. Genome Res, 26 (12). pp. 1676-1686. ISSN 1549-5469 (Electronic)1088-9051 (Linking)

URL: https://www.ncbi.nlm.nih.gov/pubmed/27821409
DOI: 10.1101/gr.207837.116

Abstract

One of the most remarkable manifestations of plant evolution is the diversity for floral branching systems. These "inflorescences" arise from stem cell populations in shoot meristems that mature gradually to reproductive states in response to environmental and endogenous signals. The morphology of the shoot meristem maturation process is conserved across distantly related plants, raising the question of how diverse inflorescence architectures arise from seemingly common maturation programs. In tomato and related nightshades (Solanaceae), inflorescences range from solitary flowers to highly branched structures bearing hundreds of flowers. Since reproductive barriers between even closely related Solanaceae have precluded a genetic dissection, we captured and compared meristem maturation transcriptomes from five domesticated and wild species reflecting the evolutionary continuum of inflorescence complexity. We find these divergent species share hundreds of dynamically expressed genes, enriched for transcription factors. Meristem stages are defined by distinct molecular states and point to modified maturation schedules underlying architectural variation. These modified schedules are marked by a peak of transcriptome expression divergence during the reproductive transition, driven by heterochronic shifts of dynamic genes, including transcriptional regulators with known roles in flowering. Thus, evolutionary diversity in Solanaceae inflorescence complexity is determined by subtle modifications of transcriptional programs during a critical transitional window of meristem maturation, which we propose underlies similar cases of plant architectural variation. More broadly, our findings parallel the recently described transcriptome "inverse hourglass" model for animal embryogenesis, suggesting both plant and animal morphological variation is guided by a mid-development period of transcriptome divergence.

Item Type: Paper
Subjects: organs, tissues, organelles, cell types and functions > tissues types and functions > inflorescence
organs, tissues, organelles, cell types and functions > tissues types and functions > meristem
organism description > plant > tomato
CSHL Authors:
Communities: CSHL labs > Lippman lab
CSHL labs > Schatz lab
Depositing User: Matt Covey
Date Deposited: 14 Nov 2016 21:47
Last Modified: 07 Sep 2017 15:49
PMCID: PMC5131819
Related URLs:
Dataset ID:
URI: http://repository.cshl.edu/id/eprint/33884

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