Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Conway, Stephanie [1], Di Stilio, Veronica, S [2].

LEAFY function in the model fern Ceratopteris richardii: reconstructing the ancestral role of a flowering meristem identity gene.

Ferns are an important group of vascular plants that represent both the sister group to seed plants and a midpoint comparison between angiosperms and non-vascular plants. Therefore, an evo-devo approach in ferns has the potential to bridge our understanding of the evolution of form and function in land plants. LEAFY (LFY) is a transcription factor with an important role in the transition from vegetative to floral development in angiosperms. The fact that LFY orthologs are found across non-flowering land plants suggests an important ancestral function beyond flower development. Recent stable transgenesis of the model fern Ceratopteris richardii presents a golden opportunity to examine LFY function in this early-diverging vascular plant. Ontogenetic expression analysis of the two CrLFY genes found that expression peaks in young sporophytes, while promoter-reporter gene activity was more specifically localized to the embryonic shoot apical meristem (SAM) and leaf initials of the compound fern leaf (frond). We generated LFY knockdown mutants using RNAi methods. Preliminary experiments on validated loss-of-function transgenic lines suggest an early phenotype consisting of delayed fertilization and/or delayed zygote development. Sporophytes that did develop had severe leaf abnormalities and persistent gametophytes. Taken together, these results suggest that CrLFY plays a role in the early development of the sporophyte, possibly in the establishment of its SAM, and in the development of the dissected leaf morphology. Based on our results, our working hypothesis is that LFY’s floral meristem identity function was recruited from a broader meristematic role in earlier vascular plants.

1 - University of Washington, Department Of Biology, Po Box 351800, Seattle, WA, 98115-1800, USA
2 - University of Washington, Department Of Biology, Po Box 351800, Seattle, WA, 98115-1800, United States

Keywords:
Ceratopteris richardii
LEAFY
Ferns
meristem
leaf morphology
Evo-devo.

Presentation Type: Oral Paper
Session: 34, Evo-Devo
Location: Sundance 2/Omni Hotel
Date: Wednesday, June 28th, 2017
Time: 9:15 AM
Number: 34006
Abstract ID:408
Candidate for Awards:None