Abstract Detail

Seed-free Plants at the Genomic Scale

Sigel, Erin [1], Schuettpelz, Eric [1], Der, Joshua [2].

Phase-Specific Gene Expression in the Homosporous Fern Polypodium amorphum.

All land plants have life cycles that alternate between multicellular gametophyte and sporophyte phases, but the manifestation of these two generations as independent entities is most extreme in homosporous ferns and lycopods. In these lineages, sporophytes and gametophytes exist as temporally and physically distinct organisms that differ in morphology, physiology, persistence, ecology, and (usually) chromosome number, but share a common genomic composition. Hence, phase-specific morphologies and functions are largely the result of differential gene expression. Here, we present the results of a biologically-replicated, high-throughput transcriptome sequencing experiment in which we compare the gene expression profiles of the gametophyte and sporophyte phases of the homosporous fern, Polypodium amorphum Sukds. Remarkably, only 10% of the approximately 35,000 genes surveyed exhibited significant differences in transcription level between the two phases and less than 3% of genes were found to be expressed in just one of the two phases. We explore the partitioning of expression for particular gene families (e.g., phototropins) between phases and investigate rates of molecular evolution in phase-specific genes. We then discuss how an understanding of phase-specific gene expression in homosporous ferns helps to illuminate the regulatory changes that may have been associated with the shift from gametophyte-dominant to sporophyte-dominant land plant life cycles.

1 - Smithsonian Institution, Department of Botany, P.O. Box 37012, Washington, DC, 20013
2 - California State University, Fullerton, Department of Biological Science, 800 N. State College Blvd., Fullerton, CA, 92831, USA

Keywords:
sporophyte
gametophyte
gene expression
pteridophyte
RNA-seq.

Presentation Type: Colloquium Presentations
Session: C4, Seed Free Plants at the Genomic Scale
Location: Chatham Ballroom - C/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 4:30 PM
Number: C4013
Abstract ID:501
Candidate for Awards:None