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Abstract Detail

Recent Topics Posters

Groffman, Dominique J [1], Zumajo, Cecilia [2], Ambrose, Barbara [3].

Evolution of the SPOROCYTELESS (SPL) Gene Lineage: Reproductive Development of Early Land Plant Sporangia.

SPOROCYTELESS (SPL; NOZZLE) belongs to the recently characterized SPL/SPEAR (SPR) transcription factor family, identifiable by an N-terminal SPL motif, a C-terminal EAR motif, and a less conserved region in between. The EAR motif is well known as a transcriptional repressor and the presence of this motif in SPEARs suggest that these proteins would also act as repressors. The function of SPL is most well known in the model angiosperm Arabidopsis thaliana. These studies have shown that in spl mutants no functional pollen or female gametophytes are formed. In addition, the MADS-box protein AGAMOUS (AG) directly activates SPL. Therefore, SPL appears to be a key regulator in sporogenesis and may function upstream in its regulatory network. Although, SPL/SPR homologs have been identified across all embryophytes, phylogenetic analyses of these genes have been restricted to model species and no expression nor functional studies have been completed outside Arabidopsis thaliana. In order to better understand the evolution of this gene lineage and its impact on land plant evolution, we have extended the search of homologs across land plants. With Maximum Likelihood analyses, we have found a major clade of SPL, SPEAR1, and SPEAR3 and another clade of SPEAR2 and SPEAR4. Further, SPL is core eudicot-specific, SPEAR1 and SPEAR3 are the result of a duplication event that affected all Brassiceae with orthologs across angiosperms and SPEAR2 and SPEAR4 are the result of a [Office1] duplication event prior to the diversification of Brassicaceae with homologous sequences found across seed plants. To better understand the evolution of this gene lineage across vascular plants, we will perform expression studies by RT-PCR and in situ hybridization in the lycophytes Selaginella apoda L. and Selaginella moellendorffii Hieron as well as the fern Ceratopteris richardii Brongn.

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1 - Columbia University, Environmental Biology, 70 Morningside Dr. #2755, New York, NY, 10027, USA
2 - New York Botanical Garden, 2900 Southern Blvd. Bronx, New York, NY, 10458, United States
3 - The New York Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458, United States

Selaginella apoda
Ceratopteris richardii.

Presentation Type: Recent Topics Poster
Session: P, Recent Topics Posters
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM
Number: PRT027
Abstract ID:1322
Candidate for Awards:None

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