Evolution of Development and Physiology
Kirkbride, Ryan C. , Harada, John J. .
Identification and characterization of LEAFY COTYLEDON 1 in basal land plant taxa.
We have started an investigation into the origins of the LEAFY COTYLEDON 1(LEC1)-type genes, and the possible roles this class of genes may have had in the evolutionary origins of the seed. LEC1 encodes a HAP3 subunit of the CCAAT binding transcription factor (CBF). CBFs are heterotrimeric complexes that act as transcriptional activators in a wide array of eukaryotes. In plants the HAP3 subunits have undergone a multiplication and functional radiation. In Arabidopsis there are ten representatives of the HAP3 subunits, which are divided into two classes based on phylogeny and functional differences: LEC1-type and non-LEC1 type. The LEC1-type, consisting of LEC1 and LEC 1-LIKE (L1L) are expressed in a seed-specific manner and are key regulators of seed development, with roles in both morphogenesis and seed maturation. Using information available from the genome sequencing of basal land plants, we identified multiple HAP3 genes in all basal land plant taxa examined. However, the first appearance of a LEC1-type HAP3 occurred in the seed-free lycophyte Selaginella moellendorffii. The expression of this LEC1-type HAP3 in both sexual and reproductive structures may provide clues about the role that it may have played in basal land plants prior to being co-opted into seed development.
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1 - University of California, Davis, Section of Plant Biology, 1002 Life Sciences, Davis, CA, 95616
2 - University of California, Davis, Section of Plant Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM