Evolutionary Developmental Biology (Evo-Devo)
Wardell, Brian , Malcomber, Simon , Mcsteen, Paula .
Evolution of BARREN STALK2/LAXPANICLE2 (BA2/LAX2) in Angiosperms.
The grass family (Poaceae), the 5thlargest plant family, comprises approximately 10,000 species and includes the cereal crops barley, corn, oats, rice, rye, sorghum, tef and wheat. These grass species provide the bulk of human caloric intake and the grass family dominates ecologically important habitats throughout the world. Much of plant growth is directly or indirectly regulated by the plant hormone auxin. Auxin is primarily synthesized at the tip of the plant and is transported downward in a process known as "Polar Auxin Transport." This network of transport and local biosynthesis gene network creates an increased auxin gradient at the site of axillary meristem (AM) initiation and outgrowth. Although some genes involved in this auxin pathway have been cloned and characterized, there are still gaps in our knowledge of this genetic pathway. Recently, the orthologous maize gene BARRENSTALK2 (BA2) and rice gene LAXPANICLE2 (LAX2) have been cloned and characterized (McSteen unpublished;Tabuchi et al 2011.). Maize ba2 and rice lax2 mutant plants both show significant flaws in AM initiation suggesting a role in auxin regulation. In support of this hypothesis, rice LAX2 interacts with the auxin regulating LAX PANICLE1 (LAX1) protein (Tabuchi 2011). My research will reconstruct the evolutionary history of the BA2/LAX2 lineage and test for conservation of BA2/LAX2 mRNA expression in diverse grasses. My preliminary tree shows three separate BA2/LAX2 grass clades, most likely the result of two separate gene duplication events within monocots. Within the eudicots, two Arabidopsis genes appear to be possible co-orthologs to BA2/LAX2 and BA2/LAX2-like genes, indicating another gene duplication event specific to the eudicots. Conserved gene regions exist between members of each grass clade, supporting the hypothesis that the BA2-like genes reside in syntenic chromosomal regions. In-situ analyses done on Oryza sativa, Sorghum bicolor, and Brachypodium distachyon all showed BA2/LAX2 expression throughout branching meristems, indicating a conserved expression pattern among monocots. These data will provide insight into the mechanisms and conservation of AM formation in diverse grasses.
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1 - California State University, Long Beach, Biological Sciences, 5682 Kern Drive, Huntington Beach, CA, 92649, USA
2 - CSU - Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA
3 - University of Missouri, Biological Sciences, 371 Bond Life Sciences Center, 1201 Rollins Street, Columbia, MO, 65211-7310, USA
Lax Panicle 2
Barren Stalk 2.
Presentation Type: Poster:Posters for Topics
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM