Evolutionary Developmental Biology (Evo-Devo)
Lopez, Christopher , Malcomber, Simon .
Phylogenomic analyses of the VANISHING TASSEL2 in grasses.
The VANISHING TASSEL2 gene in maize is essential for vegetative development and axillary meristem formation during inflorescence development. Phylogenetic analysis indicate that VT2 is co-orthologus to the Arabidopsis TRYPTOPHAN AMINOTRANSFERASE (AtTAA1), which catalyzes the conversion of Trp to indole-3-pyruvic acid in one of four hypothesized Trp-dependent biosynthesis pathways for production of the plant growth hormone indole acetic acid (IAA). Bayesian phylogenetic analysis reveals a well-supported VT2/VT2L clade comprised of grasses from both the BEP and PACCMAD lineages suggesting an origin of the clade at least near the base of the grass family and potentially deeper within monocots. VT2 is estimated have been produced from a gene duplication within andropogonoid grasses, but phylogenetic and genomic analyses indicate VT2 orthologs are restricted to maize. Genome analyses reveal a high degree of synteny among VT2L genes in Brachypodium, rice and sorghum, but only limited evidence of synteny among these taxa and the maize VT2 and VT2L genes. RT-PCR expression analyses indicate VT2L and TAR3/4L genes are expressed broadly, to varying degrees, in leaves, stems and inflorescence material, however the Sorghum SbVT2L2 and Brachypodium BdVT2L2 were not detected within stem tissue and were only weakly expressed in leaf and inflorescence material. Similar to mRNA in situ expression analyses of maize ZmVT2, Sorghum SbVT2L was localized to the epidermal layer in developing inflorescence tissue and was most pronounced in areas with initiating lateral meristems. Together these data suggest a general role of TAA-like genes in regulating plant growth and development in plants, but also point to a complex evolutionary history of VT2 and VT2L genes in grasses.
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1 - California State University, Long Beach, Biological Sciences, 1250 Bellflower Blvd., Long Beach, Ca, 90840, USA
2 - CSU - Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA
Presentation Type: Poster:Posters for Topics
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM