Chanderbali, Andre , Altman, Naomi , Leebens-Mack, Jim , Soltis, Pamela S. , Soltis, Douglas E. .
Microarray profiling of Persea americana flowers: in search of organ-specific gene expression and developmental pathways.
AS part of our goals to investigate the origin, conservation, and diversification of the genetic architecture of the flower, a microarray approach to study floral gene expression has been developed for Persea americana (avocado). This species is one of a set of plant exemplars selected, based on recent phylogenetic studies, to represent the basal angiosperm groups, and to bridge the gap between the plant models Arabidopsis and rice. The microarrays, printed by Agilent Technologies, contain in-situ synthesized 60-mer oligonucleotide probes, representing approximately 6200 unique avocado floral transcripts collected and sequenced by the Floral Genome Project (http://fgp.bio.psu.edu/fgp/index.html). We have examined gene expression in young and medium floral buds, tepals, stamens, carpels, initiating fruit, and leaves using a double loop design. Using a cut-off of two-fold difference, we identified 1354 floral transcripts that were up-regulated in at least one floral tissue compared to leaves. Among the florally up-regulated genes are homologues of AGAMOUS, APETALA3, PISTILLATA and SEPALLATA3, bona-fide floral genes in Arabidopsis. Hierarchical clustering identified several tissue-specific gene clusters. One cluster of ca. 60 genes was primarily expressed in stamens, another group of ca. 60 genes was restricted to tepals, and one of ca. 80 genes was up-regulated in both carpels and fruit. A single cluster of ca. 20 genes was up-regulated in fruit alone, and one of ca. 50 genes was up-regulated only early in floral development. Clustering of tissues suggested that tepals and stamens have similar expression profiles, while carpels and fruits formed a separate cluster. The cluster of ca. 20 genes supporting the clustering of tepals with stamens included the two known Persea homologues of PISTILLATA, a B-class gene in Arabidopsis , and 7 Persea genes without Arabidopsis homologues. These genes are likely participants in a developmental pathway shared between Persea stamens and tepals.
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Floral Genome Project
1 - University of Florida, Department of Botany, Florida Museum of Natural History, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
2 - Pennsylvania State University, Department of Statistics, University Park, Pennsylvania, 16802, USA
3 - Pennsylvania State University, Department of Biology, 403 Life Sciences Building, University Park, Pennsylvania, 16802, USA
4 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM