Abstract Detail

Development and Structure

Mendelson, Ellie [1], Zumajo, Cecilia [2], Ambrose, Barbara [3].

Filling in the gaps: The genetic network of fruit development in Austrobaileya scandens and Illicium floridanum (Austrobaileyales).

The genetic mechanisms regulating fruit development have been well-studied in Arabidopsis thaliana. One part of this complex genetic network includes seven different transcription factors, each belonging to a different major gene family. In A. thaliana fruits, proper valve development is controlled by FRUITFULL (FUL) that represses SHATTERPROOF1/2 (SHP1/SHP2). SHP1/2 are also repressed indirectly by two genes responsible for replum formation: REPLUMLESS (RPL) and BREVIPEDICELLUS (BP). On the other hand, INDEHISCENT (IND) and ALCATRAZ (ALC) function downstream of SHP1/2 at the dehiscence zone (DZ), where they control lignified and un-lignified layers, respectively. SPATULA (SPT) seems to have a redundant role with ALC specifying the DZ. APETALA2 (AP2) represses SHP and BP, indirectly regulating this part of the fruit genetic network. Phylogenetic analyses of each of these 7 gene families have shown that major duplications in these gene lineages coincide with paleo-polyploidization events independently affecting the evolution of each gene lineage. Therefore, the genetic complement found in Arabidopsis is not readily extrapolated to other angiosperms.  To better understand the evolution of the fruit genetic network, we investigated the expression patterns of these transcription factors in the early diverging angiosperms Austrobaileya scandens and Illicium floridanum (Austrobaileyales) each with different fruit morphologies; A. scandens has fleshy fruits and I. floridanum has an explosive dry fruit known as follicle. We dissected the different floral organs from pre-anthetic and anthetic flowers, young fruits and leaves from the two species and subsequently performed gene expression analysis by quantitative RT-PCR for genes putatively involved in the fruit developmental network. Each gene showed broad patterns of expression, indicating that these genes may have less specific roles outside of Arabidopsis. Our results provide a fuller framework for additional experiments to better understand the evolution of these genes and their roles in fruit development across angiosperms.

1 - Arnold Arboretum of Harvard University, 1300 Centre Street, Boston, MA, 02131, USA
2 - Università degli Studi di Milano, Dipartimento di BioScienze-piano 3 torre A, Via Celoria 26 - 20133 Milano, Italia
3 - The New York Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458, United States

Early diverging angiosperms
Fruit development
Genetic network

Presentation Type: Poster
Number: PDS009
Abstract ID:457
Candidate for Awards:Developmental and Structural Section best poster

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