Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Zumajo, Cecilia [1], Pabon Mora, Natalia [2], Ambrose, Barbara [3].

Expression and functional studies of basal eudicot REPLUMLESS homologs during flower and fruit development. .

REPLUMLESS (RPL) belongs to the TALE class of Homeodomain proteins and is known for its role in Arabidopsis for proper replum development. Arabidopsis thaliana has a bicarpellate silique, when the fruit matures, the two valves fall apart through the dehiscence zone leaving the seeds attached to the remaining medial tissue, called the replum. Although siliques have been described only in Brassicaceae, operculate valvate dehiscence with persistent medial tissue, similar to a replum, can occur in other unrelated plant groups like the plume poppies (Bocconia frutescens). RPL orthologs have been identified across all angiosperms, and been shown to have conserved roles in Brasssicaceae, nevertheless, expression and functional analyses are scarce. An RPL homolog from rice, qSH1, has been studied and plays a role in fruit shedding making it difficult to predict functional evolution of this gene lineage across angiosperms. In order to fill in the phylogenetic gap between the Brassicaceae and monocots, we have characterized the expression patterns of RPL homologs found in the basal eudicots Papaver somniferum, PsomRPL and B. frutescens, BofruRPL1/2/3. We found PsomRPL expressed in the shoot apical meristem and developing leaves. Although PsomRPL is not expressed in early flower development, it is expressed later in the joints of the floral organs and the receptacle as well as in the vasculature of the flower receptacle and fruits. This late floral expression of PsomRPL is similar to BofrRPL1 which is mostly expressed during late flower development in stamens, carpels, ovary, and later during fruit development it gets restricted to the dehiscence zone. Distinctively, BofruRPL2 and BofruRPL3 are turned on earlier during sepal initiation, and later in the carpel primordia as well as during fruit development, exclusively in the dehiscence zone. BofruRPL3 is also expressed in the shoot apical meristem. Functional studies of RPL in Papaver somniferum resulted in flowers where none of the organs abscise at floral maturity. This phenotype is concurrent with PsomRPL expression found in the joints of the different floral organs and the receptacle. We conclude that that RPL orthologs in Papaveraceae have broad expression patterns across plant development similar to those found in Arabidopsis RPL. And unlike Arabidopsis, our results do not suggest conserved roles in the maintenance of medial persistent tissues during the development of valvate poppy fruits. Our data gathered from Papaveraceae will be discussed with preliminary data from across angiosperms.

1 - New York Botanical Garden, 2900 Southern Blvd. Bronx, New York, NY, 10458, United States
2 - Universidad De Antioquia, Ciudad Universitaria, Aa1226, Medellin, AA1226, Colombia
3 - Calle 18b Sur No 36-88, Medellin, ANT, AA1226, Colombia

Keywords:
REPLUMLESS
Papaveraceae
Bocconia frutescens 
Papaver somniferum.

Presentation Type: Oral Paper
Session: 20, Evolutionary Developmental Biology (Evo-Devo) I
Location: 113/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 8:15 AM
Number: 20002
Abstract ID:136
Candidate for Awards:Katherine Esau Award