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Abstract Detail

Reproductive biology

Losada, Juan M. [1], Herrero, Maria [2], Hormaza, Jose I. [3], Friedman, William [1].

Stigmatic receptivity marked by the secretion of arabinogalactan proteins in the protogynous Magnolia virginiana.

Stigmatic receptivity is a major player in the progamic phase of offspring production in flowering plants. Although many critical factors affecting flower receptivity in angiosperms remain opaque, recent studies point to the cell wall- related arabinogalactan proteins (AGPs) as clear indicators of the acquisition of stigmatic receptivity in eudicots, monocots, early divergent lineages of angiosperms (Amborella, Nymphaeales, Austrobaileyales), and Chloranthales. Oddly, the magnoliids remain understudied with respect to stigmatic receptivity and AGPs. We evaluated the time during which a stigma is receptive in Magnolia virginiana, a protogynous member of the Magnoliales, with a clearly discernible female receptive phase, and show that secretion of AGPs is tightly integrated with timing of pollen reception and early pollen tube growth in the gynoecial tissues. Protogynous Magnolia flowers display a precise window of stigmatic receptivity concomitant with the secretion of two AGPs labeled for different epitopes. Following pollen germination and pollen tube growth, these two AGPs could no longer be detected in the stigmas, suggesting that these AGPs interact with the growing male gametophytes and could be markers of stigmatic receptivity. Our results show that the period of stigmatic receptivity is finely coordinated with the secretion of two arabinogalactans on stigmas of flowers of M. virginiana. Together with recently described similar patterns in eudicots, monocots, and members of early divergent lineages of flowering plants, our data are congruent with an ancient and widespread role for AGPs on stigmatic receptivity in angiosperms.

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1 - Harvard University, Arnold Arboretum, Organismic and Evolutionary Biology, 1300 Centre Street, Boston, MA, 02131, USA
2 - Aula Dei Experimental Station-CSIC, Pomology, 1005 Avda Montanana, Zaragoza, 50059, Spain
3 - Instituto de Hortofruticultura Tropical y Mediterranea “La Mayora” (IH, Subtropical Fruits, Algarrobo-Costa, Malaga, 29750, Spain

arabinogalactan proteins

Presentation Type: Oral Paper:Papers for Topics
Session: 2
Location: Salon 1/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 8:00 AM
Number: 2001
Abstract ID:947
Candidate for Awards:None

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