Complex reproductive secretions occur in all extant gymnosperm lineages: a proteomic survey of gymnosperm pollination drops

Date

2019

Authors

Prior, Natalie
Little, Stefan
Boyes, Ian
Griffith, Patrick
Husby, Chad
Pirone‑Davies, Cary
Stevenson, Dennis W.
Tomlinson, P. Barry
von Aderkas, Patrick

Journal Title

Journal ISSN

Volume Title

Publisher

Plant Reproduction

Abstract

Pollination drops are aqueous secretions that receive pollen and transport it to the ovule interior in gymnosperms (Coniferales, Cycadales, Ginkgoales, Gnetales). Proteins are well established as components of pollination drops in conifers (Coniferales) and Ephedra spp. (Gnetales), but it is unknown whether proteins are also present in the pollination drops of cycads (Cycadales), Ginkgo (Ginkgoales), Gnetum (Gnetales), or in the pollination drops produced by sterile ovules occurring on pollen plants in the Gnetales. We used liquid chromatography–tandem mass spectrometry followed by database-derived protein identification to conduct proteomic surveys of pollination drops collected from: Ceratozamia hildae, Zamia furfuracea and Cycas rumphii (Cycadales); Ginkgo biloba (Ginkgoales); Gnetum gnemon and Welwitschia mirabilis, including pollination drops from both microsporangiate and ovulate plants (Gnetales). We identified proteins in all samples: C. hildae (61), Z. furfuracea (40), C. rumphii (9), G. biloba (57), G. gnemon ovulate (17) and sterile ovules from microsporangiate plants (25) and W. mirabilis fertile ovules (1) and sterile ovules from microsporangiate plants (138). Proteins involved in defence and carbohydrate modification occurred in the drops of most groups, indicating conserved functions for proteins in pollination drops. Our study demonstrates that all extant gymnosperm groups produce complex reproductive secretions containing proteins, an ancient trait that likely contributed to the evolutionary success of seed plants.

Description

Keywords

Gymnosperms, Pollination drops, Cycads, Ginkgo, Gnetales, Spermatophytes

Citation

Prior, N., Little, S. A., Boyes, I., Griffith, P., Husby, C., Pirone‑Davies, C., … von Aderkas, P. (2019) Complex reproductive secretions occur in all extant gymnosperm lineages: a proteomic survey of gymnosperm pollination drops. Plant Reproduction, 2019(32). https://doi.org/10.1007/s00497-018-0348-z