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Depletion plays a pivotal role in self-incompatibility, revealing a link between cellular energy status, cytosolic acidification and actin remodelling in pollen tubes.

Published version
Peer-reviewed

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Authors

Carli, José 
Gladala-Kostarz, Agnieszka 

Abstract

Self-incompatibility (SI) involves specific interactions during pollination to reject incompatible ('self') pollen, preventing inbreeding in angiosperms. A key event observed in pollen undergoing the Papaver rhoeas SI response is the formation of punctate F-actin foci. Pollen tube growth is heavily energy-dependent, yet ATP levels in pollen tubes have not been directly measured during SI. Here we used transgenic Arabidopsis lines expressing the Papaver pollen S-determinant to investigate a possible link between ATP levels, cytosolic pH ([pH]cyt ) and alterations to the actin cytoskeleton. We identify for the first time that SI triggers a rapid and significant ATP depletion in pollen tubes. Artificial depletion of ATP triggered cytosolic acidification and formation of actin aggregates. We also identify in vivo, evidence for a threshold [pH]cyt of 5.8 for actin foci formation. Imaging revealed that SI stimulates acidic cytosolic patches adjacent to the plasma membrane. In conclusion, this study provides evidence that ATP depletion plays a pivotal role in SI upstream of programmed cell death and reveals a link between the cellular energy status, cytosolic acidification and alterations to the actin cytoskeleton in regulating Papaver SI in pollen tubes.

Description

Keywords

Papaver rhoeas, ATP, Arabidopsis, actin cytoskeleton, cytosolic acidification, pH, pollen tubes, self-incompatibility, Pollen Tube, Actins, Plant Proteins, Papaver, Arabidopsis, Hydrogen-Ion Concentration, Adenosine Triphosphate

Journal Title

New Phytol

Conference Name

Journal ISSN

0028-646X
1469-8137

Volume Title

Publisher

Wiley
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/P005489/1, BB/T00486X/1)