Planta

, Volume 224, Issue 2, pp 233–245

Gametophytic self-incompatibility: understanding the cellular mechanisms involved in “self” pollen tube inhibition

Review

DOI: 10.1007/s00425-006-0284-2

Cite this article as:
McClure, B.A. & Franklin-Tong, V. Planta (2006) 224: 233. doi:10.1007/s00425-006-0284-2

Abstract

Self-incompatibility (SI) prevents the production of “self” seed and inbreeding by providing a recognition and rejection system for “self,” or genetically identical, pollen. Studies of gametophytic SI (GSI) species at a molecular level have identified two completely different S-genes and SI mechanisms. One GSI mechanism, which is found in the Solanaceae, Rosaceae and Scrophulariaceae, has S-RNase as the pistil S-component and an F-box protein as the pollen S-component. However, non-S-locus factors are also required. In an incompatible situation, the S-RNases degrade pollen RNA, thereby preventing pollen tube growth. Here, in the light of recent evidence, we examine alternative models for how compatible pollen escapes this cytotoxic activity. The other GSI mechanism, so far found only in the Papaveraceae, has a small secreted peptide, the S-protein, as its pistil S-component. The pollen S-component remains elusive, but it is thought to be a transmembrane receptor, as interaction of the S-protein with incompatible pollen triggers a signaling network, resulting in rapid actin depolymerization and pollen tube inhibition and programmed cell death (PCD). Here, we present an overview of what is currently known about the mechanisms involved in regulating pollen tube inhibition in these two GSI systems.

Keywords

Actin depolymerizationCalcium signalingF-boxProgrammed cell death (PCD)S-RNaseSelf-incompatibility

Abbreviations

SI

Self-incompatibility

GSI

Gametophytic self-incompatibility

[Ca2+]i

Intracellular cytosolic free calcium concentration

ECM

Extracellular matrix

ABP

Actin binding protein

MAPK

Mitogen activated protein kinase

PCD

Programmed cell death

PARP

Poly (ADP-ribose) polymerase

cyt c

Cytochrome c

S-RNase

S-locus ribonuclease

SLF/SFB

S-locus F-box

 120K

120 kDa glycoprotein

SC

Self-compatible

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Department of Biochemistry105 Christopher S. Bond Life Sciences CenterColumbiaUSA
  2. 2.School of BiosciencesUniversity of BirminghamEdgbaston, BirminghamUK