Pollen-pistil interactions regulating successful fertilization in the Brassicaceae

L A Chapman,D R Goring

doi:10.1093/jxb/erq021

Abstract

In the Brassicaceae, the acceptance of compatible pollen and the rejection of self-incompatible pollen by the pistil involves complex molecular communication systems between the pollen grain and the female reproductive structures. Preference towards species related-pollen combined with self-recognition systems, function to select the most desirable pollen; and thus, increase the plant's chances for the maximum number of successful fertilizations and vigorous offspring. The Brassicaceae is an ideal group for studying pollen-pistil interactions as this family includes a diverse group of agriculturally relevant crops as well as several excellent model organisms for studying both compatible and self-incompatible pollinations. This review will describe the cellular systems in the pistil that guide the post-pollination events, from pollen capture on the stigmatic papillae to pollen tube guidance to the ovule, with the final release of the sperm cells to effect fertilization. The interplay of other recognition systems, such as the self-incompatibility response and interspecific interactions, on regulating post-pollination events and selecting for compatible pollen-pistil interactions will also be explored.

Highlights

The acceptance of compatible pollen and the subsequent steps leading to successful fertilization is a complex and cooperative process between the pollen and the receptive pistil
At the stigmatic surface of Brassicaceae pistils, there are complex pollen recognition signalling systems at play to determine whether a pollen grain should be accepted
There is evidence to support a ‘family-wide’ pollen recognition system that allows for interspecific and intergeneric crosses; some preference for species-specific pollen may occur by different initial binding affinities of pollen grains (Zinkl et al, 1999; Hiscock and Dickinson, 1993)

Summary

Introduction

The acceptance of compatible pollen and the subsequent steps leading to successful fertilization is a complex and cooperative process between the pollen and the receptive pistil. No pollen tube penetration was observed on self-incompatible B. oleracea pistils when pollinated with different Brassicaceae species/genera pollen, while self-fertile A. thaliana accepted a wide range of pollen grains following the same survey (Hiscock and Dickinson, 1993).

Results

Conclusion