Male gametophyte development: a molecular perspective

Abstract

Pollen grains represent the highly reduced haploid male gametophyte generation in flowering plants, consisting of just two or three cells when released from the anthers. Their role is to deliver twin sperm cells to the embryo sac to undergo fusion with the egg and central cell. This double fertilization event along with the functional specialization of the male gametophyte, are considered to be key innovations in the evolutionary success of flowering plants. This review encompasses important recent advances in our understanding of the molecular mechanisms controlling male gametophyte development. A brief overview of pollen development is presented, followed by a discussion of genome-wide transcriptomic studies of haploid gene expression. The progress achieved through genetic analysis of landmark events of male gametogenesis is discussed, with a focus on sperm cell production, and an emerging model of the regulatory network governing male germline development is presented. The review concludes with a perspective of the impact these data will have on future research strategies to further develop our understanding of the gametophytic control of pollen development.

Sensitivity of flowering plant gametophytes to temperature fluctuations

“…Thanks to the fast progress in expression profiling and micromanipulation technologies, gene expression is being reported not only for individual structures such as the ovule, the anther, and the male gametophyte, but even at the single cell level such as egg cells and single sperm cells (reviewed in Borg et al, 2009). These approaches are good sound bases for surmounting these difficulties and studying stress response of a specific phase or component of sexual development.…”

An EAR-Dependent Regulatory Module Promotes Male Germ Cell Division and Sperm Fertility in Arabidopsis

“…The male germline is segregated in the gametophyte by asymmetric division of the microspore to form the generative (germ) cell, which rapidly establishes a distinct developmental program. This male germ cell then completes a mitotic division and differentiates to form the two sperm cells required for double fertilization (Borg et al, 2009). In contrast, the female germline is only segregated after three rounds of nuclear division followed by cellularization of the embryo sac (Yadegari and Drews, 2004).…”

Combinatorial interactions between LBD10 and LBD27 are essential for male gametophyte development in Arabidopsis

“…The generative cell undergoes a symmetric cell division called Pollen Mitosis II (PMII) to produce tricellular pollen, which has a vegetative cell and 2 sperm cells. 1,2 The vegetative cell nucleus and the 2 sperm cells migrate into the pollen tube to the embryo sac for double fertilization. 3 Recent studies have revealed several components and the transcription factors which play important roles during male gametophyte development in Arabidopsis.…”