Borg Michael, Brownfield Lynette, Twell David
Department of Biology, University of Leicester, UK.
J Exp Bot. 2009;60(5):1465-78. doi: 10.1093/jxb/ern355. Epub 2009 Feb 12.
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.
花粉粒代表开花植物中高度简化的单倍体雄配子体世代，从花药中释放时仅由两三个细胞组成。它们的作用是将双精子细胞传递到胚囊，以便与卵细胞和中央细胞融合。这种双受精事件以及雄配子体的功能特化，被认为是开花植物进化成功的关键创新。本综述涵盖了我们对控制雄配子体发育分子机制理解的重要近期进展。首先简要概述了花粉发育，然后讨论了单倍体基因表达的全基因组转录组学研究。讨论了通过对雄配子发生标志性事件的遗传分析所取得的进展，重点是精子细胞的产生，并提出了一个控制雄性生殖系发育的调控网络的新兴模型。综述最后展望了这些数据对未来研究策略的影响，以进一步加深我们对花粉发育配子体控制的理解。
