Timing control of sexual reproduction in haploid-dominant plants: MFT and DOG1

减数分裂有性生殖是多细胞真核生物的共同特征。在许多生物谱系中，单倍体或二倍体阶段都是多细胞的。然而，陆地植物进化出了一个特殊的单倍体生活史，其中单倍体配子体和二倍体孢子体都是多细胞的。这种世代交替显然是通过合子阶段有丝分裂的插入而演变的。植物的有性繁殖包括配子形成器官的产生(配子导管发生)、单倍体配子的形成、受精形成二倍体合子、胚胎发生、孢子或种子形成，最后是停滞/休眠的打破(萌发)。这些步骤的时机，特别是有性繁殖的开始(配子血管生成)和结束(萌发)，是通过对环境提示做出反应的调节网络来控制的。开花植物进行一种特别复杂和进化的有性繁殖衍生形式，由于配子体世代的减少，很难进行研究。在这里，我们建议研究单倍体优势植物，即苔藓植物，在这些植物中，两个世代都很容易驯化。通过将三管齐下的候选基因方法与随后的反向遗传学研究相结合，我们将致力于推断陆地植物有性繁殖的时间控制是如何进化的。

Meiotic sexual reproduction is a common feature of multicellular eukaryotes. In many organismal lineages either the haploid or diploid phase is multicellular. Land plants, however, evolved a peculiar haplodiplontic life cycle in which both the haploid gametophyte and the diploid sporophyte are multicellular. This alternation of generations apparently evolved by intercalation of mitoses at the stage of the zygote. Sexual reproduction in plants involves the generation of gamete-forming organs (gametangiogenesis), the formation of haploid gametes, fertilization to form the diploid zygote, embryogenesis, spore or seed formation, and finally the breaking of arrest/dormancy (germination). Timing of these steps, in particular the start (gametangiogenesis) and end (germination) of sexual reproduction, are controlled via regulatory networks that respond to environmental cues. Flowering plants perform a particularly complex and evolutionary derived form of sexual reproduction, and are difficult to study due to the reduction of the gametophytic generation. Here, we thus propose to study haploid-dominant plants, namely bryophytes, in which both generations are easily tractable. By applying a three-pronged candidate gene approach with subsequent reverse genetics studies we will aim to infer how time control of land plant sexual reproduction evolved.