The appearance of plant organs mediated the explosive radiation of land plants, which shaped the biosphere and allowed the establishment of terrestrial animal life. The evolution of organs and immobile gametes required the coordinated acquisition of novel gene functions, the co-option of existing genes and the development of novel regulatory programmes. However, no large-scale analyses of genomic and transcriptomic data have been performed for land plants. To remedy this, we generated gene expression atlases for various organs and gametes of ten plant species comprising bryophytes, vascular plants, gymnosperms and flowering plants. A comparative analysis of the atlases identified hundreds of organ- and gamete-specific orthogroups and revealed that most of the specific transcriptomes are significantly conserved. Interestingly, our results suggest that co-option of existing genes is the main mechanism for evolving new organs. In contrast to female gametes, male gametes showed a high number and conservation of specific genes, which indicates that male reproduction is highly specialized. The expression atlas capturing pollen development revealed numerous transcription factors and kinases essential for pollen biogenesis and function.

植物器官的出现介导了陆生植物的爆炸性辐射，从而塑造了生物圈并允许建立陆生动物生命。器官和固定配子的进化需要新基因功能的协调获取、现有基因的共同选择和新调控程序的开发。然而，尚未对陆生植物进行基因组和转录组数据的大规模分析。为了解决这个问题，我们生成了十种植物的各种器官和配子的基因表达图谱，包括苔藓植物、维管植物、裸子植物和开花植物。对图谱的比较分析确定了数百个器官和配子特异性正交群，并揭示了大多数特定的转录组是显着保守的。有趣的是，我们的结果表明，现有基因的共同选择是进化新器官的主要机制。与雌性配子相比，雄性配子显示出大量且保守的特定基因，这表明雄性繁殖是高度特化的。捕获花粉发育的表达图谱揭示了许多花粉生物发生和功能所必需的转录因子和激酶。