Lettuce (Lactuca sativa L.), which belongs to the large Asteraceae (Compositae) family, breeds by sexual reproduction and produces seeds. Actually, lettuce seeds are achenes, which are defined as fruits. However, few studies have described the morphological characteristics of the lettuce achenes, and genes essential for achene development are largely unknown in lettuce. To investigate the gene activity during achene development and determine the possible mechanisms that influence achene development in lettuce, we performed a time-course transcriptome analysis of lettuce achenes. A total of 27,390 expressed genes were detected at the five achene development stages. We investigated the gene expression patterns during achene development and identified the enriched biological processes at the corresponding stages. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses revealed a variety of transcriptomic similarities and differences at different achene development stages. Further, transcription factors and phytohormones were found to play important roles during achene development. Finally, we proposed a working model to illustrate the gene expression modules and possible molecular mechanisms underlying achene development. Our time-course transcriptome data also provide a foundation for future functional studies to reveal the genetic control of achene development in lettuce.

生菜（Lactuca sativaL.)，属于大型菊科（Compositae），通过有性繁殖繁殖并产生种子。实际上，生菜种子是瘦果，被定义为水果。然而，很少有研究描述了莴苣瘦果的形态特征，并且在莴苣中对瘦果发育必不可少的基因在很大程度上是未知的。为了研究瘦果发育过程中的基因活性并确定影响生菜瘦果发育的可能机制，我们对生菜瘦果进行了时程转录组分析。在瘦果发育的五个阶段共检测到 27,390 个表达基因。我们研究了瘦果发育过程中的基因表达模式，并确定了相应阶段的丰富生物过程。京都基因和基因组百科全书和基因本体分析揭示了不同瘦果发育阶段的各种转录组学异同。此外，发现转录因子和植物激素在瘦果发育过程中发挥重要作用。最后，我们提出了一个工作模型来说明瘦果发育的基因表达模块和可能的分子机制。我们的时间进程转录组数据还为未来的功能研究提供了基础，以揭示生菜瘦果发育的遗传控制。我们提出了一个工作模型来说明瘦果发育的基因表达模块和可能的分子机制。我们的时间进程转录组数据还为未来的功能研究提供了基础，以揭示生菜瘦果发育的遗传控制。我们提出了一个工作模型来说明瘦果发育的基因表达模块和可能的分子机制。我们的时间进程转录组数据还为未来的功能研究提供了基础，以揭示生菜瘦果发育的遗传控制。