Sex allocation plasticity on a transcriptome scale: Socially sensitive gene expression in a simultaneous hermaphrodite
Sex allocation plasticity on a transcriptome scale: Socially sensitive gene expression in a simultaneous hermaphrodite
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DOI：
10.1111/mec.15077
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发表时间：
2019-05-01
影响因子：
4.9
通讯作者：
Schaerer，Lukas
中科院分区：
文献类型：
--
作者：
Ramm，Steven A.;Lengerer，Birgit;Schaerer，Lukas
表型可塑性可以使生物体在多种环境中产生最佳表型。一个重要的生活史特征，往往是高度可塑性的是性别分配，这在同时雌雄同体描述了相对投资到男性和女性的性功能。理论预测和形态学证据支持，由于精子竞争对男性生殖成功的重要性越来越大，群体规模越大，对男性功能的投资越大。在这里，我们进行了全基因组基因表达测定，以测试这种性别分配可塑性在一个模型同时雌雄同体，自由生活的扁虫Macrostomum lignano。基于来自跨越四个不同组大小处理的16个生物重复的RNA-Seq数据，我们证明了在木质分枝杆菌中超过75，000个研究的转录物中至少有10%根据社会环境差异表达，上升到超过30%的推定性腺特异性转录物（精子发生和卵子发生候选物）和尾部特异性转录物（精液候选物）。这种转录反应密切对应于预期的转变，从女性和男性生殖投资与精子竞争水平的增加。使用整体原位杂交，我们确认许多塑料转录物表现出预期的器官特异性表达，并且对选定的睾丸和卵巢特异性候选物的RNA干扰确定这些确实在配子发生途径中起作用。我们的结论是，大部分的性别特异性转录物在木脂杆菌中根据当时的生态条件差异表达，并且这些在功能上与关键的生殖表型相关。因此，我们的研究开始弥合生物和分子的性别分配可塑性的观点。
Phenotypic plasticity can enable organisms to produce optimal phenotypes in multiple environments. A crucial life history trait that is often highly plastic is sex allocation, which in simultaneous hermaphrodites describes the relative investment into the male versus female sex functions. Theory predicts—and morphological evidence supports—that greater investment into the male function is favoured with increasing group size, due to the increasing importance of sperm competition for male reproductive success. Here, we performed a genome‐wide gene expression assay to test for such sex allocation plasticity in a model simultaneous hermaphrodite, the free‐living flatwormMacrostomum lignano. Based on RNA‐Seq data from 16 biological replicates spanning four different group size treatments, we demonstrate that at least 10% of the >75,000 investigated transcripts inM. lignanoare differentially expressed according to the social environment, rising to >30% of putative gonad‐specific transcripts (spermatogenesis and oogenesis candidates) and tail‐specific transcripts (seminal fluid candidates). This transcriptional response closely corresponds to the expected shift away from female and towards male reproductive investment with increasing sperm competition level. Using whole‐mount in situ hybridization, we then confirm that many plastic transcripts exhibit the expected organ‐specific expression, and RNA interference of selected testis‐ and ovary‐specific candidates establishes that these indeed function in gametogenesis pathways. We conclude that a large proportion of sex‐specific transcripts inM. lignanoare differentially expressed according to the prevailing ecological conditions and that these are functionally relevant to key reproductive phenotypes. Our study thus begins to bridge organismal and molecular perspectives on sex allocation plasticity.