Data from: Molecular mechanisms of postmating prezygotic reproductive isolation uncovered by transcriptome analysis

Little is known about the physiological responses and genetic mutations associated with reproductive isolation between species, especially for postmating prezygotic isolating barriers. Here, we examine changes in gene expression that accompany the expression of ‘unilateral incompatibility’ (UI)—a postmating prezygotic barrier in which fertilization is prevented by gamete rejection in the reproductive tract [in this case of pollen tubes (male gametophytes)] in one direction of a species cross, but is successful in the reciprocal crossing direction. We use whole-transcriptome sequencing of multiple developmental stages of male and female tissues in two Solanum species that exhibit UI to: (i) identify transcript differences between UI-competent and UI noncompetent tissues; (ii) characterize transcriptional changes specifically associated with the phenotypic expression of UI; and (iii) using these comparisons, evaluate the behaviour of a priori candidate loci for UI and identify new candidates for future manipulative work. In addition to describing transcriptome-wide changes in gene expression that accompany this isolating barrier, we identify at least five strong candidates for involvement in postmating prezygotic incompatibility between species. These include three novel candidates and two candidates that are strongly supported by prior developmental, functional, and quantitative trait locus mapping studies. These latter genes are known molecular players in the intraspecific expression of mate choice via genetic self-incompatibility, and our study supports prior evidence that these inter- and intraspecific postmating prezygotic reproductive behaviours share specific genetic and molecular mechanisms.目前学界对物种间生殖隔离（reproductive isolation）相关的生理响应与遗传突变仍缺乏充分认知，尤其是交配后合子前隔离障碍（postmating prezygotic isolating barriers）。本研究聚焦于单侧不亲和（unilateral incompatibility, UI）表达伴随的基因表达变化——单侧不亲和是一种交配后合子前隔离障碍：在物种杂交的单向组合中，生殖道内的配子排斥（此处针对花粉管（pollen tubes），即雄配子体（male gametophytes））会阻断受精过程，但反交组合的受精过程可顺利完成。本研究选取两种表现出单侧不亲和的茄属（Solanum）物种，对其雌雄组织的多个发育阶段开展全转录组测序（whole-transcriptome sequencing），以此达成三项研究目标：其一，识别具备单侧不亲和能力与不具备该能力的组织间的转录本差异；其二，解析与单侧不亲和表型表达特异性相关的转录调控变化；其三，通过上述比较分析，评估单侧不亲和先验候选基因座的功能特性，并筛选出可供后续功能验证实验使用的新候选基因。除阐明该隔离障碍伴随的全转录组水平基因表达变化外，本研究还筛选出至少5个与物种间交配后合子前不亲和相关的强候选基因，其中包含3个全新候选基因，以及2个得到既往发育生物学、功能实验与数量性状位点（quantitative trait locus）定位研究充分支持的候选基因。后两类已知基因是通过遗传自交不亲和（genetic self-incompatibility）实现种内配偶选择的核心分子调控因子，本研究进一步证实：物种间与种内的交配后合子前生殖隔离行为共享特定的遗传与分子机制，这与既往研究结论相符。