Pease James B, Guerrero Rafael F, Sherman Natasha A, Hahn Matthew W, Moyle Leonie C
Department of Biology, Indiana University, 1001 East Third Street, Bloomington, IN, 47405, USA.
School of Informatics and Computing, Indiana University, 1001 East Third Street, Bloomington, IN, 47405, USA.
Mol Ecol. 2016 Jun;25(11):2592-608. doi: 10.1111/mec.13679. Epub 2016 May 30.
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.
关于物种间生殖隔离所涉及的生理反应和基因突变，我们了解甚少，尤其是对于交配后合子前隔离屏障。在此，我们研究了伴随着“单向不亲和性”（UI）表达的基因表达变化，UI是一种交配后合子前屏障，在物种杂交的一个方向上，受精在生殖道中（在这种情况下是花粉管（雄配子体））因配子排斥而被阻止，但在反交方向上受精成功。我们对表现出UI的两个茄属物种的雄性和雌性组织的多个发育阶段进行全转录组测序，以：（i）确定有UI能力和无UI能力的组织之间的转录差异；（ii）表征与UI表型表达特异性相关的转录变化；以及（iii）通过这些比较，评估UI先验候选基因座的行为，并识别未来操作研究的新候选基因。除了描述伴随这种隔离屏障的全转录组范围的基因表达变化外，我们还确定了至少五个参与物种间交配后合子前不亲和性的有力候选基因。其中包括三个新的候选基因和两个在先前的发育、功能和数量性状基因座定位研究中得到有力支持的候选基因。后两个基因是通过遗传自交不亲和在种内配偶选择表达中的已知分子参与者，我们的研究支持了先前的证据，即这些种间和种内交配后合子前生殖行为共享特定的遗传和分子机制。
