Conservation and divergence of gene expression plasticity following c. 140 million years of evolution in lodgepole pine (Pinus contorta) and interior spruce (Picea glauca × Picea engelmannii)

Species respond to environmental stress through a combination of genetic adaptation and phenotypic plasticity, both of which may be important for survival in the face of climatic change. By characterizing the molecular basis of plastic responses and comparing patterns among species, it is possible to identify how such traits evolve. Here, we use de novo transcriptome assembly and RNA-seq to explore how patterns of gene expression differ in response to temperature, moisture, and light regime treatments in lodgepole pine (Pinus contorta) and interior spruce (a natural hybrid population of Picea glauca and Picea engelmannii). We found wide evidence for an effect of treatment on expression within each species, with 6,413 and 11,658 differentially expressed genes identified in spruce and pine, respectively. Comparing patterns of expression among these species, we found that 74% of all orthologs with differential expression had a pattern that was conserved in both species, despite 140 million...物种通过遗传适应与表型可塑性的协同作用响应环境胁迫，二者均为应对气候变化时物种存续的关键机制。通过解析塑性响应的分子基础并比较不同物种间的表达模式，可揭示此类性状的演化路径。本研究采用从头转录组组装（de novo transcriptome assembly）与RNA测序（RNA-seq）技术，探究扭叶松（Pinus contorta）与内陆云杉（白云杉（Picea glauca）与恩格尔曼云杉（Picea engelmannii）的自然杂交种群）在温度、湿度及光照处理下的基因表达差异模式。研究发现，处理对两个物种的基因表达均存在广泛影响，分别在云杉与扭叶松中鉴定出6413个与11658个差异表达基因（differentially expressed genes）。通过比较上述物种间的表达模式，本研究发现尽管二者已分化达1.4亿年之久，所有具有差异表达的直系同源基因中仍有74%的表达模式在两个物种中保持保守。