Resilience to environmental stressors due to climate warming is influenced by local adaptations, including plastic responses. The recent literature has focused on genomic signatures of climatic adaptation, but little is known about how plastic capacity may be influenced by biogeographic and evolutionary processes. We investigate phenotypic plasticity as a target of climatic selection, hypothesizing that lineages that evolved in warmer climates will exhibit greater plastic adaptive resilience to upper thermal stress. This was experimentally tested by comparing transcriptomic responses within and among temperate, subtropical, and desert ecotypes of Australian rainbowfish subjected to contemporary and projected summer temperatures. Critical thermal maxima were estimated, and ecological niches delineated using bioclimatic modeling. A comparative phylogenetic expression variance and evolution model was used to assess plastic and evolved changes in gene expression. Although 82% of all expressed genes were found in the three ecotypes, they shared expression patterns in only 5 out of 236 genes that responded to the climate change experiment. A total of 532 genes showed signals of adaptive (i.e., genetic-based) plasticity due to ecotype-specific directional selection, and 23 of those responded to projected summer temperatures. Network analyses demonstrated centrality of these genes in thermal response pathways. The greatest adaptive resilience to upper thermal stress was shown by the subtropical ecotype, followed by the desert and temperate ecotypes. Our findings indicate that vulnerability to climate change will be highly influenced by biogeographic factors, emphasizing the value of integrative assessments of climatic adaptive traits for accurate estimation of population and ecosystem responses.

对气候变暖造成的环境压力的抵御能力受到当地适应措施的影响，包括塑料反应。最近的文献主要关注气候适应的基因组特征，但对于生物地理和进化过程如何影响可塑性却知之甚少。我们研究表型可塑性作为气候选择的目标，假设在较温暖的气候中进化的谱系将对上部热应力表现出更大的塑性适应性。这是通过比较澳大利亚彩虹鱼在当前和预计夏季温度下的温带、亚热带和沙漠生态型内部和之间的转录组反应进行实验测试的。估计了临界热最大值，并使用生物气候模型描绘了生态位。使用比较系统发育表达方差和进化模型来评估基因表达的可塑性和进化变化。尽管所有表达基因的 82% 存在于这三种生态型中，但在响应气候变化实验的 236 个基因中，只有 5 个基因具有相同的表达模式。由于生态型特定的定向选择，总共 532 个基因显示出适应性（即基于遗传的）可塑性信号，其中 23 个基因对预计的夏季温度做出了反应。网络分析证明了这些基因在热响应途径中的中心地位。亚热带生态型对高海拔热应力的适应性最强，其次是沙漠和温带生态型。 我们的研究结果表明，气候变化的脆弱性将受到生物地理因素的高度影响，强调了气候适应特征综合评估对于准确估计人口和生态系统反应的价值。