Amaral Danilo T, Bonatelli Isabel A S, Romeiro-Brito Monique, Telhe Milena C, Moraes Evandro M, Zappi Daniela Cristina, Taylor Nigel Paul, Franco Fernando F
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC (UFABC), Santo André, São Paulo, Brazil.
Departamento de Ecologia e Biologia Evolutiva, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil.
Planta. 2024 May 22;260(1):4. doi: 10.1007/s00425-024-04442-x.
Natural selection influenced adaptive divergence between Cereus fernambucensis and Cereus insularis, revealing key genes governing abiotic stress responses and supporting neoteny in C. insularis. Uncovering the molecular mechanisms driving adaptive divergence in traits related to habitat adaptation remains a central challenge. In this study, we focused on the cactus clade, which includes Cereus sericifer F.Ritter, Cereus fernambucensis Lem., and Cereus insularis Hemsley. These allopatric species inhabit distinct relatively drier regions within the Brazilian Atlantic Forest, each facing unique abiotic conditions. We leveraged whole transcriptome data and abiotic variables datasets to explore lineage-specific and environment-specific adaptations in these species. Employing comparative phylogenetic methods, we identified genes under positive selection (PSG) and examined their association with non-synonymous genetic variants and abiotic attributes through a PhyloGWAS approach. Our analysis unveiled signatures of selection in all studied lineages, with C. fernambucensis northern populations and C. insularis showing the most PSGs. These PSGs predominantly govern abiotic stress regulation, encompassing heat tolerance, UV stress response, and soil salinity adaptation. Our exclusive observation of gene expression tied to early developmental stages in C. insularis supports the hypothesis of neoteny in this species. We also identified genes associated with abiotic variables in independent lineages, suggesting their role as environmental filters on genetic diversity. Overall, our findings suggest that natural selection played a pivotal role in the geographic range of these species in response to environmental and biogeographic transitions.
自然选择影响了费氏丝苇（Cereus fernambucensis）和海岛丝苇（Cereus insularis）之间的适应性分化，揭示了控制非生物胁迫反应的关键基因，并支持了海岛丝苇的幼态持续现象。揭示驱动与栖息地适应相关性状适应性分化的分子机制仍然是一个核心挑战。在本研究中，我们聚焦于仙人掌分支，其中包括丝状丝苇（Cereus sericifer F.Ritter）、费氏丝苇（Cereus fernambucensis Lem.）和海岛丝苇（Cereus insularis Hemsley）。这些异域分布的物种栖息在巴西大西洋森林内不同的相对干燥地区，各自面临独特的非生物条件。我们利用全转录组数据和非生物变量数据集来探索这些物种中特定谱系和特定环境的适应性。采用比较系统发育方法，我们鉴定了正选择基因（PSG），并通过系统发育全基因组关联研究（PhyloGWAS）方法研究了它们与非同义遗传变异和非生物属性的关联。我们的分析揭示了所有研究谱系中的选择特征，费氏丝苇北部种群和海岛丝苇显示出最多的正选择基因。这些正选择基因主要控制非生物胁迫调节，包括耐热性、紫外线胁迫反应和土壤盐分适应。我们对海岛丝苇早期发育阶段相关基因表达的独特观察支持了该物种幼态持续的假说。我们还在独立谱系中鉴定了与非生物变量相关的基因，表明它们作为遗传多样性的环境筛选因素的作用。总体而言，我们的研究结果表明，自然选择在这些物种的地理分布范围内对环境和生物地理转变做出了关键反应。
