Weinheimer Ellen I, Cory Scott T, Kortessis Nicholas, Anderson T Michael, Pease James B
Department of Biology, Wake Forest University, Winston-Salem, NC, 27109, USA.
Department of Biology, East Carolina University, Greenville, NC, 27858, USA.
Plant J. 2025 Aug;123(3):e70385. doi: 10.1111/tpj.70385.
Drought tolerance involves a complex series of genetic reactions that expand over time as water stress intensifies. We investigated gene expression reactions over 43 days of drought stress in two widespread African savanna trees: the umbrella acacia (Vachellia tortilis) and the splendid thorn acacia (Vachellia robusta). Using 80 transcriptomes from droughted and watered individuals over time, we developed and implemented an analytical approach to identify genes with different reactions between a watered control and droughted treatment population of each species while filtering out genes changing similarly in both populations as part of normal growth and development. Our results show that both species use similar genetic systems to modulate photosynthesis, redox homeostasis, and hormone signaling, but they activate these systems using different sets of genes and on different temporal scales relative to the intensity of drought stress. We also find strong evidence that drought tolerant umbrella acacias demonstrate a surprisingly limited and relatively passive transcriptional response to drought stress, while splendid thorn acacias attempt to actively combat drought stress and maintain a steady state of growth and photosynthesis. Our study provides the first transcriptomic analysis of African acacias and a new model for investigating transcriptomic reactions over long periods of stress.
耐旱性涉及一系列复杂的基因反应，随着水分胁迫加剧，这些反应会随时间扩展。我们研究了两种广泛分布于非洲稀树草原的树木在43天干旱胁迫期间的基因表达反应：伞状金合欢（阿拉伯胶树）和壮丽多刺金合欢。随着时间推移，我们使用来自干旱处理和浇水处理个体的80个转录组，开发并实施了一种分析方法，以识别每个物种的浇水对照群体和干旱处理群体之间具有不同反应的基因，同时滤除作为正常生长和发育一部分而在两个群体中同样发生变化的基因。我们的结果表明，这两个物种都使用相似的遗传系统来调节光合作用、氧化还原稳态和激素信号传导，但它们相对于干旱胁迫强度，使用不同的基因集并在不同的时间尺度上激活这些系统。我们还发现有力证据表明，耐旱的伞状金合欢对干旱胁迫表现出令人惊讶的有限且相对被动的转录反应，而壮丽多刺金合欢则试图积极对抗干旱胁迫并维持生长和光合作用的稳定状态。我们的研究首次对非洲金合欢进行了转录组分析，并提供了一个在长期胁迫下研究转录组反应的新模型。
