Research Centre for Ecosystem Resilience, Royal Botanic Gardens and Domain Trust, Sydney, NSW, Australia.
School of Biological Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
Mol Ecol Resour. 2022 Aug;22(6):2171-2182. doi: 10.1111/1755-0998.13605. Epub 2022 Mar 20.
Plant collections are important for the conservation of threatened species, and can provide material for ecological restoration. Typically we want collections to have high genetic diversity so populations founded from it are adaptable to future challenges. Sometimes, we have additional objectives for collections, such as enrichment for desirable traits controlled by adaptive alleles. We used landscape genomic data sets for two plants, Westringia fruticosa and Wilkiea huegeliana, to design collections that are genetically diverse, and that are adapted to warming climates. We characterized temperature adaptation by: (i) using the mean annual temperature of the sites of origin of the plants, and (ii) using the representation of alleles that are associated with warm temperatures. In Westringia fruticosa, there was a negative correlation, or tradeoff, between designing a collection that was both genetically diverse and adapted to warm temperatures. This tradeoff was weaker in Wilkiea huegeliana. We hypothesized this was because neutral genetic variation was strongly correlated with temperature in Westringia fruticosa, and not in Wilkiea huegeliana. Accordingly, when we shuffled the temperature data, breaking up the covariance between Westringia fruticosa genetic variation and temperature, there was a relaxation of the observed tradeoff. In summary, we explore tradeoffs between promoting genetic diversity and selecting for a specific trait in plant collections, and show that the strength of this tradeoff varies between two species. This represents a useful step towards understanding when selection will have a large cost in genetic diversity, and when it will be possible to design a collection that is both adapted and adaptable.
植物收集对于保护受威胁物种非常重要，并且可以为生态恢复提供材料。通常，我们希望收集具有高遗传多样性的植物，以便从其中建立的种群能够适应未来的挑战。有时，我们对收集有额外的目标，例如富集由适应性等位基因控制的理想性状。我们使用两个植物的景观基因组数据集，即 Westringia fruticosa 和 Wilkiea huegeliana，来设计具有遗传多样性和适应气候变暖的收集。我们通过以下两种方法来描述温度适应性：（i）使用植物起源地的年平均温度，以及（ii）使用与温暖温度相关联的等位基因的表达情况。在 Westringia fruticosa 中，设计一个同时具有遗传多样性和适应温暖温度的收集存在负相关或权衡关系。在 Wilkiea huegeliana 中，这种权衡关系较弱。我们假设这是因为在 Westringia fruticosa 中，中性遗传变异与温度之间存在很强的相关性，而在 Wilkiea huegeliana 中则不存在。因此，当我们打乱温度数据，打破 Westringia fruticosa 遗传变异与温度之间的协方差时，观察到的权衡关系得到了放松。总之，我们探讨了在植物收集过程中促进遗传多样性和选择特定性状之间的权衡关系，并表明这种权衡关系在两个物种之间存在差异。这是朝着理解选择在遗传多样性方面将产生多大成本以及何时能够设计出适应性和适应性都很强的收集的方向迈出的有用一步。
