Nazareno Alison G, Knowles L Lacey, Dick Christopher W, Lohmann Lúcia G
Departamentos de Botânica, Universidade de São Paulo, São Paulo, Brazil.
Department of Genetics, Ecology and Evolution, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Front Plant Sci. 2021 Feb 12;12:626405. doi: 10.3389/fpls.2021.626405. eCollection 2021.
Seed dispersal is crucial to gene flow among plant populations. Although the effects of geographic distance and barriers to gene flow are well studied in many systems, it is unclear how seed dispersal mediates gene flow in conjunction with interacting effects of geographic distance and barriers. To test whether distinct seed dispersal modes (i.e., hydrochory, anemochory, and zoochory) have a consistent effect on the level of genetic connectivity (i.e., gene flow) among populations of riverine plant species, we used unlinked single-nucleotide polymorphisms (SNPs) for eight co-distributed plant species sampled across the Rio Branco, a putative biogeographic barrier in the Amazon basin. We found that animal-dispersed plant species exhibited higher levels of genetic diversity and lack of inbreeding as a result of the stronger genetic connectivity than plant species whose seeds are dispersed by water or wind. Interestingly, our results also indicated that the Rio Branco facilitates gene dispersal for all plant species analyzed, irrespective of their mode of dispersal. Even at a small spatial scale, our findings suggest that ecology rather than geography play a key role in shaping the evolutionary history of plants in the Amazon basin. These results may help improve conservation and management policies in Amazonian riparian forests, where degradation and deforestation rates are high.
种子传播对于植物种群间的基因流动至关重要。尽管在许多系统中，地理距离和基因流动障碍的影响已得到充分研究，但尚不清楚种子传播如何与地理距离和障碍的相互作用共同介导基因流动。为了测试不同的种子传播方式（即水传播、风传播和动物传播）是否对河滨植物物种种群间的遗传连通性（即基因流动）水平有一致的影响，我们对分布在亚马逊盆地一个假定生物地理屏障——布兰科河沿岸的八种共分布植物物种，使用了非连锁单核苷酸多态性（SNP）。我们发现，与种子通过水或风传播的植物物种相比，动物传播的植物物种由于更强的遗传连通性，表现出更高水平的遗传多样性且不存在近亲繁殖现象。有趣的是，我们的结果还表明，布兰科河促进了所有分析植物物种的基因传播，无论其传播方式如何。即使在小空间尺度上，我们的研究结果表明，生态而非地理在塑造亚马逊盆地植物的进化历史中起关键作用。这些结果可能有助于改善亚马逊河岸森林的保护和管理政策，那里的退化和森林砍伐率很高。
