Data from: Genomic diversity of a nectar yeast clusters into metabolically, but not geographically, distinct lineages

Both dispersal limitation and environmental sorting can affect genetic variation in populations, but their contribution remains unclear, particularly in microbes. We sought to determine the contribution of geographic distance (as a proxy for dispersal limitation) and phenotypic traits (as a proxy for environmental sorting), including morphology, metabolic ability, and interspecific competitiveness, to the genotypic diversity in a nectar yeast species, Metschnikowia reukaufii. To measure genotypic diversity, we sequenced the genomes of 102 strains of M. reukaufii isolated from the floral nectar of hummingbird-pollinated shrub, Mimulus aurantiacus, along a 200-km coastline in California. Intraspecific genetic variation showed no detectable relationship with geographic distance, but could be grouped into three distinct lineages that correlated with metabolic ability and interspecific competitiveness. Despite ample evidence for strong competitive interactions within and among nectar yeasts, a full spectrum of the genotypic and phenotypic diversity observed across the 200-km coastline was represented even at a scale as small as 200 m. Furthermore, more competitive strains were not necessarily more abundant. These results suggest that dispersal limitation and environmental sorting might not fully explain intraspecific diversity in this microbe and highlight the need to also consider other ecological factors such as trade-offs, source-sink dynamics, and niche modification.

扩散限制（dispersal limitation）与环境筛选（environmental sorting）均可影响种群的遗传变异，但其具体贡献仍不明确，在微生物中尤为如此。本研究旨在明确地理距离（作为扩散限制的替代指标）与表型性状（作为环境筛选的替代指标）对花蜜酵母菌梅奇尼科夫氏酵母（Metschnikowia reukaufii）的基因型多样性的贡献，其中表型性状涵盖形态学特征、代谢能力以及种间竞争能力。为测定基因型多样性，我们对采自加利福尼亚州200公里海岸线沿线、由蜂鸟传粉的灌木橙黄沟酸浆（Mimulus aurantiacus）花蜜中分离得到的102株M. reukaufii菌株进行了基因组测序。种内遗传变异与地理距离未检出显著关联，但可划分为三个独立的演化谱系，且这些谱系与代谢能力及种间竞争能力存在相关性。尽管已有充分证据表明花蜜酵母菌内部及酵母菌类群间存在强烈的竞争互作，但在200公里海岸线范围内观测到的基因型与表型多样性的完整谱系，即便在仅200米的小尺度下也均有体现。此外，竞争能力更强的菌株未必具有更高的丰度。上述结果表明，扩散限制与环境筛选或许无法完全解释该微生物的种内多样性，同时也凸显了需纳入权衡、源汇动态以及生态位修饰等其他生态因素的必要性。