Institute of Plant Sciences, Agricultural Research Organization-Volcani Institute, 7505101, Rishon LeZion, Israel.
BMC Ecol Evol. 2022 Mar 30;22(1):40. doi: 10.1186/s12862-022-01996-w.
The aridity gradient in the eastern Mediterranean offers an opportunity to investigate intra-specific genetic differentiation and local adaptation in plant populations. Here we used genetic (F) and quantitative trait (P) differentiation to assess local adaptation among three natural populations of Eruca sativa (Brassicaceae) distributed along a climatic range representing desert, semi-arid and Mediterranean habitats.
Amplified fragment length polymorphism (AFLP) analysis revealed high genetic diversity in each population, but low genetic differentiation between populations and relatively high gene flow. Further phenotypic evaluation in a common garden experiment (conduced in a Mediterranean habitat) showed clear differences in phenological traits among populations (day of flowering and duration of the reproductive stage), shoot and root biomass, as well as fitness-related traits (total number of fruits and total seed weight). F-P comparison showed that P values of the phenological traits, as well as below- and above-ground biomass and fitness-related traits, were higher than the F values.
Overall, our results support the identification of genotypic and phenotypic differentiation among populations of E. sativa. Furthermore, the F-P comparison supports the hypothesis that these were subjected to past diversifying selection. Thus, the results clearly demonstrate adaptive divergence among populations along an aridity gradient, emphasize the ecological value of early flowering time in arid habitats, and contribute to our understanding of the possible impact of climate change on evolutionary processes in plant populations.
在地中海东部的干旱梯度为研究植物种群的种内遗传分化和适应局部环境提供了机会。本研究采用遗传（F）和数量性状（P）分化来评估三种野生欧洲油菜（芸薹属，十字花科）在代表沙漠、半干旱和地中海生境的气候范围内的适应局部环境的能力。
扩增片段长度多态性（AFLP）分析显示，每个种群都具有较高的遗传多样性，但种群间遗传分化较低，基因流相对较高。在一个共同的花园实验（在一个地中海生境中进行）中的进一步表型评估表明，种群之间存在明显的表型差异（开花日和生殖期持续时间）、地上和地下生物量以及与适应度相关的性状（果实总数和总种子重量）。F-P 比较表明，表型性状的 P 值以及地上和地下生物量以及与适应度相关的性状的 F 值都高于 F 值。
总的来说，我们的结果支持了欧洲油菜种群之间存在基因型和表型分化的观点。此外，F-P 比较支持了这些种群过去经历了多样化选择的假设。因此，研究结果清楚地表明了种群沿干旱梯度的适应分化，强调了在干旱生境中早期开花时间的生态价值，并有助于我们理解气候变化对植物种群进化过程的可能影响。
