Méndez-Cea Belén, García-García Isabel, Linares Juan Carlos, Gallego Francisco Javier
Dpto. Genética, Fisiología y Microbiología, Unidad Docente de Genética, Facultad de CC Biológicas, Universidad Complutense de Madrid, Madrid, Spain.
Dpto. Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Sevilla, Spain.
Front Plant Sci. 2023 Aug 11;14:1155441. doi: 10.3389/fpls.2023.1155441. eCollection 2023.
Circum-Mediterranean firs are considered among the most drought-sensitive species to climate change. Understanding the genetic basis of trees' adaptive capacity and intra-specific variability to drought avoidance is mandatory to define conservation measures, thus potentially preventing their extinction. We focus here on and , both relict tree species, endemic from south Spain and north Morocco, respectively. A total of 607 samples were collected from eight nuclei: six from Spanish fir and two from Moroccan fir. A genotyping by sequencing technique called double digestion restriction site-associated DNA sequencing (ddRAD-seq) was performed to obtain a genetic matrix based on single-nucleotide polymorphisms (SNPs). This matrix was utilized to study the genetic structure of populations and to carry out selection signature studies. In order to understand how Spanish fir and Moroccan fir cope with climate change, genotype-environment associations (GEAs) were identified. Further, the vulnerability of these species to climate variations was estimated by the risk of non-adaptedness (RONA). The filtering of the assembly of provided 3,982 SNPs from 504 out of 509 trees sequenced. Principal component analysis (PCA) genetically separated Grazalema from the rest of the Spanish populations. However, F values showed significant differences among the sampling points. We found 51 potentially under selection. Homolog sequences were found for some proteins related to abiotic stress response, such as dehydration-responsive element binding transcription factor, regulation of abscisic acid signaling, and methylation pathway. A total of 15 associations with 11 different were observed in the GEA studies, with the maximum temperature of the warmest month being the variable with the highest number of associated . This temperature sensitivity was also supported by the risk of non-adaptedness, which yielded a higher risk for both and under the high emission scenario (Representative Concentration Pathway (RCP) 8.5). This study sheds light on the response to climate change of these two endemic species.
地中海周边冷杉被认为是对气候变化最敏感的干旱树种之一。了解树木适应能力的遗传基础以及种内抗旱变异性对于制定保护措施至关重要，从而有可能防止它们灭绝。我们在此关注西班牙冷杉和摩洛哥冷杉，它们分别是西班牙南部和摩洛哥北部的残遗树种。总共从八个核心区域采集了607个样本：六个来自西班牙冷杉，两个来自摩洛哥冷杉。采用一种名为双酶切限制性位点关联DNA测序（ddRAD-seq）的测序技术进行基因分型，以获得基于单核苷酸多态性（SNP）的遗传矩阵。该矩阵用于研究种群的遗传结构并开展选择特征研究。为了了解西班牙冷杉和摩洛哥冷杉如何应对气候变化，确定了基因型-环境关联（GEA）。此外，通过非适应性风险（RONA）评估了这些物种对气候变化的脆弱性。对西班牙冷杉基因组组装的筛选从509棵测序树木中的504棵中提供了3982个SNP。主成分分析（PCA）在遗传上把格拉查莱马与西班牙其他种群区分开来。然而，F值在采样点之间显示出显著差异。我们发现51个基因座可能处于选择之中。发现了一些与非生物胁迫反应相关蛋白质的同源序列，如脱水响应元件结合转录因子、脱落酸信号调节和甲基化途径。在GEA研究中总共观察到与11个不同环境变量的15种关联，其中最暖月的最高温度是关联环境变量数量最多的变量。这种温度敏感性也得到了非适应性风险的支持，在高排放情景（代表性浓度路径（RCP）8.5）下，西班牙冷杉和摩洛哥冷杉的非适应性风险都更高。这项研究揭示了这两种特有物种对气候变化的响应。
