Wu Wen-Dan, Liu Wen-Hui, Sun Ming, Zhou Ji-Qiong, Liu Wei, Zhang Cheng-Lin, Zhang Xing-Quan, Peng Yan, Huang Lin-Kai, Ma Xiao
1Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
2Key Laboratory of Superior Forage Germplasm in the Qinghai-Tibetan Plateau, Qinghai Academy of Animal Science and Veterinary Medicine, Xining, 81108 China.
Hereditas. 2019 Jan 29;156:8. doi: 10.1186/s41065-019-0082-z. eCollection 2019.
Understanding genetic diversity of wild plant germplasm and the relationships between ecogeographic and genetic characteristics may provide insights for better utilizing and conserving genetic resources. (Nevski) Hand.-Mazz, a cool-season hexaploid perennial, is an important pasture bunchgrass species used for forages and grassland restoration in Qinghai-Tibet Plateau and northwest China. In this study, 27 accessions from diverse origins of western China were evaluated using AFLP markers in an effort to delve into the genetic relationships among them. The effects of eco-environmental factors and geographical isolation on the genetic diversity and population structure were also elucidated.
On account of 554 polymorphic fragments amplified with 14 primer combinations, the mean values of some marker parameters including polymorphic information content, resolving power and marker index were 0.2504, 14.10 and 23.07, respectively, validating the high efficiency and reliability of the markers selected. Genetic dissimilarity index values among accessions ranged from 0.1024 to 0.7137 with a mean of 0.2773. STRUCTURE, UPGMA clustering and PCoA analyses showed that all accessions could be divided into the three main clusters; however, this results do not exactly coincide with geographic groups. We found medium differentiation ( = 0.162) between Qinghai-Tibet Plateau (QTP) and Xinjiang (XJC), and high differentiation ( = 0.188) among three Bayesian subgroups. A significant correlation ( = 0.312) between genetic and geographical distance was observed by Mantel test in the species level, while the weak correlation was detected between genetic and environmental distance for all accessions and most of geographical groups. In addition, a significant ecological influence of average annual precipitation on genetic distance was revealed in XJC group and the Bayesian subgroup A.
This study indicates that AFLP technique are a useful tool to measure genetic diversity in , showing that geographical and environmental factors (especially precipitation) together, play a crucial role in genetic differentiation patterns. These findings underline the importance of local adaptation in shaping patterns of genetic variability and population structure in germplasm collected in Western China.
了解野生植物种质的遗传多样性以及生态地理特征与遗传特征之间的关系，可为更好地利用和保护遗传资源提供见解。（Nevski）Hand.-Mazz是一种冷季六倍体多年生植物，是青藏高原和中国西北部用于饲料和草地恢复的重要牧草丛生禾本科植物。在本研究中，使用AFLP标记对来自中国西部不同来源的27份材料进行了评估，以深入研究它们之间的遗传关系。还阐明了生态环境因素和地理隔离对遗传多样性和种群结构的影响。
利用14对引物组合扩增出554条多态性片段，多态信息含量、分辨力和标记指数等标记参数的平均值分别为0.2504、14.10和23.07，验证了所选标记的高效性和可靠性。材料间的遗传差异指数值在0.1024至0.7137之间，平均值为0.2773。STRUCTURE分析、UPGMA聚类分析和主坐标分析表明，所有材料可分为三个主要类群；然而，这一结果与地理分组并不完全一致。我们发现青藏高原（QTP）和新疆（XJC）之间存在中等分化（Fst = 0.162），三个贝叶斯亚群之间存在高度分化（Fst = 0.188）。在物种水平上，通过Mantel检验观察到遗传距离与地理距离之间存在显著相关性（r = 0.312），而在所有材料和大多数地理组中，遗传距离与环境距离之间的相关性较弱。此外，在XJC组和贝叶斯亚群A中，揭示了年均降水量对遗传距离有显著的生态影响。
本研究表明AFLP技术是测量该植物遗传多样性的有用工具，表明地理和环境因素（尤其是降水量）共同在遗传分化模式中起关键作用。这些发现强调了局部适应性在塑造中国西部收集的该植物种质的遗传变异模式和种群结构中的重要性。
