Zhang Jing-Xue, Wang Miaoli, Fan Jibiao, Guo Zhi-Peng, Guan Yongzhuo, Qu Gen, Zhang Chuan-Jie, Guo Yu-Xia, Yan Xuebing
College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China.
College of Animal and Veterinary Science, Henan Agricultural University, Zhengzhou, Henan, China.
PeerJ. 2021 Aug 17;9:e11953. doi: 10.7717/peerj.11953. eCollection 2021.
Environmental variation related to ecological habitat is the main driver of plant adaptive divergence. Longitude plays an important role in the formation of plant population structure, indicating that environmental differentiation can significantly shape population structure.
Genetic diversity and population genetic structure were estimated using 105 expressed sequence tag-derived simple sequence repeat (EST-SSR) loci. A total of 249 (L.) Pers. (common bermudagrass) individuals were sampled from 13 geographic sites along the longitude (105°57'34″-119°27'06″E).
There was no obvious linear trend of intra-population genetic diversity along longitude and the intra-population genetic diversity was not related to climate in this study. Low gene flow (Nm = 0.7701) meant a rich genetic differentiation among populations of along longitude gradients. Significantly positive Mantel correlation ( = 0.438, = 0.001) was found between genetic distance and geographical interval while no significant partial Mantel correlation after controlling the effect of mean annual precipitation, which indicated geographic distance correlated with mean annual precipitation affect genetic distance. The genetic diversity of with higher ploidy level was higher than that with lower ploidy level and groups of individuals with higher ploidy level were separated further away by genetic distance from the lower ploidy levels. Understanding the different genetic bases of local adaptation comparatively between latitude and longitude is one of the core findings in the adaptive evolution of plants.
与生态栖息地相关的环境变异是植物适应性分化的主要驱动力。经度在植物种群结构形成中起重要作用，表明环境分化可显著塑造种群结构。
利用105个表达序列标签衍生的简单序列重复（EST-SSR）位点估计遗传多样性和种群遗传结构。从沿经度（105°57'34″-119°27'06″E）的13个地理位点采集了总共249株狗牙根（Cynodon dactylon (L.) Pers.）个体。
本研究中，种群内遗传多样性沿经度没有明显的线性趋势，且种群内遗传多样性与气候无关。低基因流（Nm = 0.7701）意味着沿经度梯度的种群间存在丰富的遗传分化。在控制年平均降水量的影响后，遗传距离与地理间隔之间存在显著的正Mantel相关性（r = 0.438，P = 0.001），而部分Mantel相关性不显著，这表明与年平均降水量相关的地理距离影响遗传距离。倍性水平较高的狗牙根的遗传多样性高于倍性水平较低的，且倍性水平较高的个体组在遗传距离上与倍性水平较低的个体组分隔得更远。比较理解纬度和经度之间局部适应的不同遗传基础是植物适应性进化的核心发现之一。
