The first SSR-based assessment of genetic variation and structure among Pinus laricio Poiret populations within their native area

Pinus laricio Poiret is the most widespread conifer occurring in Calabria (Sila and Aspromonte Massifs), Sicily (Mount Etna) and Corsica. Particularly, Calabrian laricio pine forests are strongly related to complex geological history, lithological and climatic characteristics and long human exploitation of the Sila territory, of which they are the most emblematic element. As far as we know, the P. laricio populations from their main range areas have never been thoroughly studied at the molecular level. This article reports on the first deep analysis of the genetic variability and structure of individuals from populations located in Calabria, Sicily and Corsica using both chloroplast and nuclear microsatellite markers. Significant variation within populations and low differentiation among populations were found by means of molecular variance estimates for the both types of markers. Bayesian clustering analyses revealed an unexpected grouping of P. laricio populations with individuals from Sila and, particularly, those from the Natural Reserve of Fallistro, have been identified as genetically distinct. Temporal genetic analysis in three large P. laricio populations also showed that there were no differences in genetic diversity levels over time; however, it allowed to recognize populations that deserve to be considered as a high priority for suitable preservation and management.

拉里乔松（Pinus laricio Poiret）是分布于卡拉布里亚（锡拉与阿斯普罗蒙特地块）、西西里岛（埃特纳火山）以及科西嘉岛的最广布针叶树种。尤为值得关注的是，卡拉布里亚拉里乔松林与锡拉地区复杂的地质历史、岩性与气候特征，以及长期的人类开发活动紧密相关，而该松林正是这一区域最具代表性的生态元素。据我们所知，此前从未在分子层面上对其主要分布区内的拉里乔松种群开展过全面深入的研究。本文首次利用叶绿体微卫星标记与核微卫星标记，对分布于卡拉布里亚、西西里岛与科西嘉岛的拉里乔松种群的遗传变异与个体遗传结构开展了深入分析。通过两种标记的分子方差估计，研究团队发现种群内部存在显著的遗传变异，而种群间的遗传分化程度较低。贝叶斯聚类分析结果显示，拉里乔松种群呈现出出人意料的聚类模式：来自锡拉的个体，尤其是法利斯特罗自然保护区的种群个体，被鉴定为遗传上独立的类群。对三个大型拉里乔松种群的时间序列遗传分析同样显示，其遗传多样性水平随时间并未发生显著变化；但该分析结果也帮助我们识别出了需要被列为优先保护与管理对象的种群。