Abstract

Puccinellia fasciculata is a littoral miohalophyte with a Mediterranean-Atlantic distribution, uncommonly found in inland sites. The main Italian inland population is located in the Salse di Nirano Reserve, an area internationally renowned for the phenomenon of mud volcanoes. In this study, molecular markers are used to characterize this population and its possible relationships with the nearest littoral conspecific population. A survey of ISSR markers revealed low levels of genetic diversity (He = 0.081 in the inland population, 0.105 in the littoral one) and a weak genetic differentiation (Gst = 0.24 within the inland population, 0.28 among this and the littoral one). A sequence analysis of three non-coding regions of chloroplast DNA found no genetic differentiation both within the inland population and between the two populations, and revealed a common origin for the two dating back to the middle Holocene. The apparent incongruence between the results from the two approaches may be explained by differences between ISSR and non-coding cpDNA markers in capturing signatures related to gene flow; their integrated information implies a mixed reproductive strategy and a common evolutionary history for the two examined populations. Effective conservation strategies are recommended for the inland population of P. fasciculata and its habitat.

摘要

Puccinellia fasciculata是一种沿地中海-大西洋分布的盐生植物，在内陆地区很少见。意大利内陆人口主要集中在萨尔塞迪尼拉诺保护区，该地区因泥火山现象而享誉国际。在这项研究中，分子标记用于表征该种群及其与最近的沿海同种种群的可能关系。对 ISSR 标记的调查显示遗传多样性水平低（内陆人群He  = 0.081，沿海人群为 0.105）和弱遗传分化（Gst = 0.24 在内陆人口中，0.28 在内陆人口中）。对叶绿体 DNA 的三个非编码区的序列分析发现，在内陆种群内和两个种群之间没有遗传分化，并揭示了两者的共同起源可追溯到全新世中期。两种方法的结果之间明显的不一致可以通过 ISSR 和非编码 cpDNA 标记在捕获与基因流动相关的特征方面的差异来解释。他们的综合信息意味着两个被检查种群的混合繁殖策略和共同的进化历史。建议对P. fasciculata的内陆种群及其栖息地采取有效的保护策略。