Werth Silke, Sork Victoria L
Department of Ecology and Evolutionary Biology, University of California Los Angeles, Box 957239, Los Angeles, California 90095-7239 USA Faculty of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland.
Department of Ecology and Evolutionary Biology, University of California Los Angeles, Box 957239, Los Angeles, California 90095-7239 USA Institute of the Environment and Sustainability, University of California Los Angeles, Box 951496, Los Angeles, California 90095-1496 USA.
Am J Bot. 2014 Jul;101(7):1127-1140. doi: 10.3732/ajb.1400025. Epub 2014 Jul 11.
• Premise of the study: Many lichens exhibit extensive ranges spanning several ecoregions. It has been hypothesized that this wide ecological amplitude is facilitated by fungal association with locally adapted photobiont strains.• Methods: We studied the identity and geographic distribution of photobionts of the widely distributed North American lichen Ramalina menziesii based on rbcL (chloroplast DNA) and nuclear ribosomal ITS DNA sequences. To test for ecological specialization, we associate photobiont genotypes with local climate and phorophyte.• Key results: Of the photobiont lineages of R. menziesii, 94% belong to a clade including Trebouxia decolorans. The remaining are related to T. jamesii. The photobionts showed (1) significant structure according to ecoregion and phorophyte species and (2) genetic associations with phorophyte species and climate.• Conclusions: Geography, climate, and ecological specialization shape genetic differentiation of lichen photobionts. One great advantage of independent dispersal of the fungus is symbiotic association with locally adapted photobiont strains.
• 研究前提：许多地衣呈现出跨越多个生态区域的广泛分布范围。据推测，真菌与本地适应的共生藻菌株的关联促进了这种广泛的生态幅度。
• 方法：我们基于rbcL（叶绿体DNA）和核糖体ITS DNA序列，研究了广泛分布的北美地衣梅氏松萝共生藻的身份和地理分布。为了测试生态特化，我们将共生藻基因型与当地气候和着生植物相关联。
• 关键结果：在梅氏松萝的共生藻谱系中，94%属于包括褪色橘色藻的一个进化枝。其余的与詹姆斯橘色藻相关。共生藻显示出（1）根据生态区域和着生植物种类的显著结构，以及（2）与着生植物种类和气候的遗传关联。
• 结论：地理、气候和生态特化塑造着地衣共生藻的遗传分化。真菌独立传播的一个巨大优势是与本地适应的共生藻菌株的共生关联。
