Nyati S, Beck A, Honegger R
Institute of Plant Biology, University of Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland.
Plant Biol (Stuttg). 2007 May;9(3):390-9. doi: 10.1055/s-2006-924654. Epub 2006 Nov 13.
According to the literature the microfilamentous thalli of lichen-forming ascomycetes of the genus Psoroglaena are assumed to harbour vivid green "prochlorophyte" cyanobacterial photobionts. As this would be the first report of terrestrial "prochlorophytes" we investigated the fine structure and two molecular markers (SSU rDNA and rbcL) of the photobionts of P. stigonemoides (Orange) Henssen and P. epiphylla Lücking. Both Psoroglaena spp. had unicellular green algal photobionts, representatives of the Trebouxiophyceae. The photobiont of P. stigonemoides is closely related to the non-symbiotic auxenochlorella protothecoides and to a Chlorella endosymbiont of the freshwater polyp Hydra viridis. The putative photobiont of P. epiphylla may be related to Chlorella luteoviridis, C. saccharophila, and a Pseudochlorella isolate. In contrast to other microfilamentous lichens, which derive their shape from filamentous green algae or cyanobacterial colonies overgrown and ensheathed by the fungal partner, Psoroglaena mycobionts position their unicellular photobiont in uni- or multiseriate rows which strongly resemble the situation in filamentous cyanobacterial colonies.
根据文献记载，Psoroglaena属的地衣形成子囊菌的微丝状菌体被认为含有鲜绿色的“原绿藻”蓝藻共生光合生物。由于这将是陆地“原绿藻”的首次报道，我们研究了Stigonemoides Psoroglaena（Orange）Henssen和Epiphylla Psoroglaena Lücking光合生物的精细结构和两个分子标记（小亚基核糖体DNA和核酮糖-1,5-二磷酸羧化酶大亚基基因）。两种Psoroglaena属物种都有单细胞绿藻共生光合生物，属于绿藻纲中的橘色藻科。Stigonemoides Psoroglaena的共生光合生物与非共生的原壳小球藻以及淡水水螅绿藻的一种小球藻内共生体密切相关。Epiphylla Psoroglaena的假定共生光合生物可能与黄绿小球藻、嗜糖小球藻以及一种假小球藻分离株有关。与其他微丝状地衣不同，其他微丝状地衣的形状源自丝状绿藻或被真菌共生体覆盖并包裹的蓝藻菌落，而Psoroglaena属真菌共生体将其单细胞共生光合生物排列成单列或多列，这与丝状蓝藻菌落的情况极为相似。
