Evolution of lichen-forming fungi, algae, and secondary metabolites

覆盖北部生态系统的大片地衣形成了藻类和真菌（共生体）之间相互作用（共生）的马赛克。这些地衣的广泛成功可能归因于藻类共生体和真菌次生代谢物（聚酮）。光合作用产生的藻类碳水化合物被转移给真菌伙伴，并用于聚酮合成。聚酮类化合物具有生态效益，如遮光和抗菌活性，有助于地衣在其栖息地生存，但它们也可能在生物技术方面有应用。本研究计划的长期目标是了解地衣共生体及其聚酮在地衣占主导地位的栖息地的功能生态学和进化。***我将研究分布在大陆和沿海栖息地的4种Cladonia的藻类共生和真菌聚酮生产的生态模式。这些物种的不同化学型将为2个MSc项目测试藻类共生体和气候影响聚酮生产的假设。由于藻类对地衣共生至关重要，因此在共生相互作用的早期阶段就应该产生有助于保护藻类免受不利条件影响的聚酮。因此，我的第二个博士和2个理学士项目的目标是比较两种培养处理中转录活性PKS基因；真菌单独生长，真菌和藻类相互作用。这项研究将揭示活跃的PKS基因在存在和不存在藻类。由于假设生长条件会影响聚酮的产生，博士、3个理学士和PDF项目的第三个目标是比较在不同条件下生长的C. rangiferina的转录组，以确定差异转录的PKS基因，为进一步的生物技术研究提供基因功能的见解。***我的研究项目提供了更好的理解在地衣为主的栖息地中地衣共生的进化和适应策略，但这项拟议的研究将解决藻类在聚酮合成中的作用，在相互作用的早期阶段建立PKS基因转录，并检查生态效益和分离PKS基因的生物技术。10个HQP被整合在拟议的研究中，用于解决当前问题的前沿技术培训主题-发现新的生物活性分子和环境变化对维持北极生物多样性的影响。*****

Large expanses of lichens that cover northern ecosystems form a mosaic of interactions (symbioses) between algae and fungi (symbionts). The widespread success of these lichens may be attributed to the algal symbiont and fungal secondary metabolites (polyketides). Algal carbohydrates from photosynthesis are transferred to the fungal partner and used in polyketide synthesis. Polyketides have ecological benefits such as light screening and antimicrobial activity that help the lichen survive in its habitat, but they may also have applications in biotechnology. The long-term goal of this research program is to understand the functional ecology and evolution of lichen symbionts and their polyketides in lichen dominated habitats.***I will investigate ecological patterns in the algal symbiont and fungal polyketide production in 4 Cladonia species distributed among continental and coastal habitats. The varied chemotypes of these species will test hypotheses for 2 MSc projects that the algal symbiont and climate influence polyketide production. Since the alga is essential for the lichen symbiosis, polyketides that help protect the alga from adverse conditions should be produced in early stages of the symbiont interaction. Therefore, my second objective for a PhD and 2 BSc projects is to compare transcriptionally active PKS genes in 2 culture treatments; the fungus growing alone and the fungus and alga interacting together. This study will reveal active PKS genes in the presence and absence of the alga. Since growing conditions have been hypothesized to affect polyketide production, the third objective for a PhD, 3 BSc, and PDF projects is to compare transcriptomes from C. rangiferina grown under different conditions to identify the differentially transcribed PKS genes providing insights into gene function leading to further biotechnology studies. ***My research program has provided a better understanding of the evolutionary and adaptive strategies of lichen symbioses in lichen-dominated habitats but this proposed research will address the role of the alga in polyketide synthesis, establish PKS gene transcription at early stages in the interaction, and examine ecological benefits and isolation of PKS genes for biotechnology. Ten HQP are integrated within the proposed research for training in leading edge technology on topics addressing current day issues – discovery of new bioactive molecules and impact of environmental change on the maintenance of arctic biodiversity.*****