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功于藻类共生体和真菌次生代谢物(聚酮)。来自光合作用的藻类碳水化合物被转移到真菌伙伴，并用于聚酮的合成。聚酮类化合物具有生态效益，如遮光和抗菌活性，帮助地衣在其栖息地生存，但它们也可能在生物技术中应用。这项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优势的生境中的功能生态和进化。 我将研究分布在大陆和沿海生境的4种枝状藻类的藻类共生体和真菌聚酮的生态格局。这些物种的不同化学类型将检验两个理学硕士项目的假设，即藻类共生体和气候影响聚酮的生产。由于藻类对地衣共生是必不可少的，所以在共生体相互作用的早期阶段，应该产生有助于保护藻类免受不利条件影响的聚酮类化合物。因此，我的博士和2个理科学士项目的第二个目标是比较两种培养处理中转录活性的PKS基因；真菌单独生长以及真菌和藻类相互作用。这项研究将揭示在藻类存在和不存在的情况下活跃的PKS基因。由于生长条件被假设会影响多酮的生产，PHD、3 BSC和PDF项目的第三个目标是比较在不同条件下生长的兰考的转录本，以确定差异转录的PKS基因，为进一步的生物技术研究提供对基因功能的洞察。 我的研究计划为地衣主导的生境中地衣共生的进化和适应策略提供了更好的理解，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PKS基因的分离用于生物技术。十个HQP被纳入拟议的前沿技术培训研究，主题涉及当今问题、新的生物活性分子的发现以及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.