Systems and life history analysis of fungal adaptations to extreme environments

真菌适应极端环境的系统和生活史分析

• 批准号: RGPIN-2018-05349
• 负责人: Harris, Steven
• 金额: $ 2.62万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=713307
• 关键词: Systems; life; history; analysis; fungal

Extremotolerant fungi occupy diverse niches that are exposed to severe stress and lack obvious nutrient sources. Prevalent examples of such niches in Canada include rock surfaces and semi-arid soils. Fungi employ a diverse array of strategies to successfully adapt to these stressful habitats, including slow growth, simplified morphologies, and the accumulation of protective pigments. Understanding the regulatory networks that coordinate these responses will provide valuable insight into the evolution of the extremophile lifestyle in the fungal kingdom. Moreover, comparison to other microbial and plant extremophiles will enable a broader perspective on how sessile organisms successfully adapt to and colonize harsh environments. Given the importance of fungi as a source of strains and enzymes used for industrial applications, better characterization of the mechanisms that promote adaptation to stressful habitats will also be likely to have applied significance. The objective of my research program is to investigate mechanisms that underlie the ability of the extremotolerant fungi such as Exophiala dermatitidis and Knufia petricola to adapt to stress and to secure adequate nutrition. Whereas the role of protective pigments such as carotenoids and melanin in mediating stress resistance has been established in these fungi, the regulatory pathways that direct the production of these pigments are poorly understood. Preliminary data generated by my lab shows that the conserved GTPase Cdc42 regulates light-induced carotenoid accumulation and have identified a conserved circadian regulator that likely coordinates the diurnal production of pigments and other stress responsive functions. I propose the use of genomic and genetic approaches to further investigate the role of light and circadian responses in the ability to tolerate stress (Aim #1). My lab has also succeeded in engineering artificial mutualisms with the alga Chlorella sorokiniana that enhance viability of E. dermatitidis. I propose to generate additional mutualisms and to use them to define key morphological and metabolic features that underlie the capacity of fungi to acquire nutrient from photoautotrophs (Aim #2). Lastly, my lab has begun to assemble a large collection of extremotolerant fungi, algae, and cyanobacteria from rock surfaces and biological soil crusts in Canada. I propose to expand and leverage this collection to determine the extent to which "transient lichenization" of photoautotrophs represents a general strategy used by extremotolerant fungi to secure nutrition in harsh ecosystems. My research program will provide a robust, cutting-edge training experience for up to 12 HQP (2 PhD, 2 MSc, 8 BSc). Our collective efforts over the next five years will generate unprecedented new insight into the adaptations that have expanded the terrestrial environments available for colonization by eukaryotic life.

极端耐受真菌占据着各种各样的生态位，暴露在严重的压力下，缺乏明显的营养来源。在加拿大，这种生态位的普遍例子包括岩石表面和半干旱土壤。真菌采用了一系列不同的策略来成功地适应这些应激的生境，包括缓慢的生长、简化的形态和保护性色素的积累。了解协调这些反应的调控网络将为真菌王国极端微生物生活方式的演变提供宝贵的见解。此外，与其他微生物和植物极端微生物进行比较，将使我们能够更广泛地了解固着生物如何成功地适应和定居恶劣环境。鉴于真菌作为用于工业应用的菌株和酶的来源的重要性，更好地描述促进适应压力大的生境的机制也可能具有应用意义。我的研究计划的目的是研究极端耐受性真菌，如皮炎外隐孢子菌和Knufia Petricola适应压力和确保足够营养的能力的机制。虽然在这些真菌中，类胡萝卜素和黑色素等保护性色素在调节抗逆性方面的作用已经确定，但指导这些色素产生的调控途径却知之甚少。我的实验室产生的初步数据显示，保守的GTPase CDC42调控光诱导的类胡萝卜素积累，并发现了一个保守的昼夜节律调节因子，可能协调色素的日常生产和其他应激反应功能。我建议使用基因组和遗传方法来进一步研究光和昼夜节律反应在耐受压力能力中的作用(目标1)。我的实验室还成功地设计了与索洛奇尼亚小球藻的人工互作，提高了皮炎埃希氏菌的生存能力。我建议产生更多的相互作用，并用它们来定义真菌从光自养中获取营养的关键形态和代谢特征(目标2)。最后，我的实验室已经开始从加拿大的岩石表面和生物土壤结皮中收集大量耐极端真菌、藻类和蓝藻。我建议扩大和利用这个收集，以确定在多大程度上，光自养生物的“瞬时地衣化”代表了极端耐受性真菌在恶劣生态系统中确保营养的一般策略。我的研究计划将为多达12名HQP(2名博士、2名硕士、8名学士)提供强大的、尖端的培训体验。我们在今后五年的集体努力将产生前所未有的新见解，使我们了解适应环境的变化，这些适应扩大了可供真核生物殖民的陆地环境。