Crosstalk between Ca2+-signaling and the light-sensing pathway during stress responses and hyphal polar growth in Aspergillus nidulans and A. fumigatus

烟曲霉是世界范围内最重要的气传子囊菌病原体和过敏原之一。数百万人患有侵入性或慢性感染，每年导致超过60万人死亡。因此，更好地了解这种真菌的生物学可能有助于开发新的或改善现有的抗真菌药物在未来。真菌病原体必须适应各种体内障碍才能生存。这些障碍包括高温、pH变化、氧化应激或唑处理后的质膜应激。与其他丝状真菌一样，真菌病原体进化出许多信号转导系统来感知和响应环境胁迫，以在恶劣的环境条件下生存和增殖。HOG信号通路和Ca 2+信号通路都参与胁迫适应。最近，人们发现光敏色素通过HOG途径感受光信号，并且有证据表明光敏色素在植物和细菌中起着分子温度计的作用。在这个提议中，我们假设光敏色素依赖的光传感可能是通过HOG途径与Ca 2+信号转导相互关联的。我们的目的是在两个相关的子囊菌，构巢曲霉和条件致病性曲霉的两个信号通路的特点。烟熏。我们的初步数据还表明光敏色素和Ca ~（2+）信号通路都参与了A. nidulans。 我们计划研究光敏色素、HOG和Ca 2+信号通路在A. nidulans和A.烟熏。这两个信号通路之间的相互作用将在转录和转录后水平进行研究。还有很好的证据表明，Ca 2+不仅在胁迫适应中起作用，而且在极化生长中也起作用。结果表明，在极性菌丝延伸过程中，Ca 2+的浓度振荡，这种振荡可能是负责振荡的泡囊分泌，从而振荡生长的菌丝。由于应激反应引起细胞内Ca 2+浓度的显著变化，因此应激可能对极性细胞延伸产生影响。为了研究这种关系，我们将分析胁迫反应途径如何影响两种真菌的菌丝极性生长，以及它们如何影响A.烟熏。为了这个目的，我们将监测真菌细胞中的钙离子浓度的动态表达的钙报告水母发光蛋白结合荧光蛋白GECO技术，并研究对囊泡交通的影响。我们将应用超分辨率显微镜来观察菌丝中不同的囊泡群体，并记录它们的旅行路线，直到与顶膜融合。

Aspergillus fumigatus is one of the most important airborne ascomycete pathogens and allergen worldwide. Several million people have invasive or chronic infections that lead to >600,000 deaths every year. Hence, a better understanding of the biology of this fungus may help to develop new or improve existing antifungal drugs in the future. Fungal pathogens must adapt to a variety of in vivo obstacles to survive. These obstacles include high temperature, pH variation, oxidative stress or plasma membrane's stress upon azole treatment. As other filamentous fungi, fungal pathogens have evolved numerous signal-transduction systems to sense and respond to environmental stresses to survive and proliferate in harsh environmental conditions. The HOG pathway and the Ca2+ signaling pathway both are involved in stress adaptations. Recently, it was discovered that phytochrome senses the light signal through the HOG pathway, and there is evidence in planta and in bacteria that phytochrome plays a role as molecular thermometer. In this proposal we hypothesize that phytochrome-dependent light sensing might be interlinked with Ca2+ signaling via the HOG pathway. We aim at characterizing the two signaling pathways in two related ascomycetes, Aspergillus nidulans and the opportunistic pathogenic A. fumigatus. Our preliminary data also indicate both phytochrome- and the Ca2+-signaling pathway are involved in thermo-sensing in A. nidulans. We plan to study the role of phytochrome, the HOG and the Ca2+ signaling pathway in temperature and azole antifungal sensing in A. nidulans and in A. fumigatus. The interaction between the two signaling pathways will be studied at the transcriptional and the posttranscriptional level. There is also good evidence that Ca2+ not only plays a role in stress adaptation, but also in polarized growth. It was shown that the concentration of Ca2+ oscillates during polar hyphal extension and that this oscillation may be responsible for oscillations of vesicle secretion and thus oscillatory growth of hyphae. Because stress responses cause dramatic changes of the intracellular Ca2+ concentration, effects of stress on polar cell extension are likely. To study this relationship, we are going to analyze how stress-response pathways affect hyphal polar growth in both fungi and how they affect virulence in A. fumigatus. For this aim, we will monitor the dynamics of the Ca2+ concentration in fungal cells expressing the calcium reporter aequorin combined with fluorescent protein GECO technologies and study the effect on vesicle traffic. We are going to apply super-resolution microscopy to visualize different vesicle populations in the hyphae and document their travel routes until fusion with the apical membrane.