Cryptochrome photoreceptors in the green alga Chlamydomonas reinhardtii: Versatility of functions and mechanisms

微藻生活在海洋、淡水和/或潮湿的土壤中。它们对全球碳固定做出了重大贡献，是食物网的基础。为了应对水柱中不同强度和质量的光，他们开发了大量具有新功能和新机制的光感受器。双鞭毛藻绿色单细胞藻衣原体几十年来一直是研究光驱动过程的模型，因为它可以转化，遗传杂交是可能的，比如与面包师的酵母。光影响它的行为，它的生命周期，光合作用，并通过明暗循环同步它的生物钟。莱茵梭子藻有18种不同的光感受器，从其中一些我们还不知道任何功能或作用机制。这些受体中有四个属于隐色素(CRY)家族，该家族源于DNA修复酶(光解酶)，包括在高等植物中发现的典型的植物哭声(PCRY)、动物样的哭声(ACRY)以及两个破折号样的哭声。在这项建议中，我们的目标是进一步研究绿藻隐色素的功能和机制。我们感兴趣的是：(A)藻类有性周期中aCRY的降解机制及其对生活史的影响；(B)pCRY在夜间的相互作用伙伴(S)及其对昼夜节律和/或生命周期的调节作用；以及(C)这两个cYR-DASH的功能。插入敲除突变体和已知突变体可用于此目的，CRISPR/Cas9方法可用于产生更多突变体。我们想要了解不同的隐花色素光感受器及其不同的吸收光谱是如何控制藻类生命的，目的是揭示不同的隐花色素的重叠和不同的功能。

Microalgae live in the ocean, freshwater and/or wet soil. They contribute significantly to global carbon fixation and are at the basis of food webs. To cope with the different intensities and qualities of light in the water column, they developed a large variety of photoreceptors with novel functions and mechanisms. The biflagellate green unicellular alga Chlamydomonas reinhardtii serves since decades as a model to study light-driven processes, since it can be transformed and genetic crosses are possible such as with baker’s yeast. Light influences its behavior, its life cycle, photosynthesis and synchronizes its circadian clock by light-dark cycles. C. reinhardtii has 18 different putative photoreceptors and from some of them we do not know any function or mechanism of action. Four of these receptors belong to the cryptochrome (CRY) family that derives from DNA repair enzymes (photolyases), including a typical plant CRY (pCRY) as found in higher plants, an animal-like CRY (aCRY) as well as two DASH-like CRYs. In this proposal, we aim to study further the functions and mechanisms of the green algal cryptochromes. We are interested in (a) the mechanism of degradation of aCRY during the sexual cycle of the alga and its influence on the life cycle as well as in (b) the interaction partner(s) of pCRY in the night and their contribution to circadian and/or life cycle regulation as well as in (c) the functions of the still elusive roles of the two CRY-DASHs. Insertional knock-down and know out mutants are available for this purpose and CRISPR/Cas9 approaches can be used for generating further mutants. We want to understand how the variety of cryptochrome photoreceptors along with their different absorption spectra controls algal life and aim to reveal the overlapping as well as the distinct functions of the different cryptochromes.