在水生食肉植物Utricularia reflexa的捕蟲器中，發現了Tetrahymena（四膜）屬中唯一的綠色纖毛蟲Tetrahymena utriculariae。該纖毛蟲與微藻Micractinium tetrahymenae形成內共生關係，藻類在捕蟲器的厭氧環境中為纖毛蟲提供氧氣和其他光合產物，而纖毛蟲則為藻類提供保護，使它們免受掠食者的侵害。本研究旨在建立T. utriculariae與各種藻類之間的穩定內共生關係，並了解它們的代謝交互作用。此外，T. utriculariae具有獨特的非孟德爾機制，在食物匱乏期間選擇表達哪種交配型，但交配型決定的詳細分子途徑仍不清楚。內共生研究表明，T. utriculariae與其藻類內共生體之間的相互作用始於共生關係的胚胎階段，並且T. utriculariae能夠與多種藻類品系形成互利關係，尤其是Chlorella variabilis和Didymogenes-sphaerica類品系。當暴露於光下時，纖毛蟲與綠藻的內共生關係可以使其在厭氧條件下存活。此外，我們還以Tetrahymena屬的DRB3基因建立了幾個構築，旨在降低或剔除T. utriculariae關鍵代謝途徑中必要基因的表現量，為後續驗證藻類內共生體對纖毛蟲宿主在內共生過程中的影響建立系統。關於交配型決定研究，我們嘗試建立來自T. utriculariae微核的交配型基因對的構築，纖毛蟲的交配型是否影響其與藻類的內共生關係仍待進一步研究。;Tetrahymena utriculariae, the only recognized green ciliate within the Tetrahymena genus, was found in the traps of the aquatic carnivorous plant Utricularia reflexa. It forms an endosymbiotic relationship with the microalga Micractinium tetrahymenae, wherein the algae provide oxygen and other photosynthates to the ciliate in the anaerobic environment of the trap lumen, whilst the ciliate offers a protective habitat for the algae, shielding them from predators. This study aimed to establish a stable endosymbiotic relationship between T. utriculariae and various algae, examining their metabolic interactions. Moreover, T. utriculariae has a unique non-Mendelian mechanism to choose which mating type is expressed after conjugation during food scarcity, but the detailed molecular pathways underlying mating type determination (MTD) remain elusive. The study on endosymbiosis revealed that interactions between T. utriculariae and its algal endosymbionts begin at the early stage of their symbiotic relationships and T. utriculariae can form mutualistic relationships with various algal strains, especially Chlorella variabilis and Didymogenes-sphaerica¬-like strains. These relationships can extend the survival of the ciliates under anaerobic conditions when exposed to light. Furthermore, we also created several constructs inserted into the DRB3 gene of Tetrahymena utriculariae with the aim of knocking out specific genes and generating fusion proteins with a fluorescent marker. It paves the way for dissecting the genetic basis of endosymbiosis. For the MTD study, we try to create several constructs of mating type gene pairs collected from T. utriculariae‘s micronuclei. Demonstrating whether any of the particular mating types of ciliates favor their endosymbiosis with algae requires further studies.
