H2020Индивидуална стипендия2018–2021

UCYN2PLAST · Exploring the mechanisms underlying the evolution of plastids through the study of an unusual nitrogen-fixing symbiosis

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2018-01-01 → 2021-11-01
Финансиране от ЕС: 246 668 €
Участници: 2
Схема: MSCA-IF

Линиите свързват координатора с партньорите.

Накратко на български

Симбиозата между морския алг Braarudosphaera bigelowii и азотфиксиращите бактерии UCYN-A се анализира като модел за развитие на пластидите. Това помага да се разберат механизмите, чрез които едноклетъчните организми се адаптират към бедни на азот среди и еволюират.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Exploring the mechanisms underlying the evolution of plastids through the study of an unusual nitrogen-fixing symbiosis

The proposed research in the UCYN2PLAST project was conceived to understand the evolution of intracellular plastids and niche adaptation processes of unicellular eukaryotes in nitrogen-limited environments such as the open ocean. Primary cyanobacterial-like plastids have experienced modifications in their genomes during the evolution towards a plastid lifestyle, but the underlying processes remain difficult to address because they occur over geological time scales. Thus, the study of present-day symbiotic associations between unicellular eukaryotes and prokaryotes might be an alternative way to understand how symbioses are established. A particular case of such symbiosis involves species closely related to the single-celled marine alga Braarudosphaera bigelowii (Prymnesiophyceae) and unicellular nitrogen-fixing cyanobacteria. This cyanobacterial symbiont, Candidatus Atelocyanobacterium thalassa (UCYN-A), is a widely distributed member of the marine plankton and a key player in the nitrogen cycle The parallelism between the endosymbiosis that originated the plastids in eukaryotes and the UCYN-A symbiosis makes this symbiosis a unique model to gain insight into the evolution of plastids, and further poses the question of whether we are currently witnessing an evolutionary process that will eventually lead to the establishment of a nitrogen fixing plastid. In this context, the UCYN2PLAST project was designed to explore the ecology and evolution of the UCYN-A nitrogen-fixing symbiosis as a way to better understand the mechanisms underlying plastid formation. Therefore, the overall objectives of the UCYN2PLAST project are: Objective #1 (outgoing phase): To identify and characterize new UCYN-A association trough microscopic and molecular techniques to gain insight into the evolution of the symbioses across lineages. Objective #2 (outgoing phase): To experimentally disentangle the temporal interplay between partners along a day-night cycle at three levels: whole-genome expression, nutrient assimilation, and metabolic exchange. Objective #3 (return phase): To explore the large-scale biogeography patterns in the distribution of these types of symbiotic associations across the global ocean and their underlying drivers.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

Symbioses are evident sources of innovation in nature, critical for the evolution of plastids and the success of eukaryotes on Earth. The mechanisms promoting such relationships, however, are difficult to identify, especially between single-celled organisms, and remain largely unknown. A widespread symbiosis was recently discovered in the ocean between an unicellular cyanobacterium (UCYN-A) and single-celled eukaryotic algae (prymnesiophyte). UCYN-A lacks typical cyanobacterial features such as the capacity to perform oxygenic photosynthesis, CO2 fixation or the tricarboxylic acid cycle, and must thus rely on the supply of organic matter from the algal host. In turn, UCYN-A shows a dramatic genome reduction with a high specialization in nitrogen fixation, providing fixed nitrogen to the alga. Given the importance of nitrogen for the algal productivity, it has been hypothesized that UCYN-A could eventually give rise to a nitrogen-fixing plastid in a process analogous to the origin of chloroplasts. This project aims to study the UCYN-A symbiosis both from an evolutionary and a functional point of view: First, the identification and characterization of new associations from marine samples at a global scale through molecular techniques will allow a deep comparison of closely-related symbiotic lineages that will help to understand the evolutionary underpinnings of this symbiosis. Second, nutrient incubation experiments of seawater samples over diel cycles will be performed to identify potential factors regulating the carbon and nitrogen exchange between partners to gain knowledge on the host-symbiont coupling mechanisms. For this purpose, metatranscriptomic analysis and electron microscopy combined with molecular probes and quantitative isotopic techniques (FISH-nanoSIMS) will be applied. Elucidating the mechanisms underlying this unusual nitrogen fixing symbiosis will provide valuable insight into previously unknown processes explaining the evolution of plastids

Оригинален текст от CORDIS (на английски).

Участници

SORBONNE UNIVERSITE · ParisКоординаторФранция
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA · OaklandСъединени щати