The underexplored microBiOme of phytOtelmata - a window towards the understanding of Significant ecological and evoluTive procEsses between the two chloRophototrophic life forms – BOOSTER

Chlorophototrophy is a key microbial innovation that has played a crucial role in the success of life on Earth. Attesting to the plasticity and diversity of chlorophototrophy, some microbes are able of photosynthesis without oxygen evolution. These anoxygenic phototrophic bacteria (APB), which use bacteriochlorophyll as their primary pigment, could play a pervasive role in the growth and survival of terrestrial plants. Indeed, in recent decades, APB have been added to the catalogue of microbial diversity inhabiting the phyllosphere (i.e. the aerial part of plants), one of the largest microbial habitats on Earth. However, previous studies have failed to address the ecology and functional role of APB communities in the phyllosphere, although many APB are also diazotrophic and could play a crucial role as indirect drivers of primary production.
BOOSTER will study the interactions between APB and terrestrial plants, focusing on the diazotrophic APB microbiome hosted in the phytotelmata of the common teasel, a plant widely distributed in Europe. These natural microcosms are relevant for these studies because they provide an environment conducive to interactions between the microbiome and APB, which are very abundant in these habitats. Furthermore, the APB microbiome could be selected by the teasel via a remarkable process, the ‘Pharaoh's snakes’, involving glandular hairs and retractable protrusive flaments, the nature of which remains unknown. BOOSTER will extend its studies to leaf surfaces in temperate regions and provide a high-throughput approach for establishing the distribution of APB and determining whether or not there is a core APB microbiome within the phyllosphere.
Using a coherent set of complementary cutting-edge approaches, BOOSTER will critically advance our understanding of plant-microbiome-APB interactions, and opens avenues for discovering novel strategies used by plants to tailor their associated nitrogen-fixing APB microbiota to their own needs.