Endophytic bacteria within the green siphonous seaweed Bryopsis: exploration of a partnership

“Life did not take over the globe by combat, but by networking” (Lynn Margulis - evolutionary biologist). Life itself is contained in this one sentence. Besides Darwin's famous ‘natural selection' theory, symbiosis, the cooperation between different organisms, is necessary for the survival and evolution of species. Looking at a human being, an animal, or a plant. They all tell the same story. Everything works according the same holistic principle of interconnection and cooperation. Also seaweeds undertake close collaborations with external and internal bacteria. Seaweeds are an unlimited source of oxygen and sugars which bacteria are happy to take advantage of. In exchange for these nutrients, bacteria produce growth promoting minerals and vitamins and they protect their host against environmental threats. As a result, many seaweed-bacterial associations are essential for both symbiotic partners. This dissertation takes you on an exploratory trip to the hows and whys of the exciting partnership between the feathery-like alga Bryopsis and bacteria inside this green seaweed. I hope that, while reading between the lines, I can tell you a story about the power of collaboration. Not between two, but a lot of partners. Each with their own talents and flaws. Each in their own way. “It takes two to tango, but a whole crowd to stage dive!”