Institute of Plant Biology

Blue-green bacteria are the oldest known species that can produce oxygen through photosynthesis. It appeared about 3.5 billion years ago. It is very likely that it was the culprit that caused the Great Oxygenation Event 2.4 billion years ago and caused a large number of deaths of anaerobic bacteria. , But also created the subsequent biological energy to use oxygen for respiration and the emergence of eukaryotic multi-cells. Today’s complex species diversity is really thanks to the small blue-green bacteria that produced oxygen in the ocean at the beginning!

Scientists' research on blue-green bacteria ranges from basic research to application level, which can be said to be very diverse. I hope that during my time at the Institute of Plant Science, I can discuss three topics in depth: (1) the role of blue-green bacteria in the ecosystem (2) the mechanism of far-red photosynthesis (3) the application value of blue-green bacteria.

Blue-green bacteria grow in a wide range, from the ocean to the land, and even in extreme climates such as deserts, hot springs and Antarctica, they can be found. Taiwan’s geographic environment, including humidity and temperature, are suitable for the growth of blue-green bacteria in the terrestrial ecosystem, and because of the isolation of the ocean, the blue-green bacteria in the land’s freshwater are very likely to evolve unique traits, and Taiwan has hot springs Special environments such as places are excellent places to study blue-green bacteria in the environment. I hope that in these geographical environments in Taiwan, we can combine metagenomics, strain isolation, and physiological growth analysis to study the strategies and methods of blue-green bacteria in these environments to adapt to the environment.

Far-red light is an important energy in sunlight, but few species can use far-red light to produce oxygen through photosynthesis, and the blue-green bacteria we studied is one of them. People have not believed that far-red light can catalyze photosynthesis to release oxygen. Our purpose is to let the public understand the productivity and importance of Far Hongguang in the environment, and then re-evaluate the global primary productivity. In addition to the study of promoters regulated by far-red light, which can provide a tool for synthetic biology, clarifying the ability of blue-green bacteria to use far-infrared light is more helpful to maintain the efficiency of photosynthesis in the absence of visible light in the bioreactor. Increase the output of synthetic biomass energy or high-priced products. Our ultimate goal is to transfer the system that uses far-red light to crop crops to help them absorb more light under mutual shading, thereby increasing the efficiency and yield of photosynthesis.

background knowledge

When it is difficult to receive visible light, the use of far-red light for photosynthesis is a very important mechanism for blue-green bacteria.

Some blue-green bacteria can use far-red light for photosynthesis to release oxygen when there is insufficient visible light. This mechanism is called far-red light conversion (FaRLiP). Far-red light conversion will produce chlorophyll d and chlorophyll f, and modify photosynthetic system one, photosynthetic system two and phycobiliprotein bodies to absorb far-red light. These genes form a far-red light gene cluster, and their performance is regulated by the photosensitizers RfpA, RfpC, and the transcription factor RfpB.