Chloroplasts, the powerhouses of plant cells which make food by photosynthesis, are known to re-position themselves to make the most of the Sun's energy. Now, research carried out at CLF's Octopus facility, and published in The Plant Journal, has shown the role of chloroplasts in the plant's immune system, travelling around cells to respond to infection. The research team, from Imperial College London, Bristol University, The Turing Institute, Martin-Luther-Universität Halle-Wittenberg, and Ciudad Autónoma de Buenos Aires, hope this could offer an exciting avenue to develop plants which are more resistant to infection and help prevent potential disease-led food shortages.
The team used the plant pathogen Pythophthora Infestans in their investigation, a fungus-like organism now known to have triggered the Irish and Highland 'potato famines'. Between 1845 and 1852, more than 1 million people living in Ireland lost their lives due to starvation (out of a population of just 8 million). Another 2.1 million people left the island of Ireland, emigrating mainly to the UK and the US. The population of Ireland only returned to pre-famine levels in 2016. Understanding the role of chloroplasts in the plant immune response may contribute to making a future economic and human catastrophe on such a scale less likely.
Using Total Internal Reflection Fluorescence (TIRF) Microscopy and time lapse video, the investigators observed a larger number of chloroplasts in proximity to the specialised membrane that forms an interface between the plant cell and the invading pathogen. By trying to move the chloroplasts away from the pathogen interface using laser tweezers, the experiment showed an association between chloroplasts and the pathogen interface;
Just like tweezers you might use to remove a splinter, laser tweezers allow you to pick up very small objects and move them in a precise and controlled way. Except, laser tweezers can manipulate objects on the nanometre scale, using a highly-focused laser beam – including individual organelles, such as chloroplasts. Facilities like Octopus mean researchers from across all disciplines are able to access these techniques, with support from CLF's specialists.
Dr Tolga Bozkurt, Senior Lecturer in the Department of Life Sciences at Imperial College, said, “The opportunity to gain access to TIRF-Tweezers microscope have been a game changer for the project. Without the optical tweezer technology we would not be able to uncover the associations with the chloroplasts and the enigmatic plant-pathogen interface membrane, as there is not any established method to isolate this membrane. Our experience using the facilities has been great. We had continuous support from the staff and researchers to run the assays smoothly while making sure that appropriate safety precautions are at place."
Read the full paper at: https://doi.org/10.1111/tpj.15416.