The ties that bind: Understanding actin-organelle interactions in planta.

点击翻译按钮获取中文摘要

Plants are the basis of food security and energy / CO2 capture on planet earth. We face a major challenge with climate change and population growth meaning we need to grow 60% more food by 2050 in a period where both cold and warm temperature shocks are occurring with increased frequency. Therefore, novel insights into harnessing plant growth based on fundamental discoveries are required. At the cellular level plants display some of the fastest movements known in biology such as cytoplasmic streaming in algae. Organelles within plants including the nucleus, ER and Golgi bodies show rapid and coordinated movements within plant cells. This movement is critical for normal growth and development as well as responses to environmental conditions. Organelles are known to change shape and move according to certain stresses, including hot or cold temperature stress. However, we do not know the exact mechanism of how this movement occurs although we know it is driven by the actin cytoskeleton and myosin motor proteins. Actin is an intricate filamentous network in the cortex of plant cells. Which if disrupted, organelle movement stops. However, we do not yet understand how the actin cytoskeleton interacts with the organelles, driving movement within the cell. I will uncover how the ER and nucleus interact with the actin cytoskeleton. The ER is known to rapidly remodel during normal development and plant stress and the nucleus is highly mobile and its interaction with the actin cytoskeleton is known to regulate genome organisation and transcription. If we can understand how actin interacts with these organelles and the proteins involved, we can engineer these systems to improve plant growth and develop plants which are resistant to temperature stresses.To answer these challenges, we first need to be able to see the specific interactions between actin and these organelles. How exactly does the actin cytoskeleton interact with them? I have adapted and validated a fluorescent reporter which allows only actin interaction at the organelle membrane to be imaged, not the rest of the actin network. This will allow me to characterise precisely how the cytoskeleton interacts with these organelles and how this changes during normal and stress induced organelle movement. This will be transformational for our understanding of organelle dynamics in plants. Expanding on this novel approach, I will use a recently developed technique called proximity labelling that allows identification of proteins located at these contact sites between actin and an organelle. By identifying and characterising the proteins which control these interactions I will be able to determine exactly how actin drives mobility of these organelles. It is known that changing the rate of organelle dynamics has a direct effect on plant growth. Faster movement results in larger plants. As such, I will harness and engineer actin-ER interactions to fine-tune plant growth and generate climate smart plants which are resistant to temperature shocks, therefore sustainably enhancing agriculture.