Award details

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

Reference	BB/X010651/1
Principal Investigator / Supervisor	Dr Joseph McKenna
Co-Investigators / Co-Supervisors
Institution	University of Warwick
Department	School of Life Sciences
Funding type	Research
Value (£)	406,515
Status	Current
Type	Fellowships
Start date	01/06/2023
End date	31/05/2026
Duration	36 months

Abstract

Organelle dynamics underpin fundamental processes necessary for life in all organisms. In plants, the secretory pathway (ER and Golgi bodies), nucleus and plastids show high mobility within the cell. This movement is driven by the actin. If actin is perturbed then organelle movement stops. Moreover, if chimeric myosin motor proteins with faster motor domains are expressed, plant biomass increases. Therefore, organelle dynamics have a fundamental role on plant growth and development as well as biotic and abiotic stresses and could be harnessed to improve food security. Remarkably no myosin labels an organelle membrane (except for the nucleus) and no adapter proteins have been identified which interact with both myosin and organelles (except for the Golgi). Therefore, we do not understand how actin interacts with most organelles to drive dynamics. My hypothesis is that specific interactions between the actin cytoskeleton and organelles drive these dynamics and that the proteins governing these interactions can be engineered to fine-tune plant growth. To test this, I will use state-of-the-art microscopy and proximity labelling proteomics to achieve the following objectives: 1: Elucidate the spatial and temporal contact sites between the actin cytoskeleton, ER and nuclear membranes. 2: Identify the molecular machinery involved in actin-ER and actin-nucleus connections 3: Engineer Actin-ER interactions to regulate biomass and generate climate smart plants. Outputs of this fellowship will be: 1) Settling the debate of how the actin cytoskeleton drives organelle dynamics, specifically the ER. 2) Engineering actin-ER interactions to fine-tune plant growth and generate climate smart plants which can be translated for sustainable enhancement of agriculture 3) The establishment of myself as a leader in the field of actin-organelle interactions in plants and significant career momentum generated to attract follow on funding and growth of my own research group.

Summary

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.

Committee	Research Committee B (Plants, microbes, food & sustainability)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	Fellowship - David Phillips Fellowship (DF) [1995-2015]
Funding Scheme	X – not Funded via a specific Funding Scheme

I accept the terms and conditions of use (opens in new window)

export PDF file

back to list new search