Periodic Reporting for period 2 - COSI (Understanding organelle communication through contact sites in plant stress responses)
Reporting period: 2022-08-01 to 2024-01-31
• What is the problem/issue being addressed?
As plants are sessile organisms, they have to adapt to constantly changing and often harmful environmental conditions, such as drought, increased temperatures, extreme light intensities, and attacks by pathogens. Therefore, plants have evolved complex mechanisms at the cellular and molecular level to respond to these stresses. Plant cells can sense environmental stimuli at the cellular surface and, therefore, several studies have focused on identifying abiotic stress sensors and pathogen receptors at the plasma membrane. In addition, organelles within the plant cell such as chloroplasts, mitochondria and the ER play a pivotal role in sensing and integrating stress signals into adaptive responses. However, it remains not understood how these organelles can communicate with each other. In the COSI project we will investigate a novel communication mechanism by the formation of physical contact sites between organelles.
• Why is it important for society?
Our global food security is and will be further challenged by extreme environmental conditions that severely affect crop productivity. To breed or engineer crops with increased performance during unfavorable growth conditions, a fundamental understanding of how plants respond to and try to cope with these stress conditions is required. In the COSI project, we aim to tackle this question by understanding at the molecular level how plant cells go from perceiving stress signals to launching appropriate stress responses.
• What are the overall objectives?
The overall aim of the COSI project is a better understanding of the fundamental mechanisms by which plants respond and adapt to stresses. We will investigate the mechanisms on how organelles within the cell sense and convey stress signals by the formation of contact sites. To meet these objectives, we will first assess under which stress conditions inter-organelle contact sites are formed. Secondly, by the identification and characterization of the molecular components that are present at these contact sites, we will obtain insight into their specific functions during plant stress responses.
As plants are sessile organisms, they have to adapt to constantly changing and often harmful environmental conditions, such as drought, increased temperatures, extreme light intensities, and attacks by pathogens. Therefore, plants have evolved complex mechanisms at the cellular and molecular level to respond to these stresses. Plant cells can sense environmental stimuli at the cellular surface and, therefore, several studies have focused on identifying abiotic stress sensors and pathogen receptors at the plasma membrane. In addition, organelles within the plant cell such as chloroplasts, mitochondria and the ER play a pivotal role in sensing and integrating stress signals into adaptive responses. However, it remains not understood how these organelles can communicate with each other. In the COSI project we will investigate a novel communication mechanism by the formation of physical contact sites between organelles.
• Why is it important for society?
Our global food security is and will be further challenged by extreme environmental conditions that severely affect crop productivity. To breed or engineer crops with increased performance during unfavorable growth conditions, a fundamental understanding of how plants respond to and try to cope with these stress conditions is required. In the COSI project, we aim to tackle this question by understanding at the molecular level how plant cells go from perceiving stress signals to launching appropriate stress responses.
• What are the overall objectives?
The overall aim of the COSI project is a better understanding of the fundamental mechanisms by which plants respond and adapt to stresses. We will investigate the mechanisms on how organelles within the cell sense and convey stress signals by the formation of contact sites. To meet these objectives, we will first assess under which stress conditions inter-organelle contact sites are formed. Secondly, by the identification and characterization of the molecular components that are present at these contact sites, we will obtain insight into their specific functions during plant stress responses.
1. As a first achievement of COSI, we have generated a molecular toolbox to enable to visualize contact sites between mitochondria, chloroplasts and the ER in living plant cells. These transgenic plant lines will be used to screen for physiological and pharmacological stress conditions that induce contact site formation between organelles.
2. Secondly, we have generated a molecular toolbox that will enable us to characterize the proteome (or protein components) at inter-organelle contact sites. Identification of the molecular players, including regulatory and functional components, at contact sites will provide us with novel knowledge on the function of contact sites in plants during unfavorable (stress) conditions.
2. Secondly, we have generated a molecular toolbox that will enable us to characterize the proteome (or protein components) at inter-organelle contact sites. Identification of the molecular players, including regulatory and functional components, at contact sites will provide us with novel knowledge on the function of contact sites in plants during unfavorable (stress) conditions.
Progress beyond the state of the art and expected results until the end of the project
Overall, the project will provide novel knowledge on when (under which conditions) and how (which molecular components) contact sites are formed between plant organelles (mitochondria, chloroplasts and the ER). To accomplish this, we will first use the molecular tools that we have obtained in this project to visualize contact sites in plant cells in response to various stress conditions. Additionally, we are implementing and optimizing alternative methods to enable to visualize contact site formation dynamics, including the formation and dissociation of contact sites. Secondly, using our proteomics setup, we will identify contact site protein components and characterize their function during plant stress conditions.
Overall, the project will provide novel knowledge on when (under which conditions) and how (which molecular components) contact sites are formed between plant organelles (mitochondria, chloroplasts and the ER). To accomplish this, we will first use the molecular tools that we have obtained in this project to visualize contact sites in plant cells in response to various stress conditions. Additionally, we are implementing and optimizing alternative methods to enable to visualize contact site formation dynamics, including the formation and dissociation of contact sites. Secondly, using our proteomics setup, we will identify contact site protein components and characterize their function during plant stress conditions.