ABSTRACT: The success of plant growth-promoting rhizobacteria (PGPR) as biofertilizers depends on their ability to attach to, colonize, and persist on plant roots under dynamic environmental conditions. In this seminar, I will present our work on the mechanisms governing early PGPR-root interactions across multiple experimental platforms. Using AFM-based single-cell force spectroscopy, we investigated the primary attachment of individual bacterial cells to different regions of Arabidopsis thaliana roots and identified strain-specific adhesion strategies mediated by long surface polymers, flagella, and physicochemical interactions, including electrostatic and hydrophobic forces. To extend these findings to flow-based environments, we developed a microfluidic root-on-a-chip system that enables real-time monitoring of bacterial accumulation on living roots under continuous flow. Using this platform, we found that both shear conditions and divalent ions influence early bacterial attachment kinetics. I will also discuss how positively charged nanoplastics disrupt these beneficial interactions by coating bacterial surfaces, reducing viability, and inhibiting root colonization. Together, this work provides mechanistic insight into how beneficial bacteria establish on plant roots and how environmental conditions and contaminants shape this process.

HOST: Keiko Yoshioka

LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432

LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/

by Anna Kozelj

Last day to drop Winter (S) courses

by Genna Zunde

François Bordeleau, PhD - Faculty of Medicine, Université Laval -- CSB Seminar

CSB Departmental Seminar

Friday, March 20th @ 11:00 am

SPEAKER: François Bordeleau, PhD - Faculty of Medicine, Université Laval

TITLE: Mechanotransduction in cancer cells – when the cells know what is best for them

ABSTRACT: The gradual stiffening over time of the tumor stroma has been associated with the metastatic progression during cancer. Cellular processes associated with metastatic potential, such as contractility and migration, are impacted by the evolution of the tumoral stroma. However, how tumor cells can adapt to these changes to drive metastasis remains largely unknown. I will present ongoing work from my lab aimed at uncovering what modulates tumor cells’ responses to an altered tumor stroma and how it relates to their aggressiveness. To investigate the differential regulation of mechanosensing in relation to the invasive potential of cancer cells, we combine tissue engineering approaches, animal models, bioinformatics and quantitative analysis. Using these approaches, we are uncovering a fundamental role for alternative splicing events as molecular sensors that fine-tune the ability of cells to respond to substrate stiffness. Our work has also expanded to cells’ response to different ECM compositions. Overall, our research defines critical mechanisms that could help identify cancers at risk of quickly evolving toward an aggressive disease.

HOST: Sergey Plotnikov

LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432

LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/

by Anna Kozelj