Skip to main content

LUP Student Papers

LUND UNIVERSITY LIBRARIES

Identification and functional characterization of novel genes involved in the Cellulase-Induced Resistance to Alamethicin (CIRA) pathway in Arabidopsis thaliana

Ruppert, Frédéric (2026) MOBM02 20252
Degree Projects in Molecular Biology
Abstract
Trichoderma are fungi that form symbiotic relationships with plant roots, representing an ecological topic for pest management. It offers a sustainable alternative to agrochemicals through biostimulation and biocontrol. However, the host plant needs to effectively manage a trade-off : using Trichoderma as a defense mechanism while not getting damaged by its cytotoxic compounds, like the antibiotic peptaibol alamethicin. To do so, the plant root developed a mechanism known as the Cellulase-Induced Resistance to Alamethicin (CIRA), that might include a signaling pathway. The project’s aim is to mainly elucidate CIRA, by identifying and functionally analyzing novel CIRA-deficient mutants in Arabidopsis thaliana. The project uses a mutant... (More)
Trichoderma are fungi that form symbiotic relationships with plant roots, representing an ecological topic for pest management. It offers a sustainable alternative to agrochemicals through biostimulation and biocontrol. However, the host plant needs to effectively manage a trade-off : using Trichoderma as a defense mechanism while not getting damaged by its cytotoxic compounds, like the antibiotic peptaibol alamethicin. To do so, the plant root developed a mechanism known as the Cellulase-Induced Resistance to Alamethicin (CIRA), that might include a signaling pathway. The project’s aim is to mainly elucidate CIRA, by identifying and functionally analyzing novel CIRA-deficient mutants in Arabidopsis thaliana. The project uses a mutant library screening and a Polymerase Chain Reaction (PCR) verification to identify and characterize novel CIRA genes, supported by phylogenetic and bioinformatics analyses. Better understanding of these new CIRA pathway components will be important to get a more complete comprehension of plant-Trichoderma interactions, which may strengthen modern agriculture techniques by better exploiting Trichoderma for enhanced growth and immunity. (Less)
Popular Abstract
The Plant’s Living Shield : A Molecular Secret Handshake

Imagine a plant that recruits a living shield to fight off pathogens, while simultaneously modifying its cellular structure to survive its protector’s toxic side effects.

In the rhizosphere, plant roots live in a complex symbiotic relationship with a beneficial fungus called Trichoderma. This fungus has a high potential in modern agriculture because it boosts plant growth and kills harmful pathogens. However, to wipe out its competitors, the fungus secretes an antibiotic called alamethicin. It creates holes in cell membranes, including those of the host plant. To make this partnership work, the plant has developed a defense mechanism called CIRA (Cellulase-Induced Resistance... (More)
The Plant’s Living Shield : A Molecular Secret Handshake

Imagine a plant that recruits a living shield to fight off pathogens, while simultaneously modifying its cellular structure to survive its protector’s toxic side effects.

In the rhizosphere, plant roots live in a complex symbiotic relationship with a beneficial fungus called Trichoderma. This fungus has a high potential in modern agriculture because it boosts plant growth and kills harmful pathogens. However, to wipe out its competitors, the fungus secretes an antibiotic called alamethicin. It creates holes in cell membranes, including those of the host plant. To make this partnership work, the plant has developed a defense mechanism called CIRA (Cellulase-Induced Resistance to Alamethicin).

Since global pesticide use has surged by 30% in the last two decades. We urgently need greener alternatives. By understanding the CIRA mechanism, we may breed crops that are better at collaborating with natural helpers like Trichoderma.

My work focused on understanding how Arabidopsis thaliana activates this defense. When the fungus approaches, it releases enzymes called cellulases. Instead of just seeing this as an attack on its cell walls, the plant uses these enzymes as a signal. It’s a molecular "secret handshake" that tells the plant: "Your ally is here; get your armor ready." In response, the plant reshapes its cellular structure, making it resistant to alamethicin.

To find the genes responsible for CIRA, I screened hundreds of mutant plants, each missing a single specific gene, to see which ones lost their ability to resist the toxin. If a plant cell’s plasma membrane got permeabilized after being treated with the fungus signal, it meant the missing gene was a vital piece of the defense machinery. My research identified five new candidate genes that orchestrate this defense. These genes aren't just doing one job; they coordinate a multi-layered response, from sending "orders" via genetic signals to physically transporting materials to reinforce the cell's borders.
According to the new genes identified, CIRA appears to be a very complex mechanism. It involves everything from internal scaffolding (tubulin) to stress-mediated proteins (peroxidases). By fully understanding CIRA, we could reduce our reliance on harsh chemicals and move toward a future where plants use their own natural "bodyguards" to stay healthy. This isn't just about one fungus and one plant; it's about unlocking the secrets of plant immunity to ensure food security in a changing climate.

Master’s Degree Project in Molecular Biology 30 credits 2026 Department of Biology, Lund University

Advisor: Allan Rasmusson
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Ruppert, Frédéric
supervisor
organization
course
MOBM02 20252
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9225715
date added to LUP
2026-04-23 17:47:35
date last changed
2026-04-23 17:47:35
@misc{9225715,
  abstract     = {{Trichoderma are fungi that form symbiotic relationships with plant roots, representing an ecological topic for pest management. It offers a sustainable alternative to agrochemicals through biostimulation and biocontrol. However, the host plant needs to effectively manage a trade-off : using Trichoderma as a defense mechanism while not getting damaged by its cytotoxic compounds, like the antibiotic peptaibol alamethicin. To do so, the plant root developed a mechanism known as the Cellulase-Induced Resistance to Alamethicin (CIRA), that might include a signaling pathway. The project’s aim is to mainly elucidate CIRA, by identifying and functionally analyzing novel CIRA-deficient mutants in Arabidopsis thaliana. The project uses a mutant library screening and a Polymerase Chain Reaction (PCR) verification to identify and characterize novel CIRA genes, supported by phylogenetic and bioinformatics analyses. Better understanding of these new CIRA pathway components will be important to get a more complete comprehension of plant-Trichoderma interactions, which may strengthen modern agriculture techniques by better exploiting Trichoderma for enhanced growth and immunity.}},
  author       = {{Ruppert, Frédéric}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Identification and functional characterization of novel genes involved in the Cellulase-Induced Resistance to Alamethicin (CIRA) pathway in Arabidopsis thaliana}},
  year         = {{2026}},
}