Project suggestion
Supervisor: Allan Rasmusson, Molecular Bioscience, Dept. Biology, LU
Many fungal species of the genus Trichoderma live in symbiosis with plant roots. The fungus produces substances that stimulate plant growth and immune system but also directly attacking other microorganisms, including pathogens. Therefore, some strains of Trichoderma have been used as biocontrol and biostimulants in agriculture, decreasing the need for agrochemical use. The effect of Trichoderma on plants is strongly dependent on the plant genome, which is involved in a mainly unknown intricate interaction with the fungus, likely involving exchange of several signalling biomolecules. Plant genes that are essential for biostimulation and biocontrol by fungi can be used in breeding, to make plants that can better benefit from biocontrol and biostimulation. However, we presently do not know what genes these are.
One possible class of genes that are essential for positive symbiosis with fungi are plant genes encoding proteins that are needed for the plants to avoid being damaged by the Trichoderma. This fungus attacks other microorganisms by secreting enzymes and peptide antibiotics, including so called peptaibols, where alamethicin is the standard model example. This peptide also lyses plant cells, but cellulase secreted from the Trichoderma induces resistance to the alamethicin by modifying the composition of the plant plasma membrane. This process we have named CIRA, and it is likely important for plant symbiosis with Trichoderma, though direct evidence are lacking. We have isolated CIRA-deficient mutants for 20+ Arabidopsis genes, indicating that a so far unknown response chain is active. The different mutants belong to the categories Gene expression, Cell wall modifying, Signalling, Membrane lipid modifying and “Unknown”. Identification and analysis of novel CIRA genes by mutant screening is a way to increase our knowledge of this process and possibly build a scheme for the involvement of the different genes.
Differently long projects (30-60 credits) can be designed within the area of:
- Analysis of particular known Arabidopsis mutants, their (lack of) biostimulation by Trichoderma, and the potential involvement of calcium signalling. Methodologically, this will involve at least sterile plant growth, fluorescent microscopy and measurements using intracellular fluorescent reporters.
- Identification and analysis of novel CIRA genes by mutant screening. Arabidopsis CIRA mutants are identified by a fluorescent phenotypic change and verified by designing PCR assays and analysing a second mutant allele for the same gene. The genes found are analysed in a first line by bioinformatic database mining (e.g. gene expression patterns, protein localisation, post-translational modification, etc). In a longer project additional analyses can be done. Acquired data will be used in order to assemble a preliminary signalling path.
For more information and discussions please contact allan.rasmusson@biol.lu.se
Most suitable background knowledge is molecular cell biology/molecular physiology with a focus on plants, yet with some understanding of plant interactions with other organisms.
Length of project: Flexible, a project of 30-60 credits can be designed.
Start date: To be discussed