Could you give us some background information concerning your project, and why it is important?
My name is Julie Gervais and I am a third year PhD student in INRA BIOGER (France) working on a fungal pathogen of oilseed rape, Leptosphaeria maculans, which is responsible for the stem canker disease. This fungus has two colonization stages of the plant. During the first stage, the fungus infects leaves and cotyledons (the first leaves to appear from a germinating seed). Once in the leaves, the fungus has a short biotrophic stage of 10 days and then switches to necrotrophy.
Following this primary leaf infection, L. maculans grows inside the stem tissues during a long endophytic systemic colonization. This colonization is completely symptomless and may last up to 9 months. I am aiming to gain a better understanding of how the fungus can grow inside the oilseed rape stem for several months without causing any symptoms. I am particularly focused on the identification of new effectors, secreted proteins, produced by the fungus enabling it to develop itself efficiently into the plant.
Could you briefly describe your research and your findings?
I am particularly focused on the identification of new effectors, secreted proteins, produced by the fungus enabling it to develop itself efficiently into the plant.
By transcriptomic analysis, I identified ‘late’ effector candidates, under-expressed in the early colonization stage and over-expressed in the infected stems. My analysis revealed a link between the regulation of expression of effectors and their genomic location: the ‘late’ effector candidates, putatively involved in systemic colonization, are located in gene-rich genomic regions, whereas the ‘early’ effector genes, over-expressed in the early colonization stage, are located in gene-poor regions of the genome. These results were recently published in an article of Molecular Plant Pathology.
I am also trying to confirm the role of effector for six late effector candidates: I am measuring the impact of the silencing of these genes on the fungal growth inside the stem. Preliminary results indicated that the silencing of one of these candidates induced smaller necrosis on the stem.
Another aim of my thesis is to identify new resistances to control L. maculans. The identification of new effector genes would contribute to the identification of new resistance genes specific to these effectors.
What brought you to work with fungi? And what do you enjoy most about your research?
During my studies, I became more interested in the understanding of interactions between plants and micro-organisms, so I decided to pursue this interest in my thesis on L. maculans and its host, oilseed rape. I especially enjoy trying to dissect the network of interactions between the two organisms and to be able to apply such findings in the effective control of plant diseases.
What advice would you give young scientists starting out in research?
I would advise young scientists to stay focused on what they are interested in and to always take pleasure in what they do. Science is fun!
I was able to attend to the Fungal Genetics Conference thanks to travel fundings from the « Académie d’agriculture (grant Jean & Marie-Louise Dufrenoy)» and from the Genetics Society of America.
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