BOTRYTISGENOMICS · Genomics of the Botrytis cinerea grapevine interaction

Genomics of the Botrytis cinerea grapevine interaction

The gray mold microscopic fungus Botrytis cinerea can attack more than 200 plant species, damaging their fruits, leaves, or flowers. Modern biology allows the investigation of the molecules that are recruited in the fungus cells for successful invasion of the plants. The discovery of key elements in the battle with the plant in turn can serve to find targets for the design of new and environment-friendly drugs for plant protection. The method called transcriptomics, where the activation level of thousands of genes can be simultaneously monitored in a little DNA chip, offer an effective way to perform such investigation and to find "needles of interest in a genomic haystack". When attacking the plant, the gray mold reproductive cell (spore) grows as a short filament which soon differentiates into a specialized structure that serves to enter the plant cell. During these early steps of the plant infection, the fungus is made up of only few cells and the amount of genetic material is therefore low. As a consequence, the collection of sufficient amounts of fungal sample for transcriptomics analysis is very difficult. Artificial surfaces like Teflon can mimic the plant leaves hydrophobic surfaces, and the researcher showed that they support the same successive early development stages of the gray mold as observed on grapevine leaves. Teflon membranes were hence used to produce large amounts of fungal material. This material was used in a DNA chip experiment. A second part of the researcher's work was dedicated to the study of one particular gene that had already been found activated during grey mould infection on mouse-ear cress (Arabidopsis thaliana) by using a small-scale transcriptomics approach (Gioti A et al, 2006). The goal was to explore the role of this unknown gene in the fungus life. To show the place in the cell where the protein product of this gene resides, this protein was flagged with a yellow fluorescent marker and then observed by using a fluorescent microscope. The distribution of the protein was not random, but appeared well limited in the cells. To investigate the role of the protein in the fungus life, mutants were produced in which the gene was removed. This absence caused a problem in the growth of the fungus filaments and in the production of spores. Moreover, the activity of the gene in the non-mutant fungus was found to be higher in the spores and at the filamentous stage. To identify all the genes whose activity is changed in the mutant when compared to the non-mutant fungus, a transcriptomic analysis was initiated. The data from these experiments will be available in 2011. The main results of this Marie-Curie project were 1) the production of genetic material necessary to find the gray mold genes that could be key factors in the early stages of the plant infection, and 2) the investigation of a so far unknown gene that is activated during plant infection. As both growth and reproduction of the fungus are affected in the absence of this gene, the initiated transcriptomic analysis will likely lead to very interesting new results. The practice of sustainable agriculture, using plant protection methods and chemicals which are less damaging to soil and water resources, has become a worldwide need. The fungicides that are being used help controlling the main fungal diseases of plants, but they represent an important cost, they cause environmental concerns, and they lead to the development of resistant strains. One of today's major socio-economical issue hence is the development of fungicides harmless for the environment. The research strategies that are ongoing today aim at developing fungicides with new and more selective action on the plant pathogens. As these strategies rely on a better understanding of the pathogens attack, the results of this Marie-Curie project represent an added value in the battle for a more environment-friendly agriculture.

Data: CORDIS, © European Union