Characterization of Pythium oligandrum populations that colonize the rhizosphere of vines from the Bordeaux region

cited By 2International audienceThis study focused on one oomycete, Pythium oligandrum, well-known for its plant protection abilities, which thrives in microbial environment where bacteria and fungal communities are also present. The genetic structures and dynamics of fungal and bacterial communities were studied in three Bordeaux subregions with various types of soil, using single-strand conformation polymorphism. The structure of the fungal communities colonizing the rhizosphere of vines planted in sandy-stony soils was markedly different from that those planted in silty and sandy soils; such differences were not observed for bacteria. In our 2-year experiment, the roots of all the vine samples were also colonized by echinulated oospore Pythium species, with P. oligandrum predominating. Cytochrome oxidase I and tubulin gene sequencings showed that P. oligandrum strains clustered into three groups. Based on elicitin-like genes coding for proteins able to induce plant resistance, six populations were identified. However, none of these groups was assigned to a particular subregion of Bordeaux vineyards, suggesting that these factors do not shape the genetic structure of P. oligandrum populations. Results showed that different types of rootstock and weeding management both influence root colonization by P. oligandrum. These results should prove particularly useful in improving the management of potentially plant-protective microorganisms. Pythium oligandrum strains with elicitor genes frequently colonize grapevine rhizosphere and the genetic structure of strains is not shaped by the abiotic and biotic factors studied in three Bordeaux sub-regions. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved

Biological control of plant pathogens: Advantages and limitations seen through the case study of Pythium oligandrum

cited By 16International audienceThe management of certain plant beneficial microorganisms [biological control agents (BCAs)] seems to be a promising and environmental friendly method to control plant pathogens. However, applications are still limited because of the lack of consistency of BCAs when they are applied in the field. In the present paper, the advantages and limitations of BCAs are seen through the example of Pythium oligandrum, an oomycete that has received much attention in the last decade. The biological control exerted by P. oligandrum is the result of a complex process, which includes direct effects through the control of pathogens and/or indirect effects mediated by P. oligandrum, i.e. induction of resistance and growth promotion. P. oligandrum antagonism is a multifaceted and target fungus-dependent process. Interestingly, it does not seem to disrupt microflora biodiversity on the roots. P. oligandrum has an atypical relationship with the plant because it rapidly penetrates into the root tissues but it cannot stay alive in planta. After root colonisation, because of the elicitation by P. oligandrum of the plant-defence system, plants are protected from a range of pathogens. The management of BCAs, here P. oligandrum, is discussed with regard to its interactions with the incredibly complex agrosystems. © 2013 Springer-Verlag Berlin Heidelberg

Control of a fungus involved in grapevine trunk disease (Esca) by using the oomycete, Pythium oligandrum : analysis of the induced resistance

International audienc

Grapevine and trunk pathogen transcriptomic changes induced by the root biocontrol agent Pythium oligandrum

Trabajo presentado en el 10th International Workshop on Grapevine Trunk Diseases, celebrado en Reims (Francia), del 4 al 7 de julio de 2017Peer reviewe