Rhizosphere microbiome of common bean resistant to the soil pathogen Fusarium oxysporum

Abstract

The rhizosphere is considered one of the most dynamic interfaces of the world, constituting a hot spot of microbial activity. The rhizosphere microbiome plays a key role in the functioning of plant, influencing its physiology and development. Although the importance of rhizosphere microbioma for plant growth has been widely known, for the vast majority of rhizosphere microorganisms there is no information. To enhance plant growth and health, it is essential to know which organisms are present in the rhizosphere microbiome and what they are doing. Whereas examples of genetic plant resistance to soil diseases are rarer than resistance to pathogens of the shoots, it has been suggested that the plant uses mechanisms present in the rhizosphere microbiome to fend off infections and therefore do not need to develop genetic resistance. Thus, in this study it will be selected bean materials with a gradient of resistance to the pathogen Fusarium oxysporum, i.e. resistant, susceptible and intermediate materials, to understand how the host plant differentially shapes the structure of the rhizosphere microbiome. This proposal aims to assess the microbial community inhabitant of the rhizosphere of common bean in order to identify potential microorganisms groups that support the plant to protect against the soil pathogen. For this, cultivars resistant and susceptible to the pathogen will be grown in greenhouse experiments using two soil types, one with high microbial diversity (Amazon Dark Earth) and an agricultural soil. The community assessment will be done through classical microbiology approaches and molecular biology. Initially, isolation and antagonism tests will be carried out to detect groups that promote protection of the plant against the fungus. After, with a molecular approach, the structure and diversity of microbial communities will be characterized by high-throughput sequencing and then compared to detect differences between the rhizosphere community of the resistant and susceptible plant. The data will be analyzed by bioinformatics tools and multivariate statistical analyzes, gathering information about the structure and composition of the communities, and soil physic-chemical data. This project seeks to understand and detect changes in the rhizosphere microbiome driven by the resistance of the plant to the pathogen, and what the relationship of microorganisms in this process. Considering the importance of soil microorganisms in biogeochemical cycles, as well as in plant-pathogen interaction, the approach of a study focused on microbial ecology is urgently needed for the development of new methods that promote the health and growth of plants. The data obtained in this study will be useful to increase our knowledge about the role of the rhizosphere microbiome and use this new information to build a more sustainable use of the ecosystem.