Common Bean
Common Bean
Other Experts:
Microbiome of Common Bean
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 plant functioning, influencing its physiology and development. 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 in the rhizosphere microbiome to fend off infections and therefore does not need to develop genetic resistance.
In this project, common bean materials were selected, with a gradient of resistance to the pathogen Fusarium oxysporum, to understand how the host plant differentially shapes the structure of the rhizosphere microbiome. This proposal aimed to assess the microbial community inhabitant of the rhizosphere of common bean to identify potential microbial groups that support the plant to protect against the soil pathogen. Using a multi-omics approach, the structure, diversity, composition, and functional profile of microbial communities were characterized and compared to detect differences between the rhizosphere community of the resistant and susceptible plants. The results showed that breeding for resistance unintentionally co-selected for changes in rhizosphere microbiome composition and functions that may act in concert to restrict root infections. More specifically, the results showed that beneficial taxa such as Pseudomonas, Bacillus, and Paenibacillus, and antifungal traits such as protein secretion systems and biosynthesis of phenazines, rhamnolipids, and colicin V were enriched in the rhizosphere of the fox-resistant bean accession. Then, the integration of 16S-amplicon, shotgun metagenome as well as metatranscriptome sequencing with community ecology analysis showed that fox infections significantly changed the composition and gene expression of the root microbiome in a cultivar-dependent manner. More specifically, fox infection led to increased microbial diversity, network complexity, and a higher proportion of the genera Flavobacterium, Bacillus, and Dyadobacter in the rhizosphere of the fox-resistant cultivar compared to the fox-susceptible cultivar. In the endosphere, root infection also led to changes in community assembly, with a higher abundance of the genera Sinorhizobium and Ensifer in the fox-resistant cultivar. Metagenome and metatranscriptome analyses further revealed the enrichment of terpene biosynthesis genes with a potential role in pathogen suppression in the fox-resistant cultivar upon fungal pathogen invasion. Collectively, these results revealed a cultivar-dependent enrichment of specific bacterial genera and the activation of putative disease-suppressive functions in the rhizosphere and endosphere microbiome of common bean under siege.
