When roots talk, bacteria respond: Comparative transcriptomics of three plant growth-promoting rhizobacteria growing on root exudates reveals plant-specific responses
Year: 2026
Type: article
Abstract: In the rhizosphere, plant roots release rhizodeposits, including a complex mixture of molecules known as root exudates. These compounds mediate the recruitment of the rhizosphere microbiota, which plays a key role in plant growth and resistance to biotic and abiotic stresses. Deciphering the molecular dialogue between roots and their microbiota could promote the establishment of bioinoculants, such as plant growth-promoting rhizobacteria (PGPR), in the rhizosphere. Here, we investigated the genetic responses of three PGPR strains ( Bacillus subtilis ATCC 6633, Pseudomonas fluorescens ATCC 17400 and Azospirillum brasilense Sp245) to root exudates from rapeseed ( Brassica napus ), pea ( Pisum sativum ) and ryegrass ( Lolium perenne ). Transcriptomic analyses during PGPR growth on root exudates revealed that B. subtilis ATCC 6633 and A. brasilense Sp245 regulated the expression of hundreds of genes, while P. fluorescens ATCC 17400 appeared to already express most of the genes required for this response. Moreover, certain bacterial genes, mainly involved in metabolism, were regulated by all three exudates through a core transcriptome, while other genes were specifically modulated by each plant. Notably, rapeseed exudates stimulated amino acid metabolism, whereas pea exudates repressed motility and activated defense mechanisms. Finally, we deduced the amino acids and sugars present in root exudates and metabolized by PGPR. Together, our results highlight root exudate specificity in the recruitment of PGPR and could contribute to their establishment as bioinoculants for rhizosphere engineering.
Source: Rhizosphere
Institution: Université de Rouen Normandie
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: hybrid
Estimated APC paid: $2,970
Awards: G2588800179, G5465757707, G8367616569
OpenAlex ID: W7129491138