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.
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Claims 9
Claim · model-written summary
B. subtilis ATCC 6633 regulated the expression of hundreds of genes during growth on root exudates.
- Taxon
- B. subtilis ATCC 6633
Bacillus subtilise0 - Treatment
- growth on root exudatese0
- Outcome
- expression of hundreds of genese0
- Direction
- regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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”
Claim · model-written summary
A. brasilense Sp245 regulated the expression of hundreds of genes during growth on root exudates.
- Taxon
- A. brasilense Sp245
Azospirillum brasilensee0 - Treatment
- growth on root exudatese0
- Outcome
- expression of hundreds of genese0
- Direction
- regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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”
Claim · model-written summary
P. fluorescens ATCC 17400 appeared to already express most of the genes required for the response to root exudates.
- Taxon
- P. fluorescens ATCC 17400
.JPG?width=60)
Pseudomonas fluorescense0 - Outcome
- express most of the genes required for this responsee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.JPG?width=500)
Verbatim
e0“P. fluorescens ATCC 17400 appeared to already express most of the genes required for this response”
Claim · model-written summary
Certain bacterial genes, mainly involved in metabolism, were regulated by all three root exudates through a core transcriptome.
- Taxon
- bacteriale0
- Treatment
- all three exudatese0
- Outcome
- certain bacterial genes, mainly involved in metabolisme0
- Direction
- regulatede0
Not reportedComparator
Verbatim
e0“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”
Claim · model-written summary
Other bacterial genes were specifically modulated by the exudates of each plant.
Not reportedComparator
Verbatim
e0“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”
Claim · model-written summary
Rapeseed root exudates stimulated amino acid metabolism in the PGPR.
Not reportedTaxonComparator
Verbatim
e0“rapeseed exudates stimulated amino acid metabolism”
Claim · model-written summary
Pea root exudates repressed motility of the PGPR.
Not reportedTaxonComparator
Verbatim
e0“pea exudates repressed motility”
Claim · model-written summary
Pea root exudates activated defense mechanisms in the PGPR.
Not reportedTaxonComparator
Verbatim
e0“pea exudates repressed motility and activated defense mechanisms”
Claim · model-written summary
Amino acids and sugars present in root exudates and metabolized by the PGPR were deduced.
- Outcome
- amino acids and sugars present in root exudates and metabolized by PGPRe0
Not reportedTaxon
Verbatim
e0“we deduced the amino acids and sugars present in root exudates and metabolized by PGPR”