Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates

Plant root secreted compounds alter the gene expression of associated microorganisms by acting as signal molecules that either stimulate or repel the interaction with beneficial or harmful species, respectively. However, it is still unclear whether two distinct groups of beneficial bacteria, non-pla...

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Main Authors: Yanglei Yi, Anne de Jong, Elrike Frenzel, Oscar P. Kuipers
Format: Article
Language:English
Published: Frontiers Media S.A. 2017-08-01
Series:Frontiers in Microbiology
Subjects:
Online Access:http://journal.frontiersin.org/article/10.3389/fmicb.2017.01487/full
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author Yanglei Yi
Anne de Jong
Elrike Frenzel
Oscar P. Kuipers
author_facet Yanglei Yi
Anne de Jong
Elrike Frenzel
Oscar P. Kuipers
author_sort Yanglei Yi
collection DOAJ
description Plant root secreted compounds alter the gene expression of associated microorganisms by acting as signal molecules that either stimulate or repel the interaction with beneficial or harmful species, respectively. However, it is still unclear whether two distinct groups of beneficial bacteria, non-plant-associated (soil) strains and plant-associated (endophytic) strains, respond uniformly or variably to the exposure with root exudates. Therefore, Bacillus mycoides, a potential biocontrol agent and plant growth-promoting bacterium, was isolated from the endosphere of potatoes and from soil of the same geographical region. Confocal fluorescence microscopy of plants inoculated with GFP-tagged B. mycoides strains showed that the endosphere isolate EC18 had a stronger plant colonization ability and competed more successfully for the colonization sites than the soil isolate SB8. To dissect these phenotypic differences, the genomes of the two strains were sequenced and the transcriptome response to potato root exudates was compared. The global transcriptome profiles evidenced that the endophytic isolate responded more pronounced than the soil-derived isolate and a higher number of significant differentially expressed genes were detected. Both isolates responded with the alteration of expression of an overlapping set of genes, which had previously been reported to be involved in plant–microbe interactions; including organic substance metabolism, oxidative reduction, and transmembrane transport. Notably, several genes were specifically upregulated in the endosphere isolate EC18, while being oppositely downregulated in the soil isolate SB8. These genes mainly encoded membrane proteins, transcriptional regulators or were involved in amino acid metabolism and biosynthesis. By contrast, several genes upregulated in the soil isolate SB8 and downregulated in the endosphere isolate EC18 were related to sugar transport, which might coincide with the different nutrient availability in the two environments. Altogether, the presented transcriptome profiles provide highly improved insights into the life strategies of plant-associated endophytes and soil isolates of B. mycoides.
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spelling doaj.art-c75b928606364c39bd460bf4497ce2c02022-12-21T18:15:54ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2017-08-01810.3389/fmicb.2017.01487283071Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil IsolatesYanglei YiAnne de JongElrike FrenzelOscar P. KuipersPlant root secreted compounds alter the gene expression of associated microorganisms by acting as signal molecules that either stimulate or repel the interaction with beneficial or harmful species, respectively. However, it is still unclear whether two distinct groups of beneficial bacteria, non-plant-associated (soil) strains and plant-associated (endophytic) strains, respond uniformly or variably to the exposure with root exudates. Therefore, Bacillus mycoides, a potential biocontrol agent and plant growth-promoting bacterium, was isolated from the endosphere of potatoes and from soil of the same geographical region. Confocal fluorescence microscopy of plants inoculated with GFP-tagged B. mycoides strains showed that the endosphere isolate EC18 had a stronger plant colonization ability and competed more successfully for the colonization sites than the soil isolate SB8. To dissect these phenotypic differences, the genomes of the two strains were sequenced and the transcriptome response to potato root exudates was compared. The global transcriptome profiles evidenced that the endophytic isolate responded more pronounced than the soil-derived isolate and a higher number of significant differentially expressed genes were detected. Both isolates responded with the alteration of expression of an overlapping set of genes, which had previously been reported to be involved in plant–microbe interactions; including organic substance metabolism, oxidative reduction, and transmembrane transport. Notably, several genes were specifically upregulated in the endosphere isolate EC18, while being oppositely downregulated in the soil isolate SB8. These genes mainly encoded membrane proteins, transcriptional regulators or were involved in amino acid metabolism and biosynthesis. By contrast, several genes upregulated in the soil isolate SB8 and downregulated in the endosphere isolate EC18 were related to sugar transport, which might coincide with the different nutrient availability in the two environments. Altogether, the presented transcriptome profiles provide highly improved insights into the life strategies of plant-associated endophytes and soil isolates of B. mycoides.http://journal.frontiersin.org/article/10.3389/fmicb.2017.01487/fullBacillus mycoidesendophyteroot colonizationtranscriptomeroot exudates
spellingShingle Yanglei Yi
Anne de Jong
Elrike Frenzel
Oscar P. Kuipers
Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates
Frontiers in Microbiology
Bacillus mycoides
endophyte
root colonization
transcriptome
root exudates
title Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates
title_full Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates
title_fullStr Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates
title_full_unstemmed Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates
title_short Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates
title_sort comparative transcriptomics of bacillus mycoides strains in response to potato root exudates reveals different genetic adaptation of endophytic and soil isolates
topic Bacillus mycoides
endophyte
root colonization
transcriptome
root exudates
url http://journal.frontiersin.org/article/10.3389/fmicb.2017.01487/full
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