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Diversity and Activity of Lysobacter Species from Disease Suppressive Soils.

Gómez Expósito R, Postma J, Raaijmakers JM, De Bruijn I - Front Microbiol (2015)

Bottom Line: In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds.However, their potential role in R. solani disease suppressive soil could not be confirmed.In-depth omics'-based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW) Wageningen, Netherlands ; Laboratory of Phytopathology, Wageningen University and Research Centre Wageningen, Netherlands.

ABSTRACT
The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani, but their actual role in disease suppression is still unclear. Here, the antifungal and plant growth-promoting activities of 18 Lysobacter strains, including 11 strains from Rhizoctonia-suppressive soils, were studied both in vitro and in vivo. Based on 16S rRNA sequencing, the Lysobacter strains from the Rhizoctonia-suppressive soil belonged to the four species Lysobacter antibioticus, Lysobacter capsici, Lysobacter enzymogenes, and Lysobacter gummosus. Most strains showed strong in vitro activity against R. solani and several other pathogens, including Pythium ultimum, Aspergillus niger, Fusarium oxysporum, and Xanthomonas campestris. When the Lysobacter strains were introduced into soil, however, no significant and consistent suppression of R. solani damping-off disease of sugar beet and cauliflower was observed. Subsequent bioassays further revealed that none of the Lysobacter strains was able to promote growth of sugar beet, cauliflower, onion, and Arabidopsis thaliana, either directly or via volatile compounds. The lack of in vivo activity is most likely attributed to poor colonization of the rhizosphere by the introduced Lysobacter strains. In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds. However, their potential role in R. solani disease suppressive soil could not be confirmed. In-depth omics'-based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils.

No MeSH data available.


Related in: MedlinePlus

Genetic diversity of 18 selected Lysobacter strains belonging to four different species. (A) Genetic profiling by BOX-PCR. Lanes on complete left and right shows Smartladder (Eurogentec) marker. (B) Phylogenetic tree of the Lysobacter strains based on the concatenated sequences of the 16S ribosomal RNA gene (16S rRNA), a gene encoding a recombination/repair protein (recN) and a gene encoding the subunit C of the excinuclease ABC (uvrC). The evolutionary relationship of the Lysobacter strains was inferred by alignment with ClustalW and neighbor-joining tree construction. The numbers at the nodes indicate the level of bootstrap support of 50 or higher, based on neighbor-joining analysis of 1000 resampled data sets. The bar indicates the relative number of substitutions per site.
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Figure 1: Genetic diversity of 18 selected Lysobacter strains belonging to four different species. (A) Genetic profiling by BOX-PCR. Lanes on complete left and right shows Smartladder (Eurogentec) marker. (B) Phylogenetic tree of the Lysobacter strains based on the concatenated sequences of the 16S ribosomal RNA gene (16S rRNA), a gene encoding a recombination/repair protein (recN) and a gene encoding the subunit C of the excinuclease ABC (uvrC). The evolutionary relationship of the Lysobacter strains was inferred by alignment with ClustalW and neighbor-joining tree construction. The numbers at the nodes indicate the level of bootstrap support of 50 or higher, based on neighbor-joining analysis of 1000 resampled data sets. The bar indicates the relative number of substitutions per site.

Mentions: BOX-PCR profiling of the 18 Lysobacter strains revealed a high genetic diversity among the different Lysobacter species and between strains of a given species (Figure 1A). L. gummosus strains showed the lowest intraspecific diversity whereas L. enzymogenes strains showed the highest diversity. Based on 16S rRNA sequences, the most phylogenetically distant species was L. enzymogenes (Figure S1A). When using either recN or uvrC or the three molecular markers together, however, L. antibioticus was the most distant of the four species (Figure 1B and Figures S1B,C).


Diversity and Activity of Lysobacter Species from Disease Suppressive Soils.

Gómez Expósito R, Postma J, Raaijmakers JM, De Bruijn I - Front Microbiol (2015)

Genetic diversity of 18 selected Lysobacter strains belonging to four different species. (A) Genetic profiling by BOX-PCR. Lanes on complete left and right shows Smartladder (Eurogentec) marker. (B) Phylogenetic tree of the Lysobacter strains based on the concatenated sequences of the 16S ribosomal RNA gene (16S rRNA), a gene encoding a recombination/repair protein (recN) and a gene encoding the subunit C of the excinuclease ABC (uvrC). The evolutionary relationship of the Lysobacter strains was inferred by alignment with ClustalW and neighbor-joining tree construction. The numbers at the nodes indicate the level of bootstrap support of 50 or higher, based on neighbor-joining analysis of 1000 resampled data sets. The bar indicates the relative number of substitutions per site.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644931&req=5

Figure 1: Genetic diversity of 18 selected Lysobacter strains belonging to four different species. (A) Genetic profiling by BOX-PCR. Lanes on complete left and right shows Smartladder (Eurogentec) marker. (B) Phylogenetic tree of the Lysobacter strains based on the concatenated sequences of the 16S ribosomal RNA gene (16S rRNA), a gene encoding a recombination/repair protein (recN) and a gene encoding the subunit C of the excinuclease ABC (uvrC). The evolutionary relationship of the Lysobacter strains was inferred by alignment with ClustalW and neighbor-joining tree construction. The numbers at the nodes indicate the level of bootstrap support of 50 or higher, based on neighbor-joining analysis of 1000 resampled data sets. The bar indicates the relative number of substitutions per site.
Mentions: BOX-PCR profiling of the 18 Lysobacter strains revealed a high genetic diversity among the different Lysobacter species and between strains of a given species (Figure 1A). L. gummosus strains showed the lowest intraspecific diversity whereas L. enzymogenes strains showed the highest diversity. Based on 16S rRNA sequences, the most phylogenetically distant species was L. enzymogenes (Figure S1A). When using either recN or uvrC or the three molecular markers together, however, L. antibioticus was the most distant of the four species (Figure 1B and Figures S1B,C).

Bottom Line: In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds.However, their potential role in R. solani disease suppressive soil could not be confirmed.In-depth omics'-based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW) Wageningen, Netherlands ; Laboratory of Phytopathology, Wageningen University and Research Centre Wageningen, Netherlands.

ABSTRACT
The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani, but their actual role in disease suppression is still unclear. Here, the antifungal and plant growth-promoting activities of 18 Lysobacter strains, including 11 strains from Rhizoctonia-suppressive soils, were studied both in vitro and in vivo. Based on 16S rRNA sequencing, the Lysobacter strains from the Rhizoctonia-suppressive soil belonged to the four species Lysobacter antibioticus, Lysobacter capsici, Lysobacter enzymogenes, and Lysobacter gummosus. Most strains showed strong in vitro activity against R. solani and several other pathogens, including Pythium ultimum, Aspergillus niger, Fusarium oxysporum, and Xanthomonas campestris. When the Lysobacter strains were introduced into soil, however, no significant and consistent suppression of R. solani damping-off disease of sugar beet and cauliflower was observed. Subsequent bioassays further revealed that none of the Lysobacter strains was able to promote growth of sugar beet, cauliflower, onion, and Arabidopsis thaliana, either directly or via volatile compounds. The lack of in vivo activity is most likely attributed to poor colonization of the rhizosphere by the introduced Lysobacter strains. In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds. However, their potential role in R. solani disease suppressive soil could not be confirmed. In-depth omics'-based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils.

No MeSH data available.


Related in: MedlinePlus