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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

In vivo Rhizoctonia disease suppression and rhizosphere colonization ability by Lysobacter strains. (A) Area under disease progress curve (AUDPC) of disease spread for sugar beet when Lysobacter strains were applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9); (B) Colonization of the rhizosphere of sugar beet by the Lysobacter strains when applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9). (C) AUDPC of disease spread for cauliflower when Lysobacter strains were applied into a conducive soil. 10^7 and 10^5 means an initial density of the inoculum at 107 and 105 cells/g soil, respectively; L. antibioticus: L02, L08, L23, L32, 173, 174; L. capsici: L12, L13, L14, L31; L. enzymogenes: L19, L28, L29, L30, and L. gummosus: L05, L15, L26, L33. For each of the two bioassays, an asterisk indicates a significant difference (p < 0.05) with the control treatment calculated by analysis of variance and Dunnet's post-hoc analysis.
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Figure 3: In vivo Rhizoctonia disease suppression and rhizosphere colonization ability by Lysobacter strains. (A) Area under disease progress curve (AUDPC) of disease spread for sugar beet when Lysobacter strains were applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9); (B) Colonization of the rhizosphere of sugar beet by the Lysobacter strains when applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9). (C) AUDPC of disease spread for cauliflower when Lysobacter strains were applied into a conducive soil. 10^7 and 10^5 means an initial density of the inoculum at 107 and 105 cells/g soil, respectively; L. antibioticus: L02, L08, L23, L32, 173, 174; L. capsici: L12, L13, L14, L31; L. enzymogenes: L19, L28, L29, L30, and L. gummosus: L05, L15, L26, L33. For each of the two bioassays, an asterisk indicates a significant difference (p < 0.05) with the control treatment calculated by analysis of variance and Dunnet's post-hoc analysis.

Mentions: The efficacy of the Lysobacter strains, several of which originate from Rhizoctonia suppressive soil, to control Rhizoctonia damping-off disease of sugar beet seedlings was tested in a sterilized (by autoclaving twice) sand-potting soil mixture and in a non-sterilized agricultural soil. Seed germination was not affected by the Lysobacter strains. In two bioassays, none of the strains was able to consistently suppress damping-off disease caused by R. solani after 2 weeks of plant growth (Figure 3A). For example, strains L19 and L05 significantly reduced damping-off disease of sugar beet in bioassay 2 but not in bioassay 1 (Figure 3A).


Diversity and Activity of Lysobacter Species from Disease Suppressive Soils.

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

In vivo Rhizoctonia disease suppression and rhizosphere colonization ability by Lysobacter strains. (A) Area under disease progress curve (AUDPC) of disease spread for sugar beet when Lysobacter strains were applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9); (B) Colonization of the rhizosphere of sugar beet by the Lysobacter strains when applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9). (C) AUDPC of disease spread for cauliflower when Lysobacter strains were applied into a conducive soil. 10^7 and 10^5 means an initial density of the inoculum at 107 and 105 cells/g soil, respectively; L. antibioticus: L02, L08, L23, L32, 173, 174; L. capsici: L12, L13, L14, L31; L. enzymogenes: L19, L28, L29, L30, and L. gummosus: L05, L15, L26, L33. For each of the two bioassays, an asterisk indicates a significant difference (p < 0.05) with the control treatment calculated by analysis of variance and Dunnet's post-hoc analysis.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 3: In vivo Rhizoctonia disease suppression and rhizosphere colonization ability by Lysobacter strains. (A) Area under disease progress curve (AUDPC) of disease spread for sugar beet when Lysobacter strains were applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9); (B) Colonization of the rhizosphere of sugar beet by the Lysobacter strains when applied at an initial density of 107 CFU/g into a mixture potting soil:sand (1:9). (C) AUDPC of disease spread for cauliflower when Lysobacter strains were applied into a conducive soil. 10^7 and 10^5 means an initial density of the inoculum at 107 and 105 cells/g soil, respectively; L. antibioticus: L02, L08, L23, L32, 173, 174; L. capsici: L12, L13, L14, L31; L. enzymogenes: L19, L28, L29, L30, and L. gummosus: L05, L15, L26, L33. For each of the two bioassays, an asterisk indicates a significant difference (p < 0.05) with the control treatment calculated by analysis of variance and Dunnet's post-hoc analysis.
Mentions: The efficacy of the Lysobacter strains, several of which originate from Rhizoctonia suppressive soil, to control Rhizoctonia damping-off disease of sugar beet seedlings was tested in a sterilized (by autoclaving twice) sand-potting soil mixture and in a non-sterilized agricultural soil. Seed germination was not affected by the Lysobacter strains. In two bioassays, none of the strains was able to consistently suppress damping-off disease caused by R. solani after 2 weeks of plant growth (Figure 3A). For example, strains L19 and L05 significantly reduced damping-off disease of sugar beet in bioassay 2 but not in bioassay 1 (Figure 3A).

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