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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

Phenotypic characterization of the Lysobacter strains, including (A) motility, protease, chitinase and glucanase activities, and antagonistic activity against pathogenic fungi, oomycetes and bacteria. + indicates activity; − indicates no activity; ± indicates antagonistic activity observed after 2–3 days of incubation, but the activity disappeared upon longer incubation. For the enzymatic activity, the ± indicates weak activity; NT indicates not tested. (B) Pictures of phenotypic characterization of L. antibioticus (L. ant), L. capsici (L. cap), L. enzymogenes (L. enz), and L. gummosus (L. gum) for I: motility on SSM medium; II: chitinase activity; III: glucanase activity, positive glucanase activity is given by the change from red to orange color (not shown); IV: protease activity; and in vitro antagonistic activity on R2A (except when otherwise indicated) against V: R. solani; VI: Cercospora beticola; VII: Verticillium dahliae; VIII: Pythium ultimum; IX: Aphanomyces cochlioides on PDA and X: Xanthomonas campestris pv. campestris on 1/5th PDA.
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Figure 2: Phenotypic characterization of the Lysobacter strains, including (A) motility, protease, chitinase and glucanase activities, and antagonistic activity against pathogenic fungi, oomycetes and bacteria. + indicates activity; − indicates no activity; ± indicates antagonistic activity observed after 2–3 days of incubation, but the activity disappeared upon longer incubation. For the enzymatic activity, the ± indicates weak activity; NT indicates not tested. (B) Pictures of phenotypic characterization of L. antibioticus (L. ant), L. capsici (L. cap), L. enzymogenes (L. enz), and L. gummosus (L. gum) for I: motility on SSM medium; II: chitinase activity; III: glucanase activity, positive glucanase activity is given by the change from red to orange color (not shown); IV: protease activity; and in vitro antagonistic activity on R2A (except when otherwise indicated) against V: R. solani; VI: Cercospora beticola; VII: Verticillium dahliae; VIII: Pythium ultimum; IX: Aphanomyces cochlioides on PDA and X: Xanthomonas campestris pv. campestris on 1/5th PDA.

Mentions: The Lysobacter strains did not show any motility after 4 days of incubation on soft SSM agar medium. After 12 days of incubation, however, L. capsici (L12, L13, L14, and L31) and L. enzymogenes (L19, L28, L29, L30) did spread from the point of inoculation, most likely due to gliding motility (Figure 2). All Lysobacter strains used in this study showed extracellular chitinase and glucanase activities (Figure 2). Most strains presented proteolytic activity except for two L. gummosus and four L. antibioticus strains (Figure 2). Variation in these three enzymatic activities among strains belonging to the same species was observed, especially for the L. antibioticus strains.


Diversity and Activity of Lysobacter Species from Disease Suppressive Soils.

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

Phenotypic characterization of the Lysobacter strains, including (A) motility, protease, chitinase and glucanase activities, and antagonistic activity against pathogenic fungi, oomycetes and bacteria. + indicates activity; − indicates no activity; ± indicates antagonistic activity observed after 2–3 days of incubation, but the activity disappeared upon longer incubation. For the enzymatic activity, the ± indicates weak activity; NT indicates not tested. (B) Pictures of phenotypic characterization of L. antibioticus (L. ant), L. capsici (L. cap), L. enzymogenes (L. enz), and L. gummosus (L. gum) for I: motility on SSM medium; II: chitinase activity; III: glucanase activity, positive glucanase activity is given by the change from red to orange color (not shown); IV: protease activity; and in vitro antagonistic activity on R2A (except when otherwise indicated) against V: R. solani; VI: Cercospora beticola; VII: Verticillium dahliae; VIII: Pythium ultimum; IX: Aphanomyces cochlioides on PDA and X: Xanthomonas campestris pv. campestris on 1/5th PDA.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 2: Phenotypic characterization of the Lysobacter strains, including (A) motility, protease, chitinase and glucanase activities, and antagonistic activity against pathogenic fungi, oomycetes and bacteria. + indicates activity; − indicates no activity; ± indicates antagonistic activity observed after 2–3 days of incubation, but the activity disappeared upon longer incubation. For the enzymatic activity, the ± indicates weak activity; NT indicates not tested. (B) Pictures of phenotypic characterization of L. antibioticus (L. ant), L. capsici (L. cap), L. enzymogenes (L. enz), and L. gummosus (L. gum) for I: motility on SSM medium; II: chitinase activity; III: glucanase activity, positive glucanase activity is given by the change from red to orange color (not shown); IV: protease activity; and in vitro antagonistic activity on R2A (except when otherwise indicated) against V: R. solani; VI: Cercospora beticola; VII: Verticillium dahliae; VIII: Pythium ultimum; IX: Aphanomyces cochlioides on PDA and X: Xanthomonas campestris pv. campestris on 1/5th PDA.
Mentions: The Lysobacter strains did not show any motility after 4 days of incubation on soft SSM agar medium. After 12 days of incubation, however, L. capsici (L12, L13, L14, and L31) and L. enzymogenes (L19, L28, L29, L30) did spread from the point of inoculation, most likely due to gliding motility (Figure 2). All Lysobacter strains used in this study showed extracellular chitinase and glucanase activities (Figure 2). Most strains presented proteolytic activity except for two L. gummosus and four L. antibioticus strains (Figure 2). Variation in these three enzymatic activities among strains belonging to the same species was observed, especially for the L. antibioticus strains.

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