Limits...
Biocontrol agents promote growth of potato pathogens, depending on environmental conditions.

Cray JA, Connor MC, Stevenson A, Houghton JD, Rangel DE, Cooke LR, Hallsworth JE - Microb Biotechnol (2016)

Bottom Line: Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells.Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field-relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields.These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode-of-behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.

View Article: PubMed Central - PubMed

Affiliation: Institute for Global Food Security, School of Biological Sciences, MBC, Queen's University Belfast, Belfast, BT9 7BL, Northern Ireland.

No MeSH data available.


Related in: MedlinePlus

Interactions between Fusarium coeruleum and biocontrol agents on (A–C) NA+1.583 M glycerol and (D–F) NA+1.104 M NaCl: (A and D) radial extension of F. coeruleum on the side adjacent to the biocontrol agent (dotted lines indicate the distance between F. coeruleum and biocontrol agent at the time of inoculation); (B and E) extent of colony of biocontrol agent beyond the initial zone‐of‐inoculation (over time), on the side adjacent to F. coeruleum; and (C and F) distance between F. coeruleum and potential biocontrol agent over time. Upon inoculation on NA+1.583 M glycerol and NA+1.104 M NaCl, F. coeruleum and the biocontrol agents were placed 12‐ and 7‐mm apart, respectively. Error bars indicate ± standard error.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4835571&req=5

mbt212349-fig-0005: Interactions between Fusarium coeruleum and biocontrol agents on (A–C) NA+1.583 M glycerol and (D–F) NA+1.104 M NaCl: (A and D) radial extension of F. coeruleum on the side adjacent to the biocontrol agent (dotted lines indicate the distance between F. coeruleum and biocontrol agent at the time of inoculation); (B and E) extent of colony of biocontrol agent beyond the initial zone‐of‐inoculation (over time), on the side adjacent to F. coeruleum; and (C and F) distance between F. coeruleum and potential biocontrol agent over time. Upon inoculation on NA+1.583 M glycerol and NA+1.104 M NaCl, F. coeruleum and the biocontrol agents were placed 12‐ and 7‐mm apart, respectively. Error bars indicate ± standard error.

Mentions: Of the strains isolated, others with potent biocontrol activity included JC12GB14, followed by JC12GB6, JC12GB7 and then JC12GB13, all of which were originally isolated on NA+glycerol (0.957 water activity; Figs 4 and 5; Fig. S4; Tables S1, S3 and S4). Overall, the inhibition‐coefficient values for isolates able to reduce growth of plant pathogens during the interaction assays ranged from 2.92 to 84.2, 2.64 to 77.7, 21.6 to 83.0 and 0.85 to 87.0 for F. coeruleum, F. sambucinum, P. infestans strain 10D2_5 and P. infestans strain 10LD3 respectively (Figs 2, 3, 4; Tables S1–S4). In addition, several of the potential biocontrol agents (JC12GB28, JC12GB35, JC12GB54), all of which were obtained from leaf surfaces (Table 1), actually promoted growth of the plant pathogens (and so exhibited negative values for inhibition coefficients) (Figs 1D–F, 2A, 3A and 4; Figs S2A–C and S4; Tables S1–S4). For instance, strain JC12GB54, which was not motile (see Fig. 1E) enhanced growth rate of F. coeruleum by 0.61 mm day−1 (Figs 1D and 2A). By contrast, strains JC12GB64, JC12GB65 and JC12GB75 were relatively ineffective as they were neither inhibitory nor able to promote growth of plant pathogens, regardless of species (Figs 1D–F, 2A, 3A; Fig. S2; Tables S1 and S2). Promotion of F. coeruleum was pronounced; growth rates were 202% that of the PDA+132 mM urea control (no biocontrol agent), when cultured on PDA+132 mM urea in the presence of Bacillus sp. JC12GB43 and 123% that of the PDA control (no biocontrol agent) on PDA in the presence of strain JC12GB54 (Fig. 2A and C; Tables S1 and S5). Growth rate of P. infestans 10D2_5 was 139% that of the CA control (no biocontrol agent) when cultured on CA and in the presence of strain JC12GB28 (Fig. 4A; Table S4). This acts as proof‐of‐principle that a potent biocontrol agents can promote proliferation of the pathogen.


Biocontrol agents promote growth of potato pathogens, depending on environmental conditions.

Cray JA, Connor MC, Stevenson A, Houghton JD, Rangel DE, Cooke LR, Hallsworth JE - Microb Biotechnol (2016)

Interactions between Fusarium coeruleum and biocontrol agents on (A–C) NA+1.583 M glycerol and (D–F) NA+1.104 M NaCl: (A and D) radial extension of F. coeruleum on the side adjacent to the biocontrol agent (dotted lines indicate the distance between F. coeruleum and biocontrol agent at the time of inoculation); (B and E) extent of colony of biocontrol agent beyond the initial zone‐of‐inoculation (over time), on the side adjacent to F. coeruleum; and (C and F) distance between F. coeruleum and potential biocontrol agent over time. Upon inoculation on NA+1.583 M glycerol and NA+1.104 M NaCl, F. coeruleum and the biocontrol agents were placed 12‐ and 7‐mm apart, respectively. Error bars indicate ± standard error.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835571&req=5

mbt212349-fig-0005: Interactions between Fusarium coeruleum and biocontrol agents on (A–C) NA+1.583 M glycerol and (D–F) NA+1.104 M NaCl: (A and D) radial extension of F. coeruleum on the side adjacent to the biocontrol agent (dotted lines indicate the distance between F. coeruleum and biocontrol agent at the time of inoculation); (B and E) extent of colony of biocontrol agent beyond the initial zone‐of‐inoculation (over time), on the side adjacent to F. coeruleum; and (C and F) distance between F. coeruleum and potential biocontrol agent over time. Upon inoculation on NA+1.583 M glycerol and NA+1.104 M NaCl, F. coeruleum and the biocontrol agents were placed 12‐ and 7‐mm apart, respectively. Error bars indicate ± standard error.
Mentions: Of the strains isolated, others with potent biocontrol activity included JC12GB14, followed by JC12GB6, JC12GB7 and then JC12GB13, all of which were originally isolated on NA+glycerol (0.957 water activity; Figs 4 and 5; Fig. S4; Tables S1, S3 and S4). Overall, the inhibition‐coefficient values for isolates able to reduce growth of plant pathogens during the interaction assays ranged from 2.92 to 84.2, 2.64 to 77.7, 21.6 to 83.0 and 0.85 to 87.0 for F. coeruleum, F. sambucinum, P. infestans strain 10D2_5 and P. infestans strain 10LD3 respectively (Figs 2, 3, 4; Tables S1–S4). In addition, several of the potential biocontrol agents (JC12GB28, JC12GB35, JC12GB54), all of which were obtained from leaf surfaces (Table 1), actually promoted growth of the plant pathogens (and so exhibited negative values for inhibition coefficients) (Figs 1D–F, 2A, 3A and 4; Figs S2A–C and S4; Tables S1–S4). For instance, strain JC12GB54, which was not motile (see Fig. 1E) enhanced growth rate of F. coeruleum by 0.61 mm day−1 (Figs 1D and 2A). By contrast, strains JC12GB64, JC12GB65 and JC12GB75 were relatively ineffective as they were neither inhibitory nor able to promote growth of plant pathogens, regardless of species (Figs 1D–F, 2A, 3A; Fig. S2; Tables S1 and S2). Promotion of F. coeruleum was pronounced; growth rates were 202% that of the PDA+132 mM urea control (no biocontrol agent), when cultured on PDA+132 mM urea in the presence of Bacillus sp. JC12GB43 and 123% that of the PDA control (no biocontrol agent) on PDA in the presence of strain JC12GB54 (Fig. 2A and C; Tables S1 and S5). Growth rate of P. infestans 10D2_5 was 139% that of the CA control (no biocontrol agent) when cultured on CA and in the presence of strain JC12GB28 (Fig. 4A; Table S4). This acts as proof‐of‐principle that a potent biocontrol agents can promote proliferation of the pathogen.

Bottom Line: Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells.Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field-relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields.These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode-of-behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.

View Article: PubMed Central - PubMed

Affiliation: Institute for Global Food Security, School of Biological Sciences, MBC, Queen's University Belfast, Belfast, BT9 7BL, Northern Ireland.

No MeSH data available.


Related in: MedlinePlus