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Induced systemic resistance against Botrytis cinerea by Micromonospora strains isolated from root nodules.

Martínez-Hidalgo P, García JM, Pozo MJ - Front Microbiol (2015)

Bottom Line: This induced systemic resistance, confirmed in different tomato cultivars, is long lasting.The defensive response of tomato plants inoculated with Micromonospora spp. differs from that of non-inoculated plants, showing a stronger induction of jasmonate-regulated defenses when the plant is challenged with a pathogen.The hypothesis of jasmonates playing a key role in this defense priming effect was confirmed using defense-impaired tomato mutants, since the JA-deficient line def1 was unable to display a long term induced resistance upon Micromonospora spp. inoculation.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Genetics, University of Salamanca Salamanca, Spain ; Unidad Asociada USAL-CSIC "Interacción Planta-Microorganismo" Salamanca, Spain.

ABSTRACT
Micromonospora is a Gram positive bacterium that can be isolated from nitrogen fixing nodules from healthy leguminous plants, where they could be beneficial to the plant. Their plant growth promoting activity in legume and non-legume plants has been previously demonstrated. The present study explores the ability of Micromonospora strains to control fungal pathogens and to stimulate plant immunity. Micromonospora strains isolated from surface sterilized nodules of alfalfa showed in vitro antifungal activity against several pathogenic fungi. Moreover, root inoculation of tomato plants with these Micromonospora strains effectively reduced leaf infection by the fungal pathogen Botrytis cinerea, despite spatial separation between both microorganisms. This induced systemic resistance, confirmed in different tomato cultivars, is long lasting. Gene expression analyses evidenced that Micromonospora stimulates the plant capacity to activate defense mechanisms upon pathogen attack. The defensive response of tomato plants inoculated with Micromonospora spp. differs from that of non-inoculated plants, showing a stronger induction of jasmonate-regulated defenses when the plant is challenged with a pathogen. The hypothesis of jasmonates playing a key role in this defense priming effect was confirmed using defense-impaired tomato mutants, since the JA-deficient line def1 was unable to display a long term induced resistance upon Micromonospora spp. inoculation. In conclusion, nodule isolated Micromonospora strains should be considered excellent candidates as biocontrol agents as they combine both direct antifungal activity against plant pathogens and the ability to prime plant immunity.

No MeSH data available.


Related in: MedlinePlus

Effect of Micromonospora ALFpr18c root inoculation on disease development caused by B. cinerea in different defense deficient tomato lines. (A) SA-deficient nahG and (B) JA-deficient def 1 plants. Necrosis severity caused by B. cinerea was scored using a three levels disease scale: mild, moderate and severe, as shown in Supplementary Figure S2. Control, plants not inoculated with Micromonospora; pr18c 1M and pr18c 1D, plants inoculated with Micromonospora sp. ALFpr18c 1 month or 1 day before challenge with B. cinerea, respectively. Within each genotype, bars not sharing a common letter (lowercase for mild, uppercase for moderate and greek for severe symptoms) are significantly different using Bonferroni corrected Chi-square tests, followed by z-tests (P ≤ 0.05).
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Figure 4: Effect of Micromonospora ALFpr18c root inoculation on disease development caused by B. cinerea in different defense deficient tomato lines. (A) SA-deficient nahG and (B) JA-deficient def 1 plants. Necrosis severity caused by B. cinerea was scored using a three levels disease scale: mild, moderate and severe, as shown in Supplementary Figure S2. Control, plants not inoculated with Micromonospora; pr18c 1M and pr18c 1D, plants inoculated with Micromonospora sp. ALFpr18c 1 month or 1 day before challenge with B. cinerea, respectively. Within each genotype, bars not sharing a common letter (lowercase for mild, uppercase for moderate and greek for severe symptoms) are significantly different using Bonferroni corrected Chi-square tests, followed by z-tests (P ≤ 0.05).

Mentions: The ability of Micromonospora sp. ALFpr18c to induce resistance against B. cinerea was analyzed in tomato plants impaired in JA or SA signaling (Figure 4). Tomato plants were challenged with B. cinerea 30 days after root inoculation with Micromonospora sp., as described in Section “Materials and Methods.”


Induced systemic resistance against Botrytis cinerea by Micromonospora strains isolated from root nodules.

Martínez-Hidalgo P, García JM, Pozo MJ - Front Microbiol (2015)

Effect of Micromonospora ALFpr18c root inoculation on disease development caused by B. cinerea in different defense deficient tomato lines. (A) SA-deficient nahG and (B) JA-deficient def 1 plants. Necrosis severity caused by B. cinerea was scored using a three levels disease scale: mild, moderate and severe, as shown in Supplementary Figure S2. Control, plants not inoculated with Micromonospora; pr18c 1M and pr18c 1D, plants inoculated with Micromonospora sp. ALFpr18c 1 month or 1 day before challenge with B. cinerea, respectively. Within each genotype, bars not sharing a common letter (lowercase for mild, uppercase for moderate and greek for severe symptoms) are significantly different using Bonferroni corrected Chi-square tests, followed by z-tests (P ≤ 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556977&req=5

Figure 4: Effect of Micromonospora ALFpr18c root inoculation on disease development caused by B. cinerea in different defense deficient tomato lines. (A) SA-deficient nahG and (B) JA-deficient def 1 plants. Necrosis severity caused by B. cinerea was scored using a three levels disease scale: mild, moderate and severe, as shown in Supplementary Figure S2. Control, plants not inoculated with Micromonospora; pr18c 1M and pr18c 1D, plants inoculated with Micromonospora sp. ALFpr18c 1 month or 1 day before challenge with B. cinerea, respectively. Within each genotype, bars not sharing a common letter (lowercase for mild, uppercase for moderate and greek for severe symptoms) are significantly different using Bonferroni corrected Chi-square tests, followed by z-tests (P ≤ 0.05).
Mentions: The ability of Micromonospora sp. ALFpr18c to induce resistance against B. cinerea was analyzed in tomato plants impaired in JA or SA signaling (Figure 4). Tomato plants were challenged with B. cinerea 30 days after root inoculation with Micromonospora sp., as described in Section “Materials and Methods.”

Bottom Line: This induced systemic resistance, confirmed in different tomato cultivars, is long lasting.The defensive response of tomato plants inoculated with Micromonospora spp. differs from that of non-inoculated plants, showing a stronger induction of jasmonate-regulated defenses when the plant is challenged with a pathogen.The hypothesis of jasmonates playing a key role in this defense priming effect was confirmed using defense-impaired tomato mutants, since the JA-deficient line def1 was unable to display a long term induced resistance upon Micromonospora spp. inoculation.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Genetics, University of Salamanca Salamanca, Spain ; Unidad Asociada USAL-CSIC "Interacción Planta-Microorganismo" Salamanca, Spain.

ABSTRACT
Micromonospora is a Gram positive bacterium that can be isolated from nitrogen fixing nodules from healthy leguminous plants, where they could be beneficial to the plant. Their plant growth promoting activity in legume and non-legume plants has been previously demonstrated. The present study explores the ability of Micromonospora strains to control fungal pathogens and to stimulate plant immunity. Micromonospora strains isolated from surface sterilized nodules of alfalfa showed in vitro antifungal activity against several pathogenic fungi. Moreover, root inoculation of tomato plants with these Micromonospora strains effectively reduced leaf infection by the fungal pathogen Botrytis cinerea, despite spatial separation between both microorganisms. This induced systemic resistance, confirmed in different tomato cultivars, is long lasting. Gene expression analyses evidenced that Micromonospora stimulates the plant capacity to activate defense mechanisms upon pathogen attack. The defensive response of tomato plants inoculated with Micromonospora spp. differs from that of non-inoculated plants, showing a stronger induction of jasmonate-regulated defenses when the plant is challenged with a pathogen. The hypothesis of jasmonates playing a key role in this defense priming effect was confirmed using defense-impaired tomato mutants, since the JA-deficient line def1 was unable to display a long term induced resistance upon Micromonospora spp. inoculation. In conclusion, nodule isolated Micromonospora strains should be considered excellent candidates as biocontrol agents as they combine both direct antifungal activity against plant pathogens and the ability to prime plant immunity.

No MeSH data available.


Related in: MedlinePlus