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Catalases Induction in High Virulence Pinewood Nematode Bursaphelenchus xylophilus under Hydrogen Peroxide-Induced Stress.

Vicente CS, Ikuyo Y, Shinya R, Mota M, Hasegawa K - PLoS ONE (2015)

Bottom Line: Only successful, virulent nematodes are able to tolerate the basal plant defences, and furthermore migrate and proliferate inside of the host tree.Both catalases are expressed throughout the nematode intestine.Our results suggest that catalases of high virulence B. xylophilus were crucial for nematode survival under prolonged exposure to in vitro oxidative stress, highlighting their adaptive response, which could contribute to their success in host conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Biology, College of Bioscience & Biotechnology, Chubu University, Kasugai, Aichi, Japan; ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Departamento de Biologia, Universidade de Évora, Évora, Portugal.

ABSTRACT
Considered an EPPO A2 quarantine pest, Bursaphelenchus xylophilus is the causal agent of the pine wilt disease and the most devastating plant parasitic nematode attacking coniferous trees in the world. In the early stages of invasion, this nematode has to manage host defence mechanisms, such as strong oxidative stress. Only successful, virulent nematodes are able to tolerate the basal plant defences, and furthermore migrate and proliferate inside of the host tree. In this work, our main objective was to understand to what extent B. xylophilus catalases are involved in their tolerance to oxidative stress and virulence, using as oxidant agent the reactive oxygen species hydrogen peroxide (H2O2). After 24 hours of exposure, high virulence isolates of B. xylophilus could withstand higher H2O2 concentrations in comparison with low virulence B. xylophilus and B. mucronatus, corroborating our observation of Bxy-ctl-1 and Bxy-ctl-2 catalase up-regulation under the same experimental conditions. Both catalases are expressed throughout the nematode intestine. In addition, transgenic strains of Caenorhabditis elegans overexpressing B. xylophilus catalases were constructed and evaluated for survival under similar conditions as previously. Our results suggest that catalases of high virulence B. xylophilus were crucial for nematode survival under prolonged exposure to in vitro oxidative stress, highlighting their adaptive response, which could contribute to their success in host conditions.

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Related in: MedlinePlus

Survival percentage of Bursaphelenchus sp. isolates (high virulence B. xylophilus Ka4 and B. xylophilus T4, and low virulence B. xylophilus C14-5 and B. mucronatus Un1) after 24 hours exposition to H2O2 conditions (H2O2 concentrations ranging from 0 to 40 mM).Error bars represent standard deviation. Different letters above the columns indicate significant differences (p < 0.05) between Bursaphelenchus sp. isolates survival percentages in each H2O2 treatment, according to post-hoc Duncan’s test.
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pone.0123839.g001: Survival percentage of Bursaphelenchus sp. isolates (high virulence B. xylophilus Ka4 and B. xylophilus T4, and low virulence B. xylophilus C14-5 and B. mucronatus Un1) after 24 hours exposition to H2O2 conditions (H2O2 concentrations ranging from 0 to 40 mM).Error bars represent standard deviation. Different letters above the columns indicate significant differences (p < 0.05) between Bursaphelenchus sp. isolates survival percentages in each H2O2 treatment, according to post-hoc Duncan’s test.

Mentions: B. xylophilus (high virulence: Bx Ka4 and Bx T4; low virulence: Bx C14-5) and B. mucronatus (low virulence: Bm Un1) isolates were tested in increasing concentrations of H2O2 (0, 15, 20, 30 and 40 mM). After a 24h-exposure to this oxidant, nematode survival was examined (Fig 1). A clear difference between high and low virulence isolates was observed, even in the lowest H2O2 concentration (15 mM). The isolate Bx Ka4 seemed to be the most tolerant to H2O2 at all concentrations followed by Bx T4. Statistical differences (p < 0.05) between Bx Ka4 and Bx T4 were found in all H2O2 concentrations. Low virulence isolates (Bm Un1 and Bx C14-5) were sensitive to H2O2, having low survival even in 15 mM H2O2. No statistical differences (p > 0.05) were found between isolates.


Catalases Induction in High Virulence Pinewood Nematode Bursaphelenchus xylophilus under Hydrogen Peroxide-Induced Stress.

Vicente CS, Ikuyo Y, Shinya R, Mota M, Hasegawa K - PLoS ONE (2015)

Survival percentage of Bursaphelenchus sp. isolates (high virulence B. xylophilus Ka4 and B. xylophilus T4, and low virulence B. xylophilus C14-5 and B. mucronatus Un1) after 24 hours exposition to H2O2 conditions (H2O2 concentrations ranging from 0 to 40 mM).Error bars represent standard deviation. Different letters above the columns indicate significant differences (p < 0.05) between Bursaphelenchus sp. isolates survival percentages in each H2O2 treatment, according to post-hoc Duncan’s test.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4404050&req=5

pone.0123839.g001: Survival percentage of Bursaphelenchus sp. isolates (high virulence B. xylophilus Ka4 and B. xylophilus T4, and low virulence B. xylophilus C14-5 and B. mucronatus Un1) after 24 hours exposition to H2O2 conditions (H2O2 concentrations ranging from 0 to 40 mM).Error bars represent standard deviation. Different letters above the columns indicate significant differences (p < 0.05) between Bursaphelenchus sp. isolates survival percentages in each H2O2 treatment, according to post-hoc Duncan’s test.
Mentions: B. xylophilus (high virulence: Bx Ka4 and Bx T4; low virulence: Bx C14-5) and B. mucronatus (low virulence: Bm Un1) isolates were tested in increasing concentrations of H2O2 (0, 15, 20, 30 and 40 mM). After a 24h-exposure to this oxidant, nematode survival was examined (Fig 1). A clear difference between high and low virulence isolates was observed, even in the lowest H2O2 concentration (15 mM). The isolate Bx Ka4 seemed to be the most tolerant to H2O2 at all concentrations followed by Bx T4. Statistical differences (p < 0.05) between Bx Ka4 and Bx T4 were found in all H2O2 concentrations. Low virulence isolates (Bm Un1 and Bx C14-5) were sensitive to H2O2, having low survival even in 15 mM H2O2. No statistical differences (p > 0.05) were found between isolates.

Bottom Line: Only successful, virulent nematodes are able to tolerate the basal plant defences, and furthermore migrate and proliferate inside of the host tree.Both catalases are expressed throughout the nematode intestine.Our results suggest that catalases of high virulence B. xylophilus were crucial for nematode survival under prolonged exposure to in vitro oxidative stress, highlighting their adaptive response, which could contribute to their success in host conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Biology, College of Bioscience & Biotechnology, Chubu University, Kasugai, Aichi, Japan; ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Departamento de Biologia, Universidade de Évora, Évora, Portugal.

ABSTRACT
Considered an EPPO A2 quarantine pest, Bursaphelenchus xylophilus is the causal agent of the pine wilt disease and the most devastating plant parasitic nematode attacking coniferous trees in the world. In the early stages of invasion, this nematode has to manage host defence mechanisms, such as strong oxidative stress. Only successful, virulent nematodes are able to tolerate the basal plant defences, and furthermore migrate and proliferate inside of the host tree. In this work, our main objective was to understand to what extent B. xylophilus catalases are involved in their tolerance to oxidative stress and virulence, using as oxidant agent the reactive oxygen species hydrogen peroxide (H2O2). After 24 hours of exposure, high virulence isolates of B. xylophilus could withstand higher H2O2 concentrations in comparison with low virulence B. xylophilus and B. mucronatus, corroborating our observation of Bxy-ctl-1 and Bxy-ctl-2 catalase up-regulation under the same experimental conditions. Both catalases are expressed throughout the nematode intestine. In addition, transgenic strains of Caenorhabditis elegans overexpressing B. xylophilus catalases were constructed and evaluated for survival under similar conditions as previously. Our results suggest that catalases of high virulence B. xylophilus were crucial for nematode survival under prolonged exposure to in vitro oxidative stress, highlighting their adaptive response, which could contribute to their success in host conditions.

Show MeSH
Related in: MedlinePlus