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Elevated CO2 influences nematode-induced defense responses of tomato genotypes differing in the JA pathway.

Sun Y, Yin J, Cao H, Li C, Kang L, Ge F - PLoS ONE (2011)

Bottom Line: In the current study, we tested the hypothesis that elevated CO(2) will favor the salicylic acid (SA)-pathway defense but repress the jasmonic acid (JA)-pathway defense of plants against plant-parasitic nematodes.Our results suggest that, in terms of defense genes, secondary metabolites, and volatile organic compounds, induced defense of nematode-infected plants could be affected by elevated CO(2), and that CO(2)-induced changes of plant resistance may lead to genotype-specific responses of plants to nematodes under elevated CO(2).The changes in resistance against nematodes, however, were small relative to those reported for chewing insects.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Integrated Management of Pest and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China.

ABSTRACT
Rising atmospheric CO(2) concentrations can affect the induced defense of plants against chewing herbivores but little is known about whether elevated CO(2) can change the induced defense of plants against parasitic nematodes. This study examined the interactions between the root-knot nematode Meloidogyne incognita and three isogenic tomato (Lycopersicon esculentum) genotypes grown under ambient (390 ppm) and elevated (750 ppm) CO(2) in growth chambers. In a previous study with open-top chambers in the field, we reported that elevated CO(2) increased the number of nematode-induced root galls in a JA-defense-dominated genotype but not in a wild-type or JA-defense-recessive genotype. In the current study, we tested the hypothesis that elevated CO(2) will favor the salicylic acid (SA)-pathway defense but repress the jasmonic acid (JA)-pathway defense of plants against plant-parasitic nematodes. Our data showed that elevated CO(2) reduced the JA-pathway defense against M. incognita in the wild-type and in a genotype in which defense is dominated by the JA pathway (a JA-defense-dominated genotype) but up-regulated the SA-pathway defense in the wild type and in a JA-defense-recessive genotype (jasmonate-deficient mutant). Our results suggest that, in terms of defense genes, secondary metabolites, and volatile organic compounds, induced defense of nematode-infected plants could be affected by elevated CO(2), and that CO(2)-induced changes of plant resistance may lead to genotype-specific responses of plants to nematodes under elevated CO(2). The changes in resistance against nematodes, however, were small relative to those reported for chewing insects.

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Emission rate of total volatile organic compounds (VOC) from tomato genotypes grown under ambient and elevated CO2 without (“-”) and with M. incognita; plants with M. incognita were sampled 7 days post-inoculation (7 dpi) and 14 dpi.Each value represents the average (±SE) of three replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 12; P<0.05); Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 6; P<0.05). Emission rate represents ng of compound released by 10 g (fresh weight) of leaves per hour.
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pone-0019751-g003: Emission rate of total volatile organic compounds (VOC) from tomato genotypes grown under ambient and elevated CO2 without (“-”) and with M. incognita; plants with M. incognita were sampled 7 days post-inoculation (7 dpi) and 14 dpi.Each value represents the average (±SE) of three replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 12; P<0.05); Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 6; P<0.05). Emission rate represents ng of compound released by 10 g (fresh weight) of leaves per hour.

Mentions: CO2 level, tomato genotype, nematode infection, and the interaction between CO2 and nematode significantly affected the total amount of VOC (Table S3). In the absence of nematodes, elevated CO2 reduced the total amount of VOC released by spr2 plants. The jasmonate-deficient spr2 and Wt plants released less VOC than 35S plants under both ambient and elevated CO2 (Figure 3). Elevated CO2 reduced emission of ocimene and β-phellandrene in uninfected spr2 plants and hexenal in uninfected 35S plants. In the 14-dpi treatment under elevated CO2, spr2 plants emitted less of each volatile terpene than 35S plants (Table S4).


Elevated CO2 influences nematode-induced defense responses of tomato genotypes differing in the JA pathway.

Sun Y, Yin J, Cao H, Li C, Kang L, Ge F - PLoS ONE (2011)

Emission rate of total volatile organic compounds (VOC) from tomato genotypes grown under ambient and elevated CO2 without (“-”) and with M. incognita; plants with M. incognita were sampled 7 days post-inoculation (7 dpi) and 14 dpi.Each value represents the average (±SE) of three replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 12; P<0.05); Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 6; P<0.05). Emission rate represents ng of compound released by 10 g (fresh weight) of leaves per hour.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3101209&req=5

pone-0019751-g003: Emission rate of total volatile organic compounds (VOC) from tomato genotypes grown under ambient and elevated CO2 without (“-”) and with M. incognita; plants with M. incognita were sampled 7 days post-inoculation (7 dpi) and 14 dpi.Each value represents the average (±SE) of three replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 12; P<0.05); Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 6; P<0.05). Emission rate represents ng of compound released by 10 g (fresh weight) of leaves per hour.
Mentions: CO2 level, tomato genotype, nematode infection, and the interaction between CO2 and nematode significantly affected the total amount of VOC (Table S3). In the absence of nematodes, elevated CO2 reduced the total amount of VOC released by spr2 plants. The jasmonate-deficient spr2 and Wt plants released less VOC than 35S plants under both ambient and elevated CO2 (Figure 3). Elevated CO2 reduced emission of ocimene and β-phellandrene in uninfected spr2 plants and hexenal in uninfected 35S plants. In the 14-dpi treatment under elevated CO2, spr2 plants emitted less of each volatile terpene than 35S plants (Table S4).

Bottom Line: In the current study, we tested the hypothesis that elevated CO(2) will favor the salicylic acid (SA)-pathway defense but repress the jasmonic acid (JA)-pathway defense of plants against plant-parasitic nematodes.Our results suggest that, in terms of defense genes, secondary metabolites, and volatile organic compounds, induced defense of nematode-infected plants could be affected by elevated CO(2), and that CO(2)-induced changes of plant resistance may lead to genotype-specific responses of plants to nematodes under elevated CO(2).The changes in resistance against nematodes, however, were small relative to those reported for chewing insects.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Integrated Management of Pest and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China.

ABSTRACT
Rising atmospheric CO(2) concentrations can affect the induced defense of plants against chewing herbivores but little is known about whether elevated CO(2) can change the induced defense of plants against parasitic nematodes. This study examined the interactions between the root-knot nematode Meloidogyne incognita and three isogenic tomato (Lycopersicon esculentum) genotypes grown under ambient (390 ppm) and elevated (750 ppm) CO(2) in growth chambers. In a previous study with open-top chambers in the field, we reported that elevated CO(2) increased the number of nematode-induced root galls in a JA-defense-dominated genotype but not in a wild-type or JA-defense-recessive genotype. In the current study, we tested the hypothesis that elevated CO(2) will favor the salicylic acid (SA)-pathway defense but repress the jasmonic acid (JA)-pathway defense of plants against plant-parasitic nematodes. Our data showed that elevated CO(2) reduced the JA-pathway defense against M. incognita in the wild-type and in a genotype in which defense is dominated by the JA pathway (a JA-defense-dominated genotype) but up-regulated the SA-pathway defense in the wild type and in a JA-defense-recessive genotype (jasmonate-deficient mutant). Our results suggest that, in terms of defense genes, secondary metabolites, and volatile organic compounds, induced defense of nematode-infected plants could be affected by elevated CO(2), and that CO(2)-induced changes of plant resistance may lead to genotype-specific responses of plants to nematodes under elevated CO(2). The changes in resistance against nematodes, however, were small relative to those reported for chewing insects.

Show MeSH