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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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Expression levels of seven target genes of 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 four replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 18; P<0.05). Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 9; P<0.05).
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pone-0019751-g001: Expression levels of seven target genes of 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 four replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 18; P<0.05). Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 9; P<0.05).

Mentions: Elevated CO2 increased PAL, GST, PR1, and BGL2 levels of uninfected spr2 plants (Figure 1, Table S1). In contrast, elevated CO2 reduced the PAL level only of uninfected 35S plants (F1,6 = 9.16, P = 0.023). Regardless of CO2 level, uninfected 35S plants had the highest PI1 and PR1 levels among the genotypes. Furthermore, regardless of CO2 level, the 14-dpi treatment (nematodes added 14 days before sampling) increased PAL, PR1, and BGL2 levels and reduced the PI1 and RUBISCO level of spr2 plants, and increased the PI1, PAL, GST, PR1, and BGL2 levels of 35S plants. The 14-dpi treatment increased the PI1 and PAL levels of Wt plants under ambient CO2 and the GST, PR1, and BGL2 levels under elevated CO2. Elevated CO2 reduced the PI1 and LOX levels of Wt plants but increased the GST, PR1, and BGL2 levels of spr2 and Wt plants at 14-dpi. Elevated CO2 decreased the PI1 and PAL levels of 35S plants at 7- and 14-dpi (Figure 1).


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)

Expression levels of seven target genes of 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 four replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 18; P<0.05). Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 9; P<0.05).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0019751-g001: Expression levels of seven target genes of 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 four replicates. Different lowercase letters indicate significant differences among combinations of nematode and CO2 level within the same tomato genotype (LSD test: d.f. = 5, 18; P<0.05). Different uppercase letters indicate significant differences among tomato genotypes within the same CO2 and nematode treatment (LSD test: d.f. = 2, 9; P<0.05).
Mentions: Elevated CO2 increased PAL, GST, PR1, and BGL2 levels of uninfected spr2 plants (Figure 1, Table S1). In contrast, elevated CO2 reduced the PAL level only of uninfected 35S plants (F1,6 = 9.16, P = 0.023). Regardless of CO2 level, uninfected 35S plants had the highest PI1 and PR1 levels among the genotypes. Furthermore, regardless of CO2 level, the 14-dpi treatment (nematodes added 14 days before sampling) increased PAL, PR1, and BGL2 levels and reduced the PI1 and RUBISCO level of spr2 plants, and increased the PI1, PAL, GST, PR1, and BGL2 levels of 35S plants. The 14-dpi treatment increased the PI1 and PAL levels of Wt plants under ambient CO2 and the GST, PR1, and BGL2 levels under elevated CO2. Elevated CO2 reduced the PI1 and LOX levels of Wt plants but increased the GST, PR1, and BGL2 levels of spr2 and Wt plants at 14-dpi. Elevated CO2 decreased the PI1 and PAL levels of 35S plants at 7- and 14-dpi (Figure 1).

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