Elevated CO2 changes the interactions between nematode and tomato genotypes differing in the JA pathway.
Interactions between the root-knot nematode Meloidogyne incognita and three isogenic tomato (Lycopersicon esculentum) genotypes were examined when plants were grown under ambient (370 ppm) and elevated (750 ppm) CO2. We tested the hypothesis that, defence-recessive genotypes tend to allocate 'extra' carbon (relative to nitrogen) to growth under elevated CO2, whereas defence-dominated genotypes allocate extra carbon to defence, and thereby increases the defence against nematodes. For all three genotypes, elevated CO2 increased height, biomass, and root and leaf total non-structural carbohydrates (TNC):N ratio, and decreased amino acids and proteins in leaves. The activity of anti-oxidant enzymes (superoxide dismutase and catalase) was enhanced by nematode infection in defence-recessive genotypes. Furthermore, elevated CO2 and nematode infection did not qualitatively change the volatile organic compounds (VOC) emitted from plants. Elevated CO2 increased the VOC emission rate only for defence-dominated genotypes that were not infected with nematodes. Elevated CO2 increased the number of nematode-induced galls on defence-dominated genotypes but not on wild-types or defence-recessive genotypes roots. Our results suggest that CO2 enrichment may not only increase plant C : N ratio but can disrupt the allocation of plant resources between growth and defence in some genetically modified plants and thereby reduce their resistance to nematodes.
State Key Laboratory of Integrated Management of Pest and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Yucheng
Y
Sun
Haifeng
H
Cao
Jin
J
Yin
L E
LE
Kang
Feng
F
Ge
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D018533:Biomass; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D003517:Cyclopentanes; D005838:Genotype; D006790:Host-Parasite Interactions; D018551:Solanum lycopersicum / Q000235:genetics* / Q000469:parasitology*; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism; D054883:Oxylipins; D018515:Plant Leaves / Q000254:growth & development; D018517:Plant Roots / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000235:genetics / Q000469:parasitology; D014431:Tylenchoidea / Q000502:physiology*; D055549:Volatile Organic Compounds / Q000378:metabolism
D000975:Antioxidants; D003517:Cyclopentanes; D054883:Oxylipins; D055549:Volatile Organic Compounds; D002245:Carbon Dioxide; C011006:jasmonic acid; D002244:Carbon; D009584:Nitrogen