Elevated CO₂ changes the interactions between nematode and tomato genotypes differing in the JA pathway

• Published in: Plant, cell and environment cell and environment, 2010-05, Vol.33 (5), p.729-739
• Main Authors: SUN, YUCHENG, CAO, HAIFENG, YIN, JIN, KANG, LE, GE, FENG
• Format: Article
• Language: English
• Subjects: Animals; Antioxidants - metabolism; Biological and medical sciences; Biomass; Carbon - metabolism; Carbon Dioxide - metabolism; Cyclopentanes; elevated CO; elevated CO2; Fundamental and applied biological sciences. Psychology; Genotype; Host-Parasite Interactions; jasmonic acid; Lycopersicon esculentum - genetics; Lycopersicon esculentum - parasitology; Meloidogyne incognita; Mutation; Nitrogen - metabolism; Oxylipins; Plant Leaves - growth & development; Plant Roots - growth & development; Plants, Genetically Modified - genetics; Plants, Genetically Modified - parasitology; tomato mutants; Tylenchoidea - physiology; volatile organic compounds; Volatile Organic Compounds - metabolism
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/j.1365-3040.2009.02098.x

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.