Increasing carbon availability stimulates growth and secondary metabolites via modulation of phytohormones in winter wheat.
Phytohormones play important roles in plant acclimation to changes in environmental conditions. However, their role in whole-plant regulation of growth and secondary metabolite production under increasing atmospheric CO2 concentrations ([CO2]) is uncertain but crucially important for understanding plant responses to abiotic stresses. We grew winter wheat (Triticum aestivum) under three [CO2] (170, 390, and 680 ppm) over 10 weeks, and measured gas exchange, relative growth rate (RGR), soluble sugars, secondary metabolites, and phytohormones including abscisic acid (ABA), auxin (IAA), jasmonic acid (JA), and salicylic acid (SA) at the whole-plant level. Our results show that, at the whole-plant level, RGR positively correlated with IAA but not ABA, and secondary metabolites positively correlated with JA and JA-Ile but not SA. Moreover, soluble sugars positively correlated with IAA and JA but not ABA and SA. We conclude that increasing carbon availability stimulates growth and production of secondary metabolites via up-regulation of auxin and jasmonate levels, probably in response to sugar-mediated signalling. Future low [CO2] studies should address the role of reactive oxygen species (ROS) in leaf ABA and SA biosynthesis, and at the transcriptional level should focus on biosynthetic and, in particular, on responsive genes involved in [CO2]-induced hormonal signalling pathways.
Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, D-07745, Jena, Germany.
Jianbei
J
Huang
Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, D-07745, Jena, Germany.
Michael
M
Reichelt
Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, D-07745, Jena, Germany.
Somak
S
Chowdhury
Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, D-07745, Jena, Germany.|Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa.
Almuth
A
Hammerbacher
Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, D-07745, Jena, Germany.
Henrik
H
Hartmann
D050260:Carbohydrate Metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D054046:Plant Stomata / Q000378:metabolism; D014908:Triticum / Q000254:growth & development / Q000378:metabolism*
D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D002245:Carbon Dioxide; C030737:indoleacetic acid
Abscisic acid; auxin; elevated CO2; jasmonic acid; low CO2; salicylic acid; secondary metabolites; soluble sugars.