Combined use of δ¹³C, δ18O and δ15N tracks nitrogen metabolism and genotypic adaptation of durum wheat to salinity and water deficit.
• Accurate phenotyping remains a bottleneck in breeding for salinity and drought resistance. Here the combined use of stable isotope compositions of carbon (δ¹³C), oxygen (δ¹⁸O) and nitrogen (δ¹⁵N) in dry matter is aimed at assessing genotypic responses of durum wheat under different combinations of these stresses. • Two tolerant and two susceptible genotypes to salinity were grown under five combinations of salinity and irrigation regimes. Plant biomass, δ¹³C, δ¹⁸O and δ¹⁵N, gas-exchange parameters, ion and N concentrations, and nitrate reductase (NR) and glutamine synthetase (GS) activities were measured. • Stresses significantly affected all traits studied. However, only δ¹³C, δ¹⁸O, δ¹⁵N, GS and NR activities, and N concentration allowed for clear differentiation between tolerant and susceptible genotypes. Further, a conceptual model explaining differences in biomass based on such traits was developed for each growing condition. • Differences in acclimation responses among durum wheat genotypes under different stress treatments were associated with δ¹³C. However, except for the most severe stress, δ¹³C did not have a direct (negative) relationship to biomass, being mediated through factors affecting δ¹⁸O or N metabolism. Based upon these results, the key role of N metabolism in durum wheat adaptation to salinity and water stress is highlighted.
Unitat de Fisiologia Vegetal, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain.
Salima
S
Yousfi
Unitat de Fisiologia Vegetal, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain.
Maria Dolores
MD
Serret
Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Spain.
Antonio José
AJ
Márquez
Departament de Producció Vegetal i Ciència Forestal, Universitat de Lleida, Lleida, Spain.
Jordi
J
Voltas
Unitat de Fisiologia Vegetal, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain.|International Maize and Wheat Improvement Center (CIMMYT), El Batan, Mexico.
José Luis
JL
Araus
D000222:Adaptation, Physiological / Q000235:genetics*; D018533:Biomass; D002247:Carbon Isotopes; D016000:Cluster Analysis; D055864:Droughts; D005838:Genotype; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D007477:Ions; D016014:Linear Models; D050901:Nitrate Reductase / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D010103:Oxygen Isotopes; D010788:Photosynthesis; D018520:Plant Shoots / Q000254:growth & development; D019655:Quantitative Trait, Heritable; D054712:Salinity; D014908:Triticum / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D014867:Water / Q000378:metabolism*
D002247:Carbon Isotopes; D007477:Ions; D009587:Nitrogen Isotopes; D010103:Oxygen Isotopes; D014867:Water; D050901:Nitrate Reductase; D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen