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Differential CO2 effect on primary carbon metabolism of flag leaves in durum wheat (Triticum durum Desf.)

Aranjuelo, Iker, Erice, Gorka, Sanz‐Sáez, Alvaro, Abadie, Cyril, Gilard, Françoise, Gil‐Quintana, Erena, Avice, Jean‐Christophe, Staudinger, Christiana, Wienkoop, Stefanie, Araus, Jose L., Bourguignon, Jacques, Irigoyen, Juan J., Tcherkez, Guillaume
Plant, cell and environment 2015 v.38 no.12 pp. 2780-2794
filling period, flowering, durum wheat, acclimation, carbon, carbon sinks, stable isotopes, carbon dioxide, electron transfer, photosynthesis, mesophyll, nutrient use efficiency, metabolomics, leaves, cultivars, lysine, carboxylation, Triticum turgidum subsp. durum, proteomics, biomass, ribulose-bisphosphate carboxylase, proteins, nitrogen
C sink/source balance and N assimilation have been identified as target processes conditioning crop responsiveness to elevated CO₂. However, little is known about phenology‐driven modifications of C and N primary metabolism at elevated CO₂ in cereals such as wheat. Here, we examined the differential effect of elevated CO₂ at two development stages (onset of flowering, onset of grain filling) in durum wheat (Triticum durum, var. Sula) using physiological measurements (photosynthesis, isotopes), metabolomics, proteomics and ¹⁵N labelling. Our results show that growth at elevated CO₂ was accompanied by photosynthetic acclimation through a lower internal (mesophyll) conductance but no significant effect on Rubisco content, maximal carboxylation or electron transfer. Growth at elevated CO₂ altered photosynthate export and tended to accelerate leaf N remobilization, which was visible for several proteins and amino acids, as well as lysine degradation metabolism. However, grain biomass produced at elevated CO₂ was larger and less N rich, suggesting that nitrogen use efficiency rather than photosynthesis is an important target for improvement, even in good CO₂‐responsive cultivars.