Differential CO2 effect on primary carbon metabolism of flag leaves in durum wheat (Triticum durum Desf.)
2015
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
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.
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