Gil Quintana, ErenaLarrainzar Rodríguez, EstíbalizSeminario Huárriz, AmaiaDíaz Leal, Juan LuisAlamillo, Josefa M.Pineda, ManuelArrese-Igor Sánchez, CésarWienkoop, StefanieGonzález García, Esther2017-04-112017-04-1120130022-0957 (Print)1460-2431 (Electronic)10.1093/jxb/ert074https://academica-e.unavarra.es/handle/2454/24069Drought stress is a major factor limiting symbiotic nitrogen fixation (NF) in soybean crop production. However, the regulatory mechanisms involved in this inhibition are still controversial. Soybean plants were symbiotically grown in a split-root system (SRS), which allowed for half of the root system to be irrigated at field capacity while the other half remained water deprived. NF declined in the water-deprived root system while nitrogenase activity was maintained at control values in the well-watered half. Concomitantly, amino acids and ureides accumulated in the water-deprived belowground organs regardless of transpiration rates. Ureide accumulation was found to be related to the decline in their degradation activities rather than increased biosynthesis. Finally, proteomic analysis suggests that plant carbon metabolism, protein synthesis, amino acid metabolism, and cell growth are among the processes most altered in soybean nodules under drought stress. Results presented here support the hypothesis of a local regulation of NF taking place in soybean and downplay the role of ureides in the inhibition of NFapplication/pdfeng© The Author(2) [2013]. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com.DroughtLocal regulationN-feedback inhibitionNitrogen fixationProteomicsSoybeanUreidesinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess