Local inhibition of nitrogen fixation and nodule metabolism in drought-stressed soybean

• Published in: Journal of experimental botany Vol. 64; no. 8; pp. 2171 - 2182
• Main Authors: Gil-Quintana, Erena, Larrainzar, Estíbaliz, Seminario, Amaia, Díaz-Leal, Juan Luis, Alamillo, Josefa M, Pineda, Manuel, Arrese-Igor, Cesar, Wienkoop, Stefanie, González, Esther M
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press [etc.] 01.05.2013; Oxford University Press
• Subjects: Agronomy. Soil science and plant productions; amino acid metabolism; Amino acids; Amino Acids - analysis; Amino Acids - metabolism; Biological and medical sciences; biosynthesis; Botany; carbon; cell growth; crop production; Drought; Droughts; Economic plant physiology; field capacity; Fundamental and applied biological sciences. Psychology; Glycine max - chemistry; Glycine max - metabolism; Glycine max - physiology; Legumes; Nitrogen fixation; Nitrogen Fixation - physiology; nitrogenase; Nodules; Parasitism and symbiosis; Physiological regulation; Plant physiology and development; Plant Root Nodulation - physiology; Plant Transpiration - physiology; Plants; protein synthesis; Proteomics; RESEARCH PAPER; Root systems; Soybeans; Stress, Physiological - physiology; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); transpiration; Urea - analysis; Urea - metabolism; ureides; water stress; local regulation; Ureide; Feedback regulation; Plant nodule; Soybean; Metabolism; Glycine max; Water stress; N-feedback inhibition; Grain legume; ureides; Leguminosae; Dicotyledones; Angiospermae; Botany; Proteomics; Nitrogen fixation; Spermatophyta; Inhibition; Drought; soybean; proteomics; nitrogen fixation
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ert074

Drought 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 NF.