Nitrogen availability impacts oilseed rape (Brassica napus L.) plant water status and proline production efficiency under water-limited conditions

• Published in: Planta Vol. 236; no. 2; pp. 659 - 676
• Main Authors: Albert, Benjamin, Le Cahérec, Françoise, Niogret, Marie-Françoise, Faes, Pascal, Avice, Jean-Christophe, Leport, Laurent, Bouchereau, Alain
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.08.2012; Springer; Springer Nature B.V; Springer Verlag
• Subjects: Agriculture; Amino acids; Biological and medical sciences; Biological Transport - physiology; Biomedical and Life Sciences; Brassica napus - drug effects; Brassica napus - genetics; Brassica napus - physiology; Chlorophyll - analysis; Chlorophyll - metabolism; Chlorophylls; Dehydration; Drought; Ecology; Forestry; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant - physiology; Leaves; Life Sciences; Nitrogen; Nitrogen - pharmacology; Oilseeds; Original; Original Article; Phenotype; Phloem; Phloem - drug effects; Phloem - genetics; Phloem - physiology; Plant Leaves - drug effects; Plant Leaves - genetics; Plant Leaves - physiology; Plant Proteins - genetics; Plant Roots - drug effects; Plant Roots - genetics; Plant Roots - physiology; Plant Sciences; Plant Stomata - drug effects; Plant Stomata - genetics; Plant Stomata - physiology; Plant Transpiration; Plants; Proline - analysis; Proline - metabolism; RNA, Plant - genetics; Seedlings - drug effects; Seedlings - genetics; Seedlings - physiology; Stress, Physiological; Water - metabolism; Water shortages; Drought stress; Nitrogen supply; Proline metabolism; Water status; Source-sink relationship; Nitrogen fertilization; Brassica napus var. oleifera; Water deficit; Available nutrient; Plant biology; Proline; Water stress; Cruciferae; Efficiency; Water regime; Dicotyledones; Angiospermae; Production; Drought; Nitrogen; Metabolism; Source sink relationship; Brassica napus; Spermatophyta; Oil plant (vegetal); P5CS GENES; CHLOROPHYLL FLUORESCENCE; DROUGHT STRESS; LEAVES; LEAF SENESCENCE; STOMATAL CONDUCTANCE; METABOLISM; AMINO-ACIDS; GLUTAMINE-SYNTHETASE; ACCUMULATION
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-012-1636-8

Large amounts of nitrogen (N) fertilizers are used in the production of oilseed rape. However, as low-input methods of crop management are introduced crops will need to withstand temporary N deficiency. In temperate areas, oilseed rape will also be affected by frequent drought periods. Here we evaluated the physiological and metabolic impact of nitrate limitation on the oilseed rape response to water deprivation. Different amounts of N fertilizer were applied to plants at the vegetative stage, which were then deprived of water and rehydrated. Both water and N depletion accelerated leaf senescence and reduced leaf development. N-deprived plants exhibited less pronounced symptoms of wilting during drought, probably because leaves were smaller and stornata were partially closed.囎Efficiency of proline production, a major stress-induced diversion of nitrogen metabolism, was assessed at different positions along the whole plant axis and related to leaf developmental stage and water status indices. Proline accumulation, preferentially in younger leaves, accounted for 25-85 % of the free amino acid pool. This was mainly due to a better capacity for proline synthesis in fully N-supplied plants whether they were subjected to drought or not, as deduced from the expression patterns of the proline metabolism BnP5CS and BnPDH genes. Although less proline accumulated in the oldest leaves, a significant amount was transported from senescing to emerging leaves. Moreover, during rehydration proline was readily recycled. Our results therefore suggest that proline plays a significant role in leaf N remobilization and in N use efficiency in oilseed rape.