Abstract
Most legume species establish a symbiotic association with soil bacteria. The plant accommodates the differentiated rhizobia in specialized organs, the root nodules. In this environment, the microsymbiont reduces atmospheric nitrogen (N) making it available for plant metabolism. Symbiotic N-fixation is driven by the respiration of the host photosynthates and thus constitutes an additional carbon sink for the plant. Molecular phenotypes of symbiotic and non-symbiotic Medicago truncatula are identified. The implication of nodule symbiosis on plant abiotic stress response mechanisms is not well understood. In this study, we exposed nodulated and non-symbiotic N-fertilized plants to salt and drought conditions. We assessed the stress effects with proteomic and metabolomic methods and found a nutritionally regulated phenotypic plasticity pivotal for a differential stress adjustment strategy.
Highlights
Reduced water availability will dramatically impact agricultural productivity in the 40 years
The effect of reduced water availability on plant performance was analyzed in order to assess the degree of stress as alterations in water status in both nutritional phenotypes in M. truncatula (N-fed and nitrogen fixing (N-fix); Table 1)
The effect of drought stress was significant for most of the analyzed parameters depending on nutritional status
Summary
Reduced water availability will dramatically impact agricultural productivity in the 40 years. According to demographic and climate change models, the human population will double by 2050 and the variability in rainfalls will increase (IPCC, 2007). We need a profound understanding of plant physiology and metabolism under water limiting conditions. Drought and salinity are environmental constraints accounting for substantial yield losses. Both decrease the amount of water available to plants, leading to reduced growth, and photosynthesis (Chaves et al, 2009). It has been proposed that early acclimatory responses to both stresses share strong commonalities (Munns, 2002)
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