Oxidative stress in the root nodules of Phaseolus vulgaris is induced under conditions of phosphorus deficiency

Abstract

One of the most adverse effects of phosphorus (P) deficiency on N-2-fixing legumes is the generation of harmful active oxygen species which cause oxidative stress. And although oxidative stress has been widely studied in roots and shoots of various plant species, it has not yet sufficiently been documented in bean nodules so far. In this study, two recombinant inbred lines RIL115 (P-deficiency tolerant) and RIL147 (P-deficiency sensitive) of common bean and Concesa (local variety) were inoculated separately with the reference strain R. tropici CIAT899, RhM11 (R. gallicum) or RhM14 (R. tropici); two local strains of the Marrakesh region of Morocco. Nodulated plants were grown under semi-hydroponic conditions with sufficient or deficient P supply and analyzed for their oxidative responses at the flowering stage. The results indicated that P-deficiency decreased the growth of shoots (48 %) and nodules (32 %), particularly with RhM14 exhibiting the highest decrease (52 %) of nodulation. This constraint increased electrolyte leakage of nodules (40 %) as compared to leaves (20 %), especially for plants inoculated with RhM14 and CIAT899. Moreover, high H2O2 and malondialdehyde contents were noticed in P-deficient nodules of RhM14 and RhM11. These variations were associated with peroxidase activity stimulation in P-deficient nodules induced by CIAT899 and RhM14. In symbiosis with RIL115, these last strains exhibited the highest nodule phenol content. Overall, phenol content was mainly enhanced in P-deficient nodules (35 %) as compared to the leaves (16 %). It was concluded that the genotypes inoculated with CIAT899 and RhM11 are relatively P-deficiency tolerant combinations as compared to those inoculated with RhM14. Increase of oxidative stress in nodules rather than in leaves points to the need for further investigations of mechanisms that improve the root-nodule efficiency under adverse conditions

Comparative transcriptome analysis of nodules of two Mesorhizobium–chickpea associations with differential symbiotic efficiency under phosphate deficiency

“…Nodules have the potential to generate high levels of ROS due to high rates of bacteroid respiration, the oxidation of several proteins (nitrogenase, ferredoxin and hydrogenase) with strong reducing potentials, and autoxidation of the oxygenated form of leghemoglobin (Becana et al ., ). Oxidative stress is known to be a critical factor associated with Pi deficiency, and is caused by the overproduction of harmful ROS in the nodules of N 2 ‐fixing legumes when nodule metabolism is disturbed by either a biotic or abiotic stressor (Bargaz et al ., ). In a previous study, it was suggested that Pi deficiency‐induced oxidative stress may be implicated in down‐regulating the SNF capacity in Mm SWRI9‐inoculated plants (Nasr Esfahani et al ., ).…”

Effect of drought on growth, physiological and biochemicalprocesses of chickpea-rhizobia symbiosis

“…Seven days after, the seedlings were inoculated with 10 mL of each strain of rhizobia Containing approximately 10 8 CFU/mL (CFU = Colony-forming unit). Plants were watered three times a week with the distillated water and the nitrogen free nutrient solution during the trial period (Bargaz et al 2013). After one week, plants randomly selected were subjected to maximal irrigation (100%), optimal irrigation (FC 1 : 80% of field capacity) and under water deficit (FC 2 : 40% of field capacity).…”

Specific expression and activity of acid phosphatases in common bean nodules

“…5 The latter, with carbon supply regulation and N feedback, contribute to regulating SNF. 43 Moreover, oxidative stress is not induced only under P-deficiency, 34,44 but also in response to high P concentration in nodules where respiration is expected to be not associated to SNF. [5][6][7][8][9][10][11][12][13][14][15][16] This is evidenced by the absence of correlation between the efficiency in use of rhizobial symbiosis and SNF.…”