Transposon mutant of Vigna radiata-nodulating Bradyrhizobium sp. impaired in both resistance to stress conditions and symbiotic performance

2011 ◽  
Vol 5 (25) ◽  
Author(s):  
Neelawan Pongsilp
Keyword(s):  
Vigna Radiata ◽  
Stress Conditions ◽  
Bradyrhizobium Sp ◽  
Resistance To Stress

scholarly journals Inactivation ofclpBin the Pathogen Leptospira interrogans Reduces Virulence and Resistance to Stress Conditions

2011 ◽  
Vol 79 (9) ◽  
pp. 3711-3717 ◽  
Author(s):  
Kristel Lourdault ◽  
Gustavo M. Cerqueira ◽  
Elsio A. Wunder ◽  
Mathieu Picardeau
Keyword(s):  
Oxidative Stress ◽  
Stress Conditions ◽  
Leptospira Interrogans ◽  
Wild Type ◽  
Content Type ◽  
General Stress Response ◽  
Growth Defects ◽  
Resistance To Stress ◽  
Increased Susceptibility

ABSTRACTLeptospira interrogansis the causative agent of leptospirosis, which is an emerging zoonotic disease. Resistance to stress conditions is largely uncharacterized for this bacterium. We therefore decided to analyze aclpBmutant that we obtained by random transposon mutagenesis. The mutant did not produce any of the two isoforms of ClpB. TheclpBmutant exhibited growth defects at 30° and 37°C and in poor nutrient medium and showed increased susceptibility to oxidative stress, whereas the genetically complemented strain was restored in ClpB expression andin vitrowild-type growth. We also showed that theclpBmutant was attenuated in virulence in an animal model of acute leptospirosis. Our findings demonstrate that ClpB is involved in the general stress response. The chaperone is also necessary, either directly or indirectly, for the virulence of the pathogenL. interrogans.

scholarly journals Effect of symbiotic association of rhizobia and endomycorrhizae from Moroccan arid littoral dunes on Acacia cyanophylla tolerance to drought

2018 ◽  
Vol 2 (2) ◽  
pp. 39-45
Author(s):  
ABDELHAKIM HATIMI ◽  
SAIDIA TAHROUCH ◽  
BRAHIM BOUIZGARNE
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
High Efficiency ◽  
Stress Conditions ◽  
Symbiotic Association ◽  
Positive Effects ◽  
Acacia Cyanophylla ◽  
Growth And Nutrition ◽  
Bradyrhizobium Sp ◽  
Rhizobium Sp

Hatimi A, Tahrouch S, Bouizgarne B. 2018. Effect of symbiotic association of rhizobia and endomycorrhizae from Moroccan arid littoral dunes on Acacia cyanophylla tolerance to drought. Asian J For 2: 39-45. The research on behavior of A. cyanophylla Lindl plants associated with a symbiotic indigenous endomycorrhizal fungi M, and three rhizobia isolates: two low growing isolate R1 (Bradyrhizobium sp. RCM6), and R2 (Bradyrhizobium sp. RLC3) and a fast-growing isolates R3 (Rhizobium sp. S21), originated from coastal dunes of the Souss-Massa region in drought stress conditions, was investigated in greenhouse. Results have clearly shown that the growth and nutrition of seedlings of A. cyanophylla were drastically affected after two months in drought stress conditions. However, inoculation of the symbiotic microorganisms either alone (treatments M, RMC6, R2 or R3) or as inoculums consisting of combination of the rhizobia with the endomycorrhiza (treatments MR1, MR2 or MR3) resulted in enhanced tolerance of A. cyanophylla seedlings to drought stress. At 100% of field capacity (fc), all treatments showed a significant improvement of plant growth compared to non-inoculated plants in stress conditions. In addition, we have shown that Bradyrhizobium RCM6 (R1) holds a high efficiency to improve the growth and nutrition of the host plant. Indeed, higher number of nodules/plant and higher amount of total nitrogen were recorded in the seedlings inoculated with Bradyrhizobium sp. RCM6 in comparison with plants inoculated with the two other rhizobia Bradyrhizobium sp. RLC3 (R2) and Rhizobium sp. S21 (R3), and control plants. Dual inoculation with each of the three rhizobia and the endomycorrhizal complex (M) led to higher water content (W.C) and relative water content (RWC) and a significant increase in Phosphorus content of the aerial part. While positive effects were recorded for Phosphorus, no such effects were recorded for nitrogen. However, the overall results showed the importance of the use of microorganisms in the dune coastal environment particularly adequate tripartite association: rhizobia Endomycorrhizes-A. cyanophylla in enhancing tolerance to drought stress.

scholarly journals Impact of water stress on physiological processes of moss Polytrichum piliferum Hedw.

2020 ◽  
pp. 129-141
Author(s):  
Małgorzata Romańska
Keyword(s):  
Water Stress ◽  
Dark Respiration ◽  
Living Conditions ◽  
Stress Conditions ◽  
Stress Factors ◽  
Tissue Hydration ◽  
Effect Of Water ◽  
Physiological Processes ◽  
Study Results ◽  
Resistance To Stress

Mosses are convenient organisms for studying the reaction to water stress because they do not have an epidermis, which makes them more sensitive to changes in humidity than most other plants. The aim of the study was to determine the effect of water stress on the course of physiological processes of mosses using Polytrichum piliferum Hedw. The present study showed that the action of the abiotic stressor, which is water, adversely affects the photosynthesis and dark respiration processes by reducing their intensity. However, it is worth noting that the respiration process is less dependent on tissue hydration than the photosynthesis, which is clearly demonstrated by the study results. The bryophytes’ resistance to stress factors is responsible for the plant’s ability to maintain homeostasis under stress conditions. The ability to change homeostasis by adapting, surviving or overcoming adverse living conditions also plays an important role.

scholarly journals Pollen viability of Tepary bean (Phaseolus acutifolius A. Gray.) mutant lines under water stress conditions and inoculation with rhizobia

2018 ◽  
Vol 67 (2) ◽  
pp. 319-325 ◽  
Author(s):  
Sergio Crespo-Muñoz ◽  
Mariela Rivera-Peña ◽  
Deisy Alexandra Rosero-Alpala ◽  
Jaime Eduardo Muñoz-Florez ◽  
Idupulapati M. Rao ◽  
...  
Keyword(s):  
Water Stress ◽  
Pollen Viability ◽  
Stress Conditions ◽  
Rhizobium Tropici ◽  
Tepary Bean ◽  
Phaseolus Acutifolius ◽  
Bradyrhizobium Sp ◽  
Mutant Lines

El fríjol tépari, Phaseolus acutifolius A. Gray destaca por su tolerancia al estrés por sequía y altas temperaturas, sin embargo, presenta baja diversidad genética en sus formas cultivadas. Por lo que se inició un programa de inducción de mutaciones. El objetivo de este estudio fue establecer el efecto de diferentes parámetros  agro-morfofisiológicos asociados sobre la viabilidad y cantidad del polen en 123 líneas mutantes de la quinta generación M5 de P. acutifolius y genotipos parentales, por medio del procesamiento de microfotografías de preparaciones de polen con tinción de acetocarmin. El experimento se realizó en condiciones de invernadero y el diseño experimental fue de subparcelas divididas con 3 repeticiones; adicionalmente, los factores evaluados fueron: condiciones de humedad del suelo, inoculación con cepas de Bradyrhizobium sp. o Rhizobium tropici, y las líneas o accesiones evaluadas (6 mutantes y 2 no mutantes). El experimento fue realizado manteniendo la temperatura nocturna superior a 25°C. No hubo diferencias significativas entre los tratamientos, se encontraron correlaciones positivas de la viabilidad de polen con otras variables. 

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