Effect of the co-inoculation of lucerne (Medicago sativa l.) with Sinorhizobium meliloti and Herbaspirillum frisingense in relation to the interactions between bacterial strain (original) (raw)
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American-Eurasian Journal of Agricultural and Environmental Science, 2009
This study evaluated the effects of co-inoculation with Sinorhizobium meliloti and arbuscular mycorrhizal fungi on the growth, yield and biological nitrogen fixation (BNF) of lucerne (Medicago sativa L.) under organic farming and dry weather conditions. The trial was laid out as a factorial experiment in the fields of the University of Natural Resources and Applied Life Sciences, Vienna-Austria at Raasdorf in 2007. The experimental factors of S. meliloti and arbuscular mycorrhiza (AM) including Glomus etunicatum, G. intraradices and G. claroideum and irrigation levels were tested. Co-inoculation of lucerne with S. meliloti and AM increased shoot dry weight as well as BNF at the first and second harvest but for BNF it was not significant. Irrigation resulted in the enhanced growth of some growth parameters. Microbial activities in this organically managed field were high enough for establishing an effective symbiosis with lucerne without any necessity for inoculation. Hence, it can b...
2012
Salinity is among important soil stresses adversely affecting the process of nitrogen (N) fixation in leguminous plants in different parts of the world. It has been indicated that salinity can inhibit the early stages of nodulation process between bacterium and the host plant including the exchange of signal molecules ( nod gene inducers). There has not been any research regarding the effects of nod gene inducers on the growth of alfalfa inoculated with Sinorhizobium meliloti under saline conditions. A growth chamber experiment was conducted to determine the effects of pre-incubation of S. meliloti with effective inducers of nod genes Luteolin, Methyl jasmonate and Genistein on the growth and N-fixation of two different alfalfa ( Medicago sativa L.) cultivars (Yazdi and Hamedani) under salt stress. Nod gene inducers increased alfalfa growth and N fixation under normal as well as under salt stressed conditions. Yazdi cultivar showed to be more tolerant to salinity than Hamedani with ...
Co-Inoculation of Soybean with Bradyrhizobium and Azospirillum Promotes Early Nodulation
American Journal of Plant Sciences, 2015
Soybean inoculation with elite strains of Bradyrhizobium to improve nodulation, N2 fixation, and grain yield is well established worldwide. However, when grown in soils where N is deficient, soybean undergoes an initial phase of N starvation that may last up to 20 days after seedling germination due to the lack of synchronism between the phase when seed N reserves are exhausted and the moment when plants begin to benefit from the nitrogen fixed by the bacteria. Practices that promote early nodulation may play a key role in reducing the N starvation period. Azospirillum is a plant growth promoting rhizobacteria (PGPR) that can stimulate root hair formation and root growth, creating more sites for early root infection and nodule formation by N2-fixing Bradyrhizobium spp. In this study, the effects of co-inoculating soybeans with Bradyrhizobium spp. and Azospirillum brasilense on nodulation precocity and N2 fixation were evaluated under greenhouse and field conditions. Nodule number and dry weight, as well as plant and root dry weight and N accumulated in shoots at 15, 18, 21, 24 and 30 days after emergence (DAE) were evaluated in response to inoculation with Bradyrhizobium spp. alone or when co-inoculated with Azospirillum sp. In the greenhouse, co-inoculated plants nodulated precociously as indicated by a significant increase (p < 0.05) in nodule biomass observed at (include) 21 DAE. More pronounced effects of co-inoculation were observed in the field as early as 18 DAE, suggesting that the presence of Azospirillum helps plants to overcome environmental stresses.
Co-Inoculation of Soybean with Bradyrhizobium and Azospirillum Promotes Early Nodulation
Soybean inoculation with elite strains of Bradyrhizobium to improve nodulation, N2 fixation, and grain yield is well established worldwide. However, when grown in soils where N is deficient, soybean undergoes an initial phase of N starvation that may last up to 20 days after seedling germination due to the lack of synchronism between the phase when seed N reserves are exhausted and the moment when plants begin to benefit from the nitrogen fixed by the bacteria. Practices that promote early nodulation may play a key role in reducing the N starvation period. Azospirillum is a plant growth promoting rhizobacteria (PGPR) that can stimulate root hair formation and root growth, creating more sites for early root infection and nodule formation by N2-fixing Bradyrhizobium spp. In this study, the effects of co-inoculating soybeans with Bradyrhizobium spp. and Azospirillum brasilense on nodulation precocity and N2 fixation were evaluated under greenhouse and field conditions. Nodule number and dry weight, as well as plant and root dry weight and N accumulated in shoots at 15, 18, 21, 24 and 30 days after emergence (DAE) were evaluated in response to inoculation with Bradyrhizobium spp. alone or when co-inoculated with Azospirillum sp. In the greenhouse, co-inoculated plants nodulated precociously as indicated by a significant increase (p < 0.05) in nodule biomass observed at (include) 21 DAE. More pronounced effects of co-inoculation were observed in the field as early as 18 DAE, suggesting that the presence of Azospirillum helps plants to overcome environmental stresses.
American Journal of Plant Sciences, 2015
Soybean inoculation with elite strains of Bradyrhizobium to improve nodulation, N2 fixation, and grain yield is well established worldwide. However, when grown in soils where N is deficient, soybean undergoes an initial phase of N starvation that may last up to 20 days after seedling germination due to the lack of synchronism between the phase when seed N reserves are exhausted and the moment when plants begin to benefit from the nitrogen fixed by the bacteria. Practices that promote early nodulation may play a key role in reducing the N starvation period. Azospirillum is a plant growth promoting rhizobacteria (PGPR) that can stimulate root hair formation and root growth, creating more sites for early root infection and nodule formation by N2-fixing Bradyrhizobium spp. In this study, the effects of co-inoculating soybeans with Bradyrhizobium spp. and Azospirillum brasilense on nodulation precocity and N2 fixation were evaluated under greenhouse and field conditions. Nodule number and dry weight, as well as plant and root dry weight and N accumulated in shoots at 15, 18, 21, 24 and 30 days after emergence (DAE) were evaluated in response to inoculation with Bradyrhizobium spp. alone or when co-inoculated with Azospirillum sp. In the greenhouse, co-inoculated plants nodulated precociously as indicated by a significant increase (p < 0.05) in nodule biomass observed at (include) 21 DAE. More pronounced effects of co-inoculation were observed in the field as early as 18 DAE, suggesting that the presence of Azospirillum helps plants to overcome environmental stresses.
Biotechnology Reports, 2020
Coinoculation of plants with mixtures of beneficial microbes sometimes produces synergistic effects. In this study, the effect of soybean coinoculation with the N 2-fixing Bradyrhizobium japonicum E109 and the biocontrol fungus Trichoderma harzianum Th5cc was analyzed. Nodulation by E109 was not hampered by Th5cc, which antagonized five out of seven soybean pathogens tested. Furthermore, Th5cc relieved nitrate-inhibition of nodulation, enabling the formation of nodules containing infected cells with bacteroids in the presence of the otherwise inhibitory 10 mM KNO 3. Th5cc released micromolar amounts of auxin, and addition of 11 mM indoleacetic acid to soybean plants inoculated with E109 in the absence of Th5cc also induced nodulation in the presence of 10 mM KNO 3. Thus, Th5cc may release auxins into the soybean rhizosphere, which hormones might participate in overcoming the nitrate-inhibition of nodulation. Our results suggest that soybean plants coinoculated with these microorganisms might benefit from biocontrol while contributing to soil-nitrogen preservation.
Microbial Stimulation of Growth of Lucerne
From the soil samples outside the areas of intensive agriculture, were allocated 145 isolates: 80 cultures growing on medium nutrient agar, 28on 79 medium for fixing microorganisms and 37 isolates on MRS medium, by forming zones of hydrolysis of chalk. The influence of selected microorganisms were researched on seed germination and seedling growth of lucerne. Stimulation of the growth of lucerne by some cultures reached 35% (5, R11) -45% (1, 9, R5, R28) compared with the control.
Acta Physiologiae Plantarum, 2021
Symbiosis between plants of family Fabaceae and bacteria genus Rhizobium is the most widespread interaction, in which atmospheric nitrogen is reduced into ammonia. This highly oxygen-sensitive process is performed by endosymbiotc forms of rhizobia called bacteroids, which occupy newly formed plant organs called root nodules. The goal in this paper was to explore the differences in the (ultra)structure and Reactive Oxygen Species (ROS) localization in two symbiotic interactions between legume model plant Medicago truncatula Gaertn. and bacteria from genus Sinorhizobium . Two bacterial strains— Sinorhizobium meliloti 1021 and Sinorhizobium medicae 419 have the ability of inducing root nodules on the Medicago truncatula , however, such nodules differ in effectiveness of biological nitrogen fixation. We demonstrated that root nodules made of S. medicae 419 [fully effective (F++)] induce a lower number of nodule per plant in comparison to S. meliloti 1021—(partially effective F±). Althou...
Journal of Experimental Botany, 2004
Medicago truncatula is a model legume plant that interacts symbiotically with Sinorhizobium meliloti, the alfalfa symbiont. This process involves a molecular dialogue between the bacterium and the plant. Legume roots exude flavonoids that induce the expression of a set of rhizobial genes, the nod genes, which are essential for nodulation and determination of the host range. In turn, nod genes control the synthesis of lipo-chito-oligosaccharides (LCOs), Nod factors, which are bacteria-to-plant signal molecules mediating recognition and nodule organogenesis. M. truncatula roots or seeds have been treated with Nod factors and hydroponically growing seedlings have been inoculated with a limiting population of S. meliloti. It has been shown that submicromolar concentrations of Nod factors increase the number of nodules per plant on M. truncatula. Compared with roots, this increase is more noticeable when seeds are treated. M. truncatula seeds are receptive to submicromolar concentrations of Nod factors, suggesting the possibility of a high affinity LCO perception system in seeds or embryos as well.
Background and aims Endophytic actinobacteria are known to benefit their hosts by improving plant growth and by reducing the severity of soil borne diseases. In this study, their role in enhancing the growth of lucerne and their interaction with its rhizobial symbiosis is examined. Comparison is made between endophytic actinobacteria isolated from wheat plants and isolates from the roots and nodules of four different legume species: lucerne (Medicago sativa L.), field pea (Pisum sativum L.), subterranean clover (Trifolium subterraneum L.) and burr medic (Medicago polymorpha L.). Methods Two hundred and twenty five isolates of actinobacteria were recovered from the legumes. Five selected legume isolates were compared to five wheat isolates for their effects on rhizobial growth on agar and on the early nodulation and growth of lucerne plants inoculated with Sinorhizobium meliloti strain RRI 128. Results Co-inoculation with lucerne isolates Streptomyces spp. LuP30 and LuP47B, increased lucerne shoot dry weight at 7 weeks after inoculation by 25 to 35 %, and shoot nitrogen content by 22 to 28 % respectively, compared to plants treated with Sinorhizobium meliloti RRI 128 alone. Conclusions This study shows that some endophytic actinobacteria have the potential to enhance the lucerne rhizobia symbiosis.