scholarly journals Ecological and genetic bases for construction of highly effective nitrogen-fixing microbe-plant symbioses

2019 ◽  
Vol 17 (1) ◽  
pp. 11-18
Author(s):  
Nikolai A. Provorov ◽  
Olga P. Onishchuk
Keyword(s):  
Quantitative Traits ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Genetically Engineered ◽  
Nodule Bacteria ◽  
N Accumulation ◽  
Symbiotic Efficiency ◽  
Highly Effective ◽  
Nodulation Competitiveness ◽  
Complementary Interactions

Expression of quantitative traits characterizing the N2-fixing symbiosis of nodule bacteria and leguminous plants is associated with operation of the evolutionary derived polygenic systems controlling the symbiotic efficiency (SE) (impact of inoculation on the plant productivity) and nodulation competitiveness (NC) (formation of nodules by rhizobia under mixed inoculation). Optimization of balance between positive and negative symbiotic regulators aimed at an increase of nitrogenase activity and at a complete allocation of its products into the plant metabolism provides the generation of rhizobia strains with high SE and NC. Inactivation of the negative symbiotic regulators often results in a decreased survival of rhizobia under the edaphic stresses but is responsible for a balanced increase of plant biomass and N accumulation. Improvement of symbiotic activity is to be based on the complementary interactions of microorganisms with the genetically engineered plant cultivars which are able for selection from soil of actively fi xing N2 rhizobia strains and for their preferential multiplication in nodules. Construction of highly effective microbe-plant systems should be based on modifications of mechanisms controlling symbiosis development from the plant and bacterial sides providing the maintenance of N2-fixing zone in nodules and synthesis of NCR proteins activating the bacteroid differentiation.

Differential colonization by bioprospected rhizobial bacteria associated with common bean in different cropping systems

2017 ◽  
Vol 63 (8) ◽  
pp. 682-689
Author(s):  
Josiele Polzin de Oliveira-Francesquini ◽  
Mariangela Hungria ◽  
Daiani Cristina Savi ◽  
Chirlei Glienke ◽  
Rodrigo Aluizio ◽  
...  
Keyword(s):  
Common Bean ◽  
Plant Biomass ◽  
Cropping Systems ◽  
Root Nodules ◽  
Housekeeping Genes ◽  
Rrna Gene ◽  
N Fixation ◽  
N Accumulation ◽  
Symbiotic Efficiency ◽  
Plant Nitrogen

In this study, we evaluated the diversity of rhizobia isolated from root nodules on common bean (Phaseolus vulgaris) derived from Andean and Mesoamerican centers and grown under field and greenhouse conditions. Genetic characterization of isolates was performed by sequencing analyses of the 16S rRNA gene and 2 housekeeping genes, recA and glnII, and by the amplification of nifH. Symbiotic efficiency was evaluated by examining nodulation, plant biomass production, and plant nitrogen (N) accumulation. The influence of the environment was observed in nodulation capacity, where Rhizobium miluonense was dominant under greenhouse conditions and the Rhizobium acidisoli group prevailed under field conditions. However, strain LGMB41 fit into a separate group from the type strain of R. acidisoli in terms of multilocus phylogeny, implying that it could belong to a new species. Rhizobium miluonense LGMB73 showed the best symbiotic efficiency performance, i.e., with the highest shoot-N content (77.7 mg/plant), superior to the commercial standard strain (56.9 mg/plant). Biodiversity- and bioprospecting-associated studies are important to better understand ecosystems and to develop more effective strategies to improve plant growth using a N-fixation process.

scholarly journals Organic Materials and Their Chemically Extracted Humic and Fulvic Acids as Potential Soil Amendments for Faba Bean Cultivation in Soils with Varying CaCO3 Contents

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 205
Author(s):  
Ihab M. Farid ◽  
Mohamed A. El-Ghozoli ◽  
Mohamed H. H. Abbas ◽  
Dalia S. El-Atrony ◽  
Hassan H. Abbas ◽  
...  
Keyword(s):  
Humic Substances ◽  
Faba Bean ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Organic Amendments ◽  
Fulvic Acids ◽  
Mineral N ◽  
Randomized Design ◽  
Long Time ◽  
Factor C

Organic amendments are important sources of nutrients that release upon organic matter degradation, yet the stability of these organics in arid and semi-arid regions is relatively low. In contrast, humic substances (HS) are resistant to biodegradation and can keep nutrients in the soil available for the plant over a long time. Combinations between humic substances (HS) and mineral-N fertilizers are assumed to retain higher available nutrients in soils than those recorded for the sole application of either mineral or organic applications. We anticipate, however, that humic substances might not be as efficient as the organics from which they were extracted in increasing NP uptake by plants. To test these assumptions, faba bean was planted in a pot experiment under greenhouse conditions following a complete randomized design while considering three factors: two soils (calcareous and non-calcareous, Factor A), two organics (biogas and compost, Factor B) and combinations of the organics and their extracts (HA or FA) together with complementary doses of mineral-N ((NH4)2SO4) to attain a total rate of 50 kg N ha−1 (the recommended dose for faba bean plants) (Factor C). Results indicated that nitrogenase activity increased significantly due to the application of the used organics. In this respect, compost manure caused higher nitrogenase activity than biogas manure did. Humic substances raised NP-availability and the uptake by plants significantly; however, the values of increase were lower than those that occurred due to the compost or biogas manure. Moreover, the sole application of the used organics recorded the highest increases in plant biomass. Significant correlations were also detected between NP-availability, uptake and plant biomass. This means that HS could probably retain nutrients in available forms for long time periods, yet nutrients released continuously but slowly upon decomposition of organics seemed more important for plant nutrition.

Effect of weed management on weeds, and on the nodulation, nitrogenase activity, growth and yield of pea (Pisum sativum)

2006 ◽  
Vol 54 (4) ◽  
pp. 469-485 ◽  
Author(s):  
G. Singh ◽  
D. Wright
Keyword(s):  
Pisum Sativum ◽  
Nitrogen Content ◽  
Weed Management ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Strong Relationship ◽  
Dry Weight ◽  
Growth And Yield ◽  
N Content ◽  
Shoot Dry Weight

Effects of one pre-emergence herbicide (terbutryn/terbuthylazine) and one post-emergence herbicide (bentazone) along with unweeded and hand-weeded controls on weeds and on the nodulation, nitrogenase activity, nitrogen content, growth and yield of pea (Pisum sativum) were studied. Terbutryn/terbuthylazine was applied pre-emergence @ 1.40, 2.80 and 5.60 kg/hawhereas bentazone was sprayed 6 weeks after sowing @ 1.44, 2.88 and 5.76 kg/h. Terbutryn/terbuthylazine controlled all the weeds very effectively, whereas bentazone did not control some weeds such as Polygonum aviculare, Poa annua and Elymus repens. The herbicides decreased the number of nodules, the dry weight of nodules, the nitrogenase activity, the shoot dry weight, the nitrogen content in the straw and seeds, and the seed yield of peas, the effects generally being higher at higher rates of application. The adverse effects of herbicides on these parameters might be due to their effects on plant growth, as both the herbicides are known to adversely affect photosynthesis. Nitrogenase activity did not correlate well with plant-N content or shoot dry weight. However, there was a strong relationship between plant biomass and plant-N content, which suggests that researchers can rely on these parameters for studying the effects of treatments on nitrogen fixation, rather than measuring nitrogenase activity.

Bacillus cereus UW85 inoculation effects on growth, nodulation, and N accumulation in grain legumes: Field studies

2002 ◽  
Vol 82 (2) ◽  
pp. 291-298 ◽  
Author(s):  
W. John Bullied ◽  
Terry J. Buss ◽  
J. Kevin Vessey
Keyword(s):  
Bacillus Cereus ◽  
Common Bean ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Field Studies ◽  
Grain Legumes ◽  
N Accumulation ◽  
N Content ◽  
Stimulation Of

Bacillus cereus strain UW85 was assessed for growth-promotion effects on soybean and common bean in the presence and absence of rhizobial inoculation at two field sites in Manitoba in 1994. Growth promotions due to B. cereus UW85 occurred for soybean only, and only at one site. Promotions in plant emergence in soybean were apparent at 60 d after planting (DAP), but stimulations in shoot dry weight (DW), N concentration, and N content were not apparent until 90 DAP. At maturity (120 DAP), inoculation with UW85 resulted in stimulation of seed yield by 9% and seed N content by 14%. However, stimulation in growth and N parameters by UW85 treatment was proportionally greater in the absence of B. japonicum inoculation than in the presence of the rhizobial inoculant. These observations, in combination with the observations that nitrogenase activity was not stimulated by UW85 treatment, clearly indicate that the UW85-mediated stimulation of growth and N accumulation of soybean is via a generalized stimulation of plant growth, and not via a stimulation in the soybean-B. japonicum symbiosis per se. Overall, our study indicates that inoculation with UW85 has the potential of increasing soybean production in western Canada, but these effects are site specific and are not seen in common bean. Key words: Bacillus cereus UW85, common bean, Glycine max, growth-promotion, Phaseolus vulgaris, soybean

Effects of Fire on the Growth, Nutrient Content and Rate of Nitrogen Fixation of the Cycad Macrozamia riedlei

1980 ◽  
Vol 28 (3) ◽  
pp. 271 ◽  
Author(s):  
TS Grove ◽  
AM O'connell ◽  
N Malajczuk
Keyword(s):  
Nitrogen Fixation ◽  
Forest Ecosystem ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Leaf Growth ◽  
Nutrient Content ◽  
Nitrogen And Phosphorus ◽  
Eucalyptus Marginata ◽  
Plant Parts ◽  
Coralloid Roots

The response of Macrozamia riedlei(Gaud.) C.A. Gardn. to fire, and its contribution to the input of nitrogen to the jarrah (Eucalyptus marginata Donn ex Sm.) forest ecosystem of south-western Australia, were studied by measuring the biomass and nutrient content of plant parts, and the nitrogenase activity of coralloid roots, in relation to time since burning. Leaf growth was rapid during the first year following fire. In forest burnt 1-5 years previously, the ratio of weight of leaves to weight of bole did not differ significantly between sites. On a site burnt 7 years previously a reduced proportion of leaves in the total plant biomass was attributed to a yellowing and senescence of leaves. The ratio of weight of coralloid roots to weight of boles was greatest on the most recently burnt site. Concentrations of nitrogen and phosphorus in leaves, and phosphorus, potassium and zinc in coralloid roots, were significantly higher in plants growing in recently burnt forest. Concentrations of calcium, sodium and chlorine in leaves were higher on sites which had not been burnt recently. The rate of acetylene reduction, expressed per unit of bole weight, was greatest where forest had been burnt 1 year before sampling and decreased to a minimum where burning had occurred 7 years previously. This trend resulted from a decrease in both the weight and nitrogenase activity of coralloid roots with increasing time since burning. Estimated rates of nitrogen fixation were 8.4 and 1.4 kg ha-1 year-1 on sites burnt 1 . 5 and 7 years previously. In the period between successive prescribed burns (5 to 7 years), M. riedlei was estimated to fix c. 35 kg nitrogen ha-1. This appears to be a significant input in relation to the nitrogen balance of the jarrah forest ecosystem.

scholarly journals Comparative Study of the Effects of Salinity on Growth, Gas Exchange, N Accumulation and Stable Isotope Signatures of Forage Oat (Avena sativa L.) Genotypes

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1025
Author(s):  
Syed Sadaqat Shah ◽  
Zhijian Li ◽  
Hong Yan ◽  
Lianxuan Shi ◽  
Bangwei Zhou
Keyword(s):  
Salinity Tolerance ◽  
Avena Sativa ◽  
Plant Biomass ◽  
Water Status ◽  
Growth Cycle ◽  
Shoot Biomass ◽  
Saline Stress ◽  
N Accumulation ◽  
Forage Type ◽  
Four Levels

Identifying suitable salt stress-tolerant phenotypes based on their agronomic and physiological traits remains a herculean task in forage-type oat (Avena sativa L.) breeding. This study examined the responses of six forage-type oat cultivars under four levels of saline stress over the vegetative growth cycle. Crop growth, water status-related traits and nitrogen status-related traits were analyzed in different plant parts to evaluate effective approaches for identifying salt tolerance. Plant biomass, height, tiller number and culm thickness changed substantially during salinity, but they were not precise enough for use in estimating genotypic salinity tolerance during long-term stress. Genotypes bearing larger numbers of tillers showed greater sensitivity to salinity due to its effects on biomass loss. Tolerant genotypes exhibited higher relative shoot biomass together with higher water use efficiency. The concentrations of Na+, K+ and their ratio, combined with the δ13C in shoots and roots were effective indicators for estimating tolerant genotypes through better water maintenance. N concentrations of shoots were the most efficient for evaluating genotypic tolerance. Low nitrate reductase (NR) and glutamine synthetase (GS) activity might be key factors limiting N accumulation. Chlorophyll (Chl) content and net photosynthetic rate, as well as stomatal conductance and evaporation, were useful for identifying salinity tolerance physiological mechanisms, but the effectiveness was low for genotypic tolerance testing for forage type oats due to the interaction between genotypes and salinity levels. The selection of high salinity-tolerant genotypes should focus on genotypes with photosynthetic resilience to salt, followed by high N metabolism (higher NR and GS activities) to ensure accumulation of more N in the shoot dry matter.

scholarly journals Elucidating the Possible Involvement of Maize Aquaporins and Arbuscular Mycorrhizal Symbiosis in the Plant Ammonium and Urea Transport under Drought Stress Conditions

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 148 ◽  
Author(s):  
Gabriela Quiroga ◽  
Gorka Erice ◽  
Ricardo Aroca ◽  
Antonio Delgado-Huertas ◽  
Juan Manuel Ruiz-Lozano
Keyword(s):  
Drought Stress ◽  
Arbuscular Mycorrhizae ◽  
Plant Biomass ◽  
Net Photosynthesis ◽  
N Fertilization ◽  
Stress Conditions ◽  
Mycorrhizal Symbiosis ◽  
In Planta ◽  
N Accumulation ◽  
Am Symbiosis

This study investigates the possible involvement of maize aquaporins which are regulated by arbuscular mycorrhizae (AM) in the transport in planta of ammonium and/or urea under well-watered and drought stress conditions. The study also aims to better understand the implication of the AM symbiosis in the uptake of urea and ammonium and its effect on plant physiology and performance under drought stress conditions. AM and non-AM maize plants were cultivated under three levels of urea or ammonium fertilization (0, 3 µM or 10 mM) and subjected or not to drought stress. Plant aquaporins and physiological responses to these treatments were analyzed. AM increased plant biomass in absence of N fertilization or under low urea/ ammonium fertilization, but no effect of the AM symbiosis was observed under high N supply. This effect was associated with reduced oxidative damage to lipids and increased N accumulation in plant tissues. High N fertilization with either ammonium or urea enhanced net photosynthesis (AN) and stomatal conductance (gs) in plants maintained under well-watered conditions, but 14 days after drought stress imposition these parameters declined in AM plants fertilized with high N doses. The aquaporin ZmTIP1;1 was up-regulated by both urea and ammonium and could be transporting these two N forms in planta. The differential regulation of ZmTIP4;1 and ZmPIP2;4 with urea fertilization and of ZmPIP2;4 with NH4+ supply suggests that these two aquaporins may also play a role in N mobilization in planta. At the same time, these aquaporins were also differentially regulated by the AM symbiosis, suggesting a possible role in the AM-mediated plant N homeostasis that deserves future studies.

Bacillus cereus UW85 inoculation effects on growth, nodulation, and N accumulation in grain legumes: Controlled-environment studies

2002 ◽  
Vol 82 (2) ◽  
pp. 282-290 ◽  
Author(s):  
J. Kevin Vessey ◽  
Terry J. Buss
Keyword(s):  
Bacillus Cereus ◽  
Common Bean ◽  
Temperature Regime ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Controlled Environment ◽  
N Accumulation ◽  
Positive Effects ◽  
Whole Plant ◽  
Single Temperature

Treating seed with Bacillus cereus strain UW85 stimulates nodulation in soybean, but the underlying mechanisms of this stimulation are poorly understood. In this study we assessed the effects of inoculation on nodulation, nitrogenase activity and dry matter partitioning in soybean (cv. Maple Ridge), common bean (cv. OAC Rico) and pea (cv. Express) under controlled, gnotobiotic conditions. Plants were grown for 34 d under controlled-environment conditions without a mineral N source, at low two levels of (brady)rhizobia inoculation. Soybean and common bean were grown at a single temperature regime and pea was grown at two temperature regimes. Each trial consisted of five treatments (noninoculated control, low (brady)rhizobia inoculation, low (brady)rhizobia plus UW85 inoculation, high (brady)rhizobia inoculation, and high (brady)rhizobia plus UW85 inoculation) with six plants as replicates per treatment in a completely randomized design. Inoculation of soybean with UW85 increased growth of roots, shoots, and nodules across both levels of bradyrhizobia inoculation and increased plant N accumulation by 12%. In oculation with UW85 also increased whole-plant nodulation (nodules plant-1) by 16%, but there were no effects on specific nodulation [nodules g-1 root dry weight (DW)], individual nodule DW, nitrogenase activity (μmol H2 g-1 nodule DW h-1) or N2 fixation efficiency (g plant-N g-1 nodule DW). Inoculation of pea with UW85 at the low temperature regime increased whole-plant nodulation by 19%, but had no positive effects on any other growth parameters. Inoculation of common bean with UW85 had no positive effects on any aspects of growth, nodulation or nitrogenase activity. Our data indicate that under gnotobiotic conditions, UW85 inoculation increases nodulation in soybean indirectly by increasing root growth and not stimulating the nodulation process per se. The bacterium had little to no positive effects on pea and common bean symbioses. Key words: Bacillus cereus UW85, Glycine max, growth-promotion, nodulation, Phaseolus vulgaris, Pisum sativum

scholarly journals THE EFFICIENCy OF DIFFERENT MEANS OF SOyBEAN INOCULATION wITH NODULE BACTERIA

2010 ◽  
Vol 10 ◽  
pp. 20-28
Author(s):  
S.M. Malichenko ◽  
V.K. Datsenko ◽  
P.M. Mamenko ◽  
S.Ya. Kots
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Nitrogenase Activity ◽  
Soybean Seeds ◽  
Nodule Bacteria ◽  
Standard Strain ◽  
Bacterial Cultures ◽  
Tn5 Mutants ◽  
Soybean Plants ◽  
Production Strain

The efficiency of the presowing soybean inoculation with nodule bacteria at direct seeds bacterization or introduction of inoculum to the soil at presowing cultivation as well as the ability of rhizobia remained in the soil to the next year to form active symbioses with soybean plants was studied. The liquid bacterial cultures of production strain Bradyrhizobium japonicum 634b and three perspective Tn5-mutants of B. japonicum 646 were used. The introduction of the inoculum to soil was shown to be more efficient during both years of investigations as compared with the seeds inoculation which resulted in higher number of nodules formed, their nitrogenase activity and greater soybean seeds yield. Two of three studied Tn5-mutants had surpassed the standard strain by the efficiency indices.

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