Genetics of symbiosis and nitrogen fixation in legumes

1969 ◽  
Vol 172 (1029) ◽  
pp. 417-437 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Bacterial Strain ◽  
Host Plants ◽  
Strain Differences ◽  
Homogeneous Material ◽  
Developmental Sequence ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Microbial Genetics ◽  
Nodular Tissue

Soon after the isolation of nodule bacteria in 1888, differences were recognized in the ability of bacterial strains to form nodules on particular host plants and in the nitrogen-fixing ability of the nodules so formed. These and other symbiotic heterogeneities were attributed, sometimes correctly, to bacterial strain differences, not then thought to be open to formal genetic analysis. The realization that the host plant was an essential component of this variability came only gradually, stimulated by observations of host varietal differences and by the demand for reliable and homogeneous material for experimental work. Only within the last two decades has host variability been studied by plant breeding, and bacterial strain differences by some of the methods of microbial genetics. This review, except for a brief reference to earlier work of some historic interest, will consider only genetic problems open to investigation by these methods. The developmental sequence in all legume nodules is broadly similar. The initial infection phases are followed by the induction of the nodule, the invasion of part of the nodular tissue and culminate in bacteroid formation and nitrogen fixation; the genetics of symbiosis will be considered in this context.

scholarly journals The growth of nodule bacteria in the expressed juices from legume roots bearing effective and ineffective nodules

1940 ◽  
Vol 129 (857) ◽  
pp. 475-491 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Host Plants ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Nodule Growth ◽  
Different Strains

Strains of pea and soy-bean nodule bacteria, differing in their effectiveness in benefiting the host legume, were grown in media containing the unheated root juices from uninoculated host plants and from host plants bearing effective and 'ineffective' nodules, and their growth was measured. The growth of the different bacterial strains on root juice from uninoculated plants was not correlated with their effectiveness. The juice from roots with effective nodules produced significantly better growth of the bacteria than juice from roots with ineffective nodules in twenty-seven comparisons out of forty-four, the differences in the remaining comparisons being insignificant. The juice from roots with effective nodules produced significantly better growth than the juice from uninoculated roots in ten comparisons out of twenty-five, and significantly poorer growth in three comparisons. The juice from roots with ineffective nodules produced significantly poorer growth than the juice from uninoculated plants in eleven comparisons out of twenty-five, and better growth in only one comparison. The production, as a result of infection, of soluble substances affecting growth of the bacteria, affords an explanation of those differences in nodule growth that determine the effectiveness or ineffectiveness of the different strains of bacteria as regards nitrogen fixation within the host.

A STUDY OF THE DISTRIBUTION AND THE EFFECTS OF BACTERIOPHAGE OF ROOT NODULE BACTERIA IN THE SOIL

1957 ◽  
Vol 3 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Janina Kleczkowska
Keyword(s):  
Nitrogen Fixation ◽  
Root Nodule ◽  
Surrounding Medium ◽  
Antigenic Structure ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Bacterial Mutants ◽  
Resistant Mutants ◽  
Bacterial Mixtures

Bacteriophage for clover nodule bacteria can be found on roots and nodules of all naturally grown clover plants and also in the soil surrounding the roots, but not in soil without clover plants. Alternative hosts for the phage of clover bacteria are pea bacteria, and vice versa. The bacteria and the phage are heterogeneous in the sense that only a proportion of strains of clover bacteria and of pea bacteria are susceptible to lysis by a given race of phage, and only a proportion of races of phage can lyse a given bacterial strain. There does not seem to be any association between the susceptibility of bacterial strains to lysis by phage and any other features such as antigenic structure and effectiveness in nitrogen fixation. There may be an association with avirulence, i.e. inability to infect the host plant. The behavior of phage–bacterial mixtures depends on the surrounding medium. The longevity of phage in soil or in a soil-like medium such as a vermiculite mixture is relatively short, and the effect of phage can be localized so that phage-susceptible bacteria and the phage can exist close to each other without any apparent interaction. However, as long as the phage is present, phage-resistant bacterial mutants are usually present also. The phage-resistant mutants may also be mutants in other respects such as effectiveness in nitrogen fixation. In the presence of weakened phage, bacterial mutants were found to occur that differ from the parent form in effectiveness but resemble it in susceptibility to the phage.

Regularities of the genotype’s distribution of phylogenetically homogenous bacteria Rhizobium leguminosarum in the nodules of separate populations of Lathyrus vernus (spring pea) plants

Biomics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 100-105
Author(s):  
An. Baymiev ◽  
O. Lastochkina ◽  
I. Koryakov ◽  
E. Akimova ◽  
A. Vladimirova ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Information ◽  
Host Plants ◽  
Rhizobium Leguminosarum ◽  
Genetic Differences ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Ongoing Process ◽  
Rhizobium Strains ◽  
Lathyrus Vernus

The genotypes of phylogenetically homogeneous Rhizobium leguminosarum bacterial strains in nodules of Lathyrus vernus plants were studied. The degree of genetic variation between bacteria within nodules of one L. vernus population correlated with the distance between host plants: the greater the distance, the greater the genetic differences between their microsymbionts. This may be due to the ongoing process of exchanging genetic information between Rhizobium strains, with the depends on the distance between them. But in some cases, this pattern was not observed, and there were significant differences between the microsymbionts of neighboring plants. Most likely, with the exception of spatial limitations, there are some other barriers that exist to the free exchange of genetic information between nodule bacteria.

scholarly journals Effect of TiO2 on Selected Pathogenic and Opportunistic Intestinal Bacteria

2021 ◽  
Author(s):  
Ewa Baranowska-Wójcik ◽  
Dominik Szwajgier ◽  
Klaudia Gustaw
Keyword(s):  
Titanium Dioxide ◽  
Bacterial Strain ◽  
Intestinal Bacteria ◽  
Food Additive ◽  
Bacterial Strains ◽  
Gastrointestinal Microbiota ◽  
Food Grade ◽  
The Eu

AbstractFood-grade titanium dioxide (TiO2) containing a nanoparticle fraction (TiO2 NPs-nanoparticles) is widely used as a food additive (E171 in the EU). In recent years, questions concerning its effect on the gastrointestinal microbiota have been raised. In the present study, we examined interactions between bacteria and TiO2. The study involved six pathogenic/opportunistic bacterial strains and four different-sized TiO2 types: three types of food-grade E171 compounds and TiO2 NPs (21 nm). Each bacterial strain was exposed to four concentrations of TiO2 (60, 150, 300, and 600 mg/L TiO2). The differences in the growth of the analyzed strains, caused by the type and concentration of TiO2, were observed. The growth of a majority of the strains was shown to be inhibited after exposure to 300 and 600 mg/L of the food-grade E171 and TiO2 NPs.

Nodulation studies on legumes exotic to Australia: symbiotic relationships between Chamaecytisus palmensis (tagasaste) and Lotus spp

1994 ◽  
Vol 34 (3) ◽  
pp. 385 ◽  
Author(s):  
RR Gault ◽  
A Pilka ◽  
DM Hebb ◽  
J Brockwell
Keyword(s):  
Host Plants ◽  
Root Nodule ◽  
Pattern Analysis ◽  
Analysis Procedure ◽  
Nodule Bacteria ◽  
Symbiotic Relationships ◽  
The Third ◽  
Rhizobium Loti ◽  
Wide Range ◽  
Bradyrhizobium Sp

Strains of rhizobia were isolated from soil around the roots of tagasaste (Chamaecytisus palmensis) growing at 15 widely separated locations in south-eastem Australia. A further collection of strains of both Rhizobium loti and Bradyrhizobium sp. (Lotus) was assembled from 18 legumes including Lotus and other species symbiotically related to Lotus. The strains were used to inoculate tagasaste and 4 species of Lotus in experiments conducted under bacteriologically controlled conditions in a temperature-controlled glasshouse. Tagasaste formed nodules and fixed N2 with all of its homologous rhizobia but there was a wide range of effectiveness among the 15 strains. Tagasaste also formed nodules with each of the 18 strains from other species but fixed N2 with only 10. Four species of Lotus were inoculated with 3 tagasaste strains. One strain nodulated each species and fixed N2 with L. conimhricensis and L. corniculatus but not with L. parviflorus or L. pedunculatus. A second tagasaste strain formed nodules with all 4 Lotus spp. but did not fix N2, while the third nodulated only L. pedunculatus but did not fix N2. A pattern analysis based on the nodulating ability of the host plants in association with 21 strains showed that tagasaste and L. corniculatus formed 1 symbiotic group, and the other 3 Lotus species formed a third group. The pattern analysis procedure based on nodulating capacity of 21 rhizobial strains in association with the 5 host species indicated substantial symbiotic diversity within the collection, with the strains comprising 8 different symbiotic groups. No strain was highly effective on both tagasaste and any of the 4 species of Lotus. Data were insufficient to classify the root-nodule bacteria of tagasaste as either Rhizobium loti or Bradyrhizobium sp. (Lotus).

scholarly journals Appraising Endophyte–Plant Symbiosis for Improved Growth, Nodulation, Nitrogen Fixation and Abiotic Stress Tolerance: An Experimental Investigation with Chickpea (Cicer arietinum L.)

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 621 ◽  
Author(s):  
Ahmad ◽  
Naseer ◽  
Hussain ◽  
Zahid Mumtaz ◽  
Mustafa ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Root Nodules ◽  
Abiotic Stress Tolerance ◽  
Paenibacillus Polymyxa ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Pgp Traits ◽  
Paenibacillus Sp

Chickpea is an important leguminous crop that improves soil fertility through atmospheric nitrogen fixation with the help of rhizobia present in nodules. Non-rhizobia endophytes are also capable of inducing nodulation and nitrogen fixation in leguminous crops. The aim of the current study was to isolate, characterize and identify the non-rhizobia endophytic bacterial strains from root nodules of chickpea. For this purpose, more than one hundred isolates were isolated from chickpea root nodules under aseptic conditions and were confirmed as endophytes through re-isolating them from root nodules of chickpea after their inoculation. Nineteen confirmed endophytic bacterial strains revealed significant production of indole acetic acid (IAA) both in presence and absence of L-tryptophan and showed their ability to grow under salt, pH and heavy metal stresses. These strains were evaluated for in vitro plant growth promoting (PGP) traits and results revealed that seven strains showed solubilization of P and colloidal chitin along with possessing catalase, oxidase, urease and chitinase activities. Seven P-solubilizing strains were further evaluated in a jar trial to explore their potential for promoting plant growth and induction of nodulation in chickpea roots. Two endophytic strains identified as Paenibacillus polymyxa ANM59 and Paenibacillus sp. ANM76 through partial sequencing of the 16S rRNA gene showed the maximum potential during in vitro PGP activities and improved plant growth and nodulation in chickpea under the jar trial. Use of these endophytic strains as a potential biofertilizer can help to reduce the dependence on chemical fertilizers while improving crop growth and soil health simultaneously.

scholarly journals Optimizing the Management of Cadmium Bioremediation Capacity of Metal-Resistant Pseudomonas sp. Strain Al-Dhabi-126 Isolated from the Industrial City of Saudi Arabian Environment

2019 ◽  
Vol 16 (23) ◽  
pp. 4788 ◽  
Author(s):  
Naif Abdullah Al-Dhabi ◽  
Galal Ali Esmail ◽  
Abdul-Kareem Mohammed Ghilan ◽  
Mariadhas Valan Arasu
Keyword(s):  
Bacterial Strain ◽  
Cadmium Toxicity ◽  
Industrial Effluents ◽  
Pseudomonas Sp ◽  
Bacterial Strains ◽  
16S Rdna Gene ◽  
Sequence Characterization ◽  
Industrial City ◽  
Toxic Pollutant ◽  
Cd Removal

In this study, 23 bacterial strains were isolated from a Cadmium (Cd) contaminated soil in the industrial city, Riyadh of Saudi Arabia. Among these isolates six strains were found to withstand cadmium contamination and grow well. From the six isolates Pseudomonas sp. strain Al-Dhabi-122–127 were found to resist cadmium toxicity to a higher level. The isolates were subjected to biochemical and 16S rDNA gene sequence characterization to confirm their identification. The bacterial strain Al-Dhabi-124 showed 1.5 times higher Cd-degrading activity than Al-Dhabi-122 and Al-Dhabi-123, and Al-Dhabi-126 exhibited 3.5 times higher Cd-degrading activity, higher than the other strains. An atomic absorption spectrophotometer study showed that the strain Al-Dhabi-126 absorbed Cd, and that the bacterial strain Al-Dhabi-126 was found to tolerate cadmium level up to 2100 µg/mL. The bacterial strain Al-Dhabi-126 showed a maximum Cd removal efficacy at pH between 6.0 and 8.0. The efficacy decreased sharply after an increase in pH (9.0). An optimum temperature of 50 °C and pH 6.0 were found to be effective for the Cd removal process by the isolate. The study indicated that the bacterial strain Al-Dhabi-126 can be used effectively for the bioremediation of heavy metals like cadmium, a major toxic pollutant in industrial effluents.

scholarly journals Assessing the Use of Wing Morphometrics to Identify Fall Armyworm (Lepidoptera: Noctuidae) Host Strains in Field Collections

2019 ◽  
Vol 113 (2) ◽  
pp. 800-807
Author(s):  
Kira L Nagoshi ◽  
Sandra A Allan ◽  
Robert L Meagher
Keyword(s):  
Host Plants ◽  
Strain Differences ◽  
Fall Armyworm ◽  
Growth Patterns ◽  
Western Hemisphere ◽  
Anatomical Landmarks ◽  
Wing Morphology ◽  
Linear Discriminant ◽  
Lepidoptera Noctuidae ◽  
Host Strains

Abstract The fall armyworm (Spodoptera frugiperda) (J. E. Smith) (Lepidoptera: Noctuidae), a major agricultural pest in the Western Hemisphere, has recently become established in Africa and Asia. This highly polyphagous species has potential to economically harm multiple crops. Contributing to this host range are two fall armyworm populations historically called ‘host strains’ that differ in host specificity. Understanding behaviors of the two strains is crucial to effective management of this pest. A major difficulty in such studies is that strains have long been considered morphologically indistinguishable, with molecular markers the only reliable means of identification. However, studies of fall armyworm in Colombia reported strain differences in wing morphology sufficiently large to potentially provide a more economical alternative method to determine strain. This study tested whether a similar phenotypic difference was present in Florida populations using geometric morphometric analysis of 15 anatomical landmarks on forewings of 182 specimens from three habitats associated with different host plants. Principle component and linear discriminant analyses identified significant differences in wing size and shape in comparison of strains from different habitats, but not between strains within the same habitat. Data indicate that apparent strain distinctions in wing phenotype are most likely a secondary consequence of differences in developmental growth patterns on different host plants combined with strain-biased host choice. Furthermore, Florida specimens showed much larger phenotypic overlap than observed for strains from Colombia. Together these findings suggest that wing morphology is probably not a reliable indicator of strain identity in field populations where different host plants are available.

scholarly journals Opposite Enantioselectivities of Two Phenotypically and Genotypically Similar Strains of Pseudomonas frederiksbergensis in Bacterial Whole-Cell Sulfoxidation

2005 ◽  
Vol 71 (4) ◽  
pp. 2199-2202 ◽  
Author(s):  
Waldemar Adam ◽  
Frank Heckel ◽  
Chantu R. Saha-Möller ◽  
Marcus Taupp ◽  
Jean-Marie Meyer ◽  
...  
Keyword(s):  
Bacterial Strain ◽  
Genetically Modified Organisms ◽  
Genetically Modified ◽  
Soil Samples ◽  
Bacterial Strains ◽  
Whole Cell ◽  
Organic Sulfides

ABSTRACT Soil samples were screened to select microorganisms with the capability to oxidize organic sulfides into the corresponding sulfoxides with differential enantioselectivities. Several bacterial strains that preferentially produced the S-configured sulfoxide enantiomer were isolated. Surprisingly, one bacterial strain, genotypically and phenotypically characterized as Pseudomonas frederiksbergensis, selectively gave the R enantiomer. The finding that two apparently identical organisms displayed opposite enantioselectivities is novel for non-genetically modified organisms.

Investigations on the root nodule bacteria of leguminous plants: XIX. Influence of various factors on the excretion of nitrogenous compounds from the nodules

1937 ◽  
Vol 27 (3) ◽  
pp. 332-348 ◽  
Author(s):  
Artturi Ilmari Virtanen ◽  
Synnöve von Hausen ◽  
Tauno Laine
Keyword(s):  
Amino Acids ◽  
Nitrogen Fixation ◽  
Root Nodule ◽  
Nitrogen Nutrition ◽  
Nitrogen Compounds ◽  
Nodule Bacteria ◽  
Fixed Nitrogen ◽  
Nitrogenous Compounds ◽  
Primary Products ◽  
Equal Effectiveness

1. It has been shown experimentally that the excretion of nitrogen noted by us in cultures of inoculated legumes takes place from the nodule bacteria, probably from the intranodular ones, and not from the roots. No excretion of amino acids occurs in cultures of uninoculated legumes growing on nitrate nitrogen.2. Our earlier hypothesis that the legumes receive their nitrogen nutrition from the nodules in the form of organic nitrogen compounds, particularly amino acids, is in perfect accord with our new observations concerning the process of excretion. All facts indicate that the amino acids concerned are primary products of the nitrogen fixation, and not breakdown products of proteins. Bond's valuable work along quite different lines produced results which support this conclusion. He, however, did not study the chemical nature of the nitrogen compounds in question.3. The excretion of nitrogen occurs in media capable of absorbing the excreted nitrogen compounds (cellulose, kaolin, sand, soil). The demonstration of the excretion is not possible in water cultures except when very large quantities of water are used. On the basis of these facts a hypothesis is advanced to explain the nature of the excretion.4. The term total fixed nitrogen has been used as an expression for the extent of nitrogen fixation, while the term extent of excretion is employed to indicate that percentage of the total fixed nitrogen which is excreted from the nodules.5. The extent of excretion depends largely on the strain used for inoculation. With strains of apparently equal effectiveness in nitrogen fixation, the extent of excretion may vary considerably, so that actually such strains differ in their effectiveness.

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