scholarly journals Biological nitrogen fixation by two Acacia species and associated root-nodule bacteria in a suburban Australian forest subjected to prescribed burning

2019 ◽  
Vol 20 (1) ◽  
pp. 122-132 ◽  
Author(s):  
Frédérique Reverchon ◽  
Kadum M. Abdullah ◽  
Shahla Hosseini Bai ◽  
Emanuel Villafán ◽  
Timothy J. Blumfield ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Root Nodule ◽  
Prescribed Burning ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Acacia Species ◽  
Biological Nitrogen

Biological Nitrogen Fixation and Root-Nodule Bacteria (Rhizobium Sp. and Bradyrhizobium Sp.) In Two Rehabilitating Sand Dune Areas Planted With Acacia Spp

1985 ◽  
Vol 33 (5) ◽  
pp. 595 ◽  
Author(s):  
YM Barnet ◽  
PC Catt ◽  
DH Hearne
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Sand Dune ◽  
Root Nodule ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Bradyrhizobium Sp ◽  
Biological Nitrogen ◽  
Slow Growing ◽  
Rhizobium Sp

This paper reports a study of biological nitrogen fixation in two sand dune regions of New South Wales where planted Acacia spp. had been used in revegetation programmes. At one location (Bridge Hill Ridge), natural regrowth had produced a complex plant community, and native legumes in addition to the planted acacias were present. The other area (Wanda Beach) was a grossly disturbed site which contained only the planted species. Symbiotic fixation in association with Australian legumes occurred at both locations at rates within the range reported by other authors. Distinct seasonal changes were apparent, with higher activities in the cooler months. The legume association seemed the only source of biologically fixed nitrogen at Bridge Hill Ridge, but at Wanda Beach cyanobacteria in an algal mat also made a contribution. Fast and slow-growing bacterial strains were obtained from root nodules of native legumes at both sites and were classed as Rhizobium sp. and Bradyrhizobium sp., respectively. This division was supported by the pattern of serological affinities of the isolates and by differences in their protein profiles demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two atypical types of root-nodule bacteria were found at Bridge Hill Ridge: non-nodulating, fast-growing isolates and an abnormally slow-growing Bradyrhizobium sp.

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.

scholarly journals Isolation and Enumeration of Bradyrhizobium Species Dwelling In the Root Nodules of Soybean Plant

2020 ◽  
pp. 17-25
Author(s):  
Ishaq Z. ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Root Nodule ◽  
Low Cost ◽  
Root Nodules ◽  
Selective Medium ◽  
Soybean Plant ◽  
Plant Infection ◽  
Soybean Plants ◽  
Biological Nitrogen

Biological Nitrogen fixation is one of the important aspects of organic agriculture gaining considerable attention globally. Information about the number of viable indigenous Bradyrhizobia in soils planted with legumes and their capacity to nodulate is a valuable tool in developing strategies to improve biological nitrogen fixation. Such strategies could potentially lead to increased soybean yields at low cost. This study was conducted to isolate and enumerate Bradyrizobium species dwelling in the root nodule of soybean plant using Bradyrhizobium japonicum selective medium (BJSM). Twenty (20) strains of Bradyrizobium species were isolated from the root nodules of soybean plants harvested from Ahmadu Bello University farm site, located at Bomo district of Sabongari local government area, Kaduna State, Nigeria. This was achieved using the streak method of isolation on BJSM. Ninety percent (18) of these isolates were confirmed as Bradyrizobium species using the plant infection test as they were able to nodulate the roots of soybean plants. The enumeration of the indigenous Bradyrizobium species gave a count ranging from 2.07x105 - 4.0x106 CFU/mL. Thus, the number of Bradyrhizobia obtained in the soil of this study is sufficient to achieve satisfactory results on nodulation and nitrogen fixation. Key words: Soybean, Bradyrhizobium species, Nodulation, Nitrogen fixation

scholarly journals Screening of Rhizobium, Hairy Vetch Root Nodule Bacteria, with Promotion of Nodulation and Nitrogen Fixation

2013 ◽  
Vol 49 (2) ◽  
pp. 131-136
Author(s):  
Jong-Ok Jang ◽  
Mi-Kyung Kwon ◽  
Dong-Jin Park ◽  
Chang Keun Sung ◽  
Chang-Jin Kim
Keyword(s):  
Nitrogen Fixation ◽  
Root Nodule ◽  
Nodule Bacteria ◽  
Hairy Vetch ◽  
Root Nodule Bacteria

scholarly journals Legume root nodule symbiosis: An evolving story in biology and biotechnology

2013 ◽  
Vol 35 (4) ◽  
pp. 14-18 ◽  
Author(s):  
Nicholas J. Brewin
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Root Nodule ◽  
Root Nodule Symbiosis ◽  
Evolution Of Life ◽  
Living Organisms ◽  
Life On Earth ◽  
Biological Nitrogen ◽  
Global Nitrogen Cycle ◽  
Nodule Symbiosis

The evolution of biological nitrogen fixation is central to the evolution of life on earth. Nitrogen is an essential component of proteins and nucleic acids and its restricted availability to living organisms has often been a major factor limiting growth. Despite the overwhelming abundance of N2 gas in the atmosphere, di-nitrogen is chemically inaccessible to most forms of life. For their growth and metabolism, most organisms use the ‘fixed’ forms of nitrogen, either as ammonium (NH4+) or as nitrate (NO3-), or derivatives thereof. However, the major input into the global nitrogen cycle is through the reductive process of biological nitrogen fixation which converts atmospheric N2 into ammonia (NH3). This process evolved in bacteria and/or archaea over 2.5 billion years ago while the planet still had a reducing atmosphere. Today, biological nitrogen fixation is still restricted to the bacteria and archaea. The legume root nodule symbiosis allows the host plant to benefit directly by association with soil bacteria, collectively termed rhizobia, which fix nitrogen as endosymbionts.

Nutritional constraints on root nodule bacteria affecting symbiotic nitrogen fixation: a review

2001 ◽  
Vol 41 (3) ◽  
pp. 417 ◽  
Author(s):  
G. W. O'Hara
Keyword(s):  
Nitrogen Fixation ◽  
Root Nodule ◽  
Nutrient Deficiency ◽  
Nodule Development ◽  
Nutrient Deficiencies ◽  
Nodule Bacteria ◽  
Free Living ◽  
Root Nodule Bacteria ◽  
Molecular Approaches ◽  
Calcium Iron

Root nodule bacteria require access to adequate concentrations of mineral nutrients for metabolic processes to enable their survival and growth as free-living soil saprophytes, and in their symbiotic relationship with legumes. Essential nutrients, with a direct requirement in metabolism of rhizobia are carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, potassium, calcium, magnesium, iron, manganese, copper, zinc, molybdenum, nickel, cobalt and selenium. Boron does not seem to be required by rhizobia, but is essential for the establishment of effective legume symbioses. Nutrient constraints can affect both free-living and symbiotic forms of root nodule bacteria, but whether they do is a function of a complex series of events and interactions. Important physiological characteristics of rhizobia involved in, or affected by, their mineral nutrition include nutrient uptake, growth rate, gene regulation, nutrient storage, survival, genetic exchange and the viable non-culturable state. There is considerable variation between genera, species and strains of rhizobia in their response to nutrient deficiency. The effects of nutrient deficiencies on free-living rhizobia in the soil are poorly understood. Competition between strains of rhizobia for limiting phosphorus and iron in the rhizosphere may affect their ability to nodulate legumes. Processes in the development of some legume symbioses specifically require calcium, cobalt, copper, iron, potassium, molybdenum, nickel, phosphorus, selenium, zinc and boron. Limitations of phosphorus, calcium, iron and molybdenum in particular, can reduce legume productivity by affecting nodule development and function. The effects of nutrient deficiencies on rhizobia–legume signalling are not understood. The supply of essential inorganic nutrients to bacteroids in relation to nutrient partitioning in nodule tissues and nutrient transport to the symbiosome may affect effectiveness of nitrogen fixation. An integration of molecular approaches with more traditional biochemical, physiological and field-based studies is needed to improve understanding of the agricultural importance of rhizobia response to nutrient stress.

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