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).

Acid tolerance in legume root nodule bacteria and selecting for it

2001 ◽  
Vol 41 (3) ◽  
pp. 435 ◽  
Author(s):  
M. J. Dilworth ◽  
J. G. Howieson ◽  
W. G. Reeve ◽  
R. P. Tiwari ◽  
A. R. Glenn
Keyword(s):  
Root Nodule ◽  
Acid Soils ◽  
Acid Tolerance ◽  
Interactive Effects ◽  
Regulator Gene ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Acid Ph ◽  
Wide Range ◽  
Concentration Changes

Bacteria face a variety of problems in trying to survive and grow in acidic environments. These include maintaining intracellular pH (pHi) in order to protect internal cell components, modifying or abandoning those external structures inevitably exposed to acidity, and resisting stresses whose interaction with pH may be the actual determinant of survival or growth rather than H+ toxicity per se. An important aspect of acid resistance in Gram-negative bacteria (including the root nodule bacteria) is the adaptive acid tolerance response (ATR), whereby cells grown at moderately acid pH are much more resistant to being killed under strongly acidic conditions than are cells grown at neutral pH. Survival during pH shock is also markedly affected by the calcium concentration in the medium. The pH at which commercial legume inoculants are grown and supplied for inoculation into acid soils may therefore be of considerable importance for initial inoculant survival. The mechanisms of resistance to acidity in root nodule bacteria have been investigated via 3 approaches: (i) creation of acid-sensitive mutants from acid-tolerant strains, and identification of the genes involved; (ii) random insertion of reporter genes to create mutants with pH-dependent reporter expression; and (iii) proteomics and identification of proteins regulated in response to acidity. The results of the first approach, directed at genes essential for growth at acid pH, have identified a sensor–regulator gene pair (actS–actR), a copper-transporting ATPase (actP), and another gene involved in lipid metabolism (actA), inactivation of which results in sensitivity to heavy metals. While the ActS–ActR system is undoubtedly required for both acid tolerance and the ATR, it is also involved in global regulation of a wide range of cellular processes. The second approach has allowed identification of a range of acid-responsive genes, which are not themselves critical to growth at low pH. One of these (phrR) is itself a regulator gene induced by a range of stresses including acid pH, but not controlled by the ActS–ActR system. Another, lpiA, responds specifically to acidity (not to other stresses) and may well be an antiporter related to nhaB, which is involved in Na+ transport in other bacteria. The third approach indicates a number of proteins whose concentration changes with a switch from neutral to acidic growth pH; most of these seem to have no homologues in the protein databases, while the blocked N-terminal sequences of others have prevented identification. It has been common experience that strains of root nodule bacteria selected for acid tolerance in the laboratory are not necessarily successful as inoculants in acid soils. In the light of the complex interactive effects on growth and survival of H+, Ca2+ and Cu2+ concentrations in our studies, this lack of correlation is no longer surprising. It remains to be seen whether it will be possible to improve the correlation between growth on laboratory media and performance in acid soils by determining which strains show an ATR, and by screening on media with defined ranges of concentration of some of these critical metal ions, perhaps approximating those to be expected in the soils in question.

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.

scholarly journals Use of Potato Extract Broth for Culturing Root-Nodule Bacteria

2011 ◽  
Vol 60 (4) ◽  
pp. 323-327 ◽  
Author(s):  
STEFAN MARTYNIUK ◽  
JADWIGA OROŃ
Keyword(s):  
Host Plants ◽  
Root Nodule ◽  
Nodule Bacteria ◽  
Liquid Media ◽  
Standard Medium ◽  
Root Nodule Bacteria ◽  
Beneficial Effects ◽  
Viable Cells ◽  
Yeast Extract Mannitol ◽  
Potato Extract

Liquid media containing potato extract and 1% of glucose or sucrose were used to culture root-nodule bacteria (rhizobia) in shaken Erlenmeyer flasks. For comparison, these bacteria were also cultured in yeast extract-mannitol broth (YEMB) as a standard medium. Proliferation of rhizobia was monitored by measuring optical densities (OD550) of the cultures and by plate counting of the viable cells (c.f.u) of the bacteria. In general, multiplication of the rhizobia in potato extract-glucose broth (PEGB) and potato extract-sucrose broth (PESB) was markedly faster, as indicated by higher values of OD550, than in YEMB. The numbers of R. leguminosarum by. vicae GGL and S. meliloti 330 in PEGB and PEGB were high and ranged from 1.2 x 10(10) to 4.9 x 10(10) mL(-1) after 48 h of incubation at 28 degrees C. B. japonicum B3S culture in PEGB contained 6.4 x 10(9) c.f.u. ml(-1) after 72 h of incubation. PEGB and YEMB cultures of the rhizobia were similar with respect to their beneficial effects on nodulation of the host-plants of these bacteria.

Evolutionary Geography of Root Nodule Bacteria: Speciation Directed by the Host Plants

Microbiology ◽  
2020 ◽  
Vol 89 (1) ◽  
pp. 1-12
Author(s):  
N. A. Provorov ◽  
E. E. Andronov ◽  
A. K. Kimeklis ◽  
E. R. Chirak ◽  
E. S. Karasev ◽  
...  
Keyword(s):  
Host Plants ◽  
Root Nodule ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria

scholarly journals Rhizobium loti, a New Species of Legume Root Nodule Bacteria

1982 ◽  
Vol 32 (3) ◽  
pp. 378-380 ◽  
Author(s):  
B. D. W. JARVIS ◽  
C. E. PANKHURST ◽  
J. J. PATEL
Keyword(s):  
New Species ◽  
Root Nodule ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Rhizobium Loti ◽  
A New Species

The Colonial Documentary Film in South and South-East Asia

2017 ◽  
Keyword(s):  
East Asia ◽  
Subject Matter ◽  
Documentary Film ◽  
East Asian ◽  
South East Asia ◽  
Post Colonial ◽  
Historical Perspectives ◽  
The Third ◽  
Wide Range ◽  
Global Understanding

Writing from a wide range of historical perspectives, contributors to the anthology shed new light on historical, theoretical and empirical issues pertaining to the documentary film, in order to better comprehend the significant transformations of the form in colonial, late colonial and immediate post-colonial and postcolonial times in South and South-East Asia. In doing so, this anthology addresses an important gap in the global understanding of documentary discourses, practices, uses and styles. Based upon in-depth essays written by international authorities in the field and cutting-edge doctoral projects, this anthology is the first to encompass different periods, national contexts, subject matter and style in order to address important and also relatively little-known issues in colonial documentary film in the South and South-East Asian regions. This anthology is divided into three main thematic sections, each of which crosses national or geographical boundaries. The first section addresses issues of colonialism, late colonialism and independence. The second section looks at the use of the documentary film by missionaries and Christian evangelists, whilst the third explores the relation between documentary film, nationalism and representation.

Duoethnography: A Polytheoretical Approach to (Re)Storing, (Re)Storying the Meanings That One Gives

2020 ◽  
pp. 396-423
Author(s):  
John Joseph Norris ◽  
Richard D. Sawyer
Keyword(s):  
Social Justice ◽  
Critical Theory ◽  
Third Space ◽  
The Third ◽  
The Core ◽  
Wide Range ◽  
Core Elements ◽  
Feminist Inquiry

This chapter summarizes the advancement of duoethnography throughout its fifteen-year history, employing examples from a variety of topics in education and social justice to provide a wide range of approaches that one may take when conducting a duoethnography. A checklist articulates what its cofounders consider the core elements of duoethnographies, additional features that may or may not be employed and how some studies purporting to be duoethnographies may not be so. The chapter indicates connections between duoethnography and a number of methodological concepts including the third space, the problematics of representation, feminist inquiry, and critical theory using published examples by several duoethnographers.

scholarly journals The Coevolution of Plants and Microbes Underpins Sustainable Agriculture

2021 ◽  
Vol 9 (5) ◽  
pp. 1036
Author(s):  
Dongmei Lyu ◽  
Levini A. Msimbira ◽  
Mahtab Nazari ◽  
Mohammed Antar ◽  
Antoine Pagé ◽  
...  
Keyword(s):  
Microbial Community ◽  
Plant Growth ◽  
Stress Resistance ◽  
Mycorrhizal Fungi ◽  
Plant Tissues ◽  
Terrestrial Plants ◽  
Plant Host ◽  
Symbiotic Relationships ◽  
Wide Range ◽  
Terrestrial Environments

Terrestrial plants evolution occurred in the presence of microbes, the phytomicrobiome. The rhizosphere microbial community is the most abundant and diverse subset of the phytomicrobiome and can include both beneficial and parasitic/pathogenic microbes. Prokaryotes of the phytomicrobiome have evolved relationships with plants that range from non-dependent interactions to dependent endosymbionts. The most extreme endosymbiotic examples are the chloroplasts and mitochondria, which have become organelles and integral parts of the plant, leading to some similarity in DNA sequence between plant tissues and cyanobacteria, the prokaryotic symbiont of ancestral plants. Microbes were associated with the precursors of land plants, green algae, and helped algae transition from aquatic to terrestrial environments. In the terrestrial setting the phytomicrobiome contributes to plant growth and development by (1) establishing symbiotic relationships between plant growth-promoting microbes, including rhizobacteria and mycorrhizal fungi, (2) conferring biotic stress resistance by producing antibiotic compounds, and (3) secreting microbe-to-plant signal compounds, such as phytohormones or their analogues, that regulate aspects of plant physiology, including stress resistance. As plants have evolved, they recruited microbes to assist in the adaptation to available growing environments. Microbes serve themselves by promoting plant growth, which in turn provides microbes with nutrition (root exudates, a source of reduced carbon) and a desirable habitat (the rhizosphere or within plant tissues). The outcome of this coevolution is the diverse and metabolically rich microbial community that now exists in the rhizosphere of terrestrial plants. The holobiont, the unit made up of the phytomicrobiome and the plant host, results from this wide range of coevolved relationships. We are just beginning to appreciate the many ways in which this complex and subtle coevolution acts in agricultural systems.

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