scholarly journals Exogenous ACC Deaminase Is Key to Improving the Performance of Pasture Legume-Rhizobial Symbioses in the Presence of a High Manganese Concentration

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1630
Author(s):  
Ana Paço ◽  
José Rodrigo da-Silva ◽  
Denise Pereira Torres ◽  
Bernard R. Glick ◽  
Clarisse Brígido
Keyword(s):  
Rhizobium Leguminosarum ◽  
Subterranean Clover ◽  
Acc Deaminase ◽  
Trifolium Subterraneum ◽  
Endophytic Bacterium ◽  
Manganese Concentration ◽  
Soil Conditions ◽  
Knockout Mutant ◽  
Mn Toxicity ◽  
Pasture Legume

Manganese (Mn) toxicity is a very common soil stress around the world, which is responsible for low soil fertility. This manuscript evaluates the effect of the endophytic bacterium Pseudomonas sp. Q1 on different rhizobial-legume symbioses in the absence and presence of Mn toxicity. Three legume species, Cicer arietinum (chickpea), Trifolium subterraneum (subterranean clover), and Medicago polymorpha (burr medic) were used. To evaluate the role of 1-aminocyclopropane-1-carboxylate (ACC) deaminase produced by strain Q1 in these interactions, an ACC deaminase knockout mutant of this strain was constructed and used in those trials. The Q1 strain only promoted the symbiotic performance of Rhizobium leguminosarum bv. trifolii ATCC 14480T and Ensifer meliloti ATCC 9930T, leading to an increase of the growth of their hosts in both conditions. Notably, the acdS gene disruption of strain Q1 abolished the beneficial effect of this bacterium as well as causing this mutant strain to act deleteriously in those specific symbioses. This study suggests that the addition of non-rhizobia with functional ACC deaminase may be a strategy to improve the pasture legume–rhizobial symbioses, particularly when the use of rhizobial strains alone does not yield the expected results due to their difficulty in competing with native strains or in adapting to inhibitory soil conditions.

Response of subterranean clover, balansa clover, and gland clover to lime when grown in mixtures on an acid soil

2008 ◽  
Vol 59 (9) ◽  
pp. 824 ◽  
Author(s):  
R. C. Hayes ◽  
B. S. Dear ◽  
B. A. Orchard ◽  
M. B. Peoples ◽  
P. L. Eberbach
Keyword(s):  
Seed Yield ◽  
N2 Fixation ◽  
Acid Soil ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Soil Conditions ◽  
Pasture Production ◽  
Mn Toxicity ◽  
Annual Legumes

This study compared the relative tolerances of subterranean clover (Trifolium subterraneum L.), balansa clover (T. michelianum Savi.), and gland clover (T. glanduliferum Boiss.) to acid soil conditions. Seed yield, seedling density, herbage production, N2 fixation, and herbage mineral composition of the 3 legumes were assessed when grown on an acid soil (pHCa of 4.3 and 15% exchangeable Al [0–0.10 m]) with and without the addition of lime (CaCO3). Annual legume species were sown in a mixed sward together with burr medic (Medicago polymorpha L.), and in mixtures with either lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), or phalaris (Phalaris aquatica L.). Due to drier than average seasonal conditions, none of the perennial species persisted beyond the first summer. Lime increased the herbage production of annual legumes by 18–22% and total pasture production by 14% in both 2002 and 2003. Subterranean clover was the most tolerant of the annual legumes to acid soil conditions, showing no visible toxicity symptoms and no response to lime in terms of seed yield. In contrast, both balansa and gland clovers exhibited visual symptoms of manganese toxicity in the absence of lime, with Mn concentrations in the shoots of 817 mg/kg and 626 mg/kg, respectively. Both species responded positively to lime with seed yields increasing by 45% and 124%, respectively. Lime increased the proportion of herbage N derived from N2 fixation by subterranean clover from 29 to 40% and by gland clover from 30 to 43%. Lime had no effect on the proportion of N2 fixed by balansa clover (29–31%), suggesting a suboptimal symbiosis of rhizobia with that species. Adding chicory or phalaris to the pasture mix increased sward herbage production in the establishment year by 39% and 21%, respectively. Based on leaf symptoms and herbage yield responses to lime, Mn toxicity was present in lucerne with tissue levels of up to 916 mg/kg, but no symptoms were observed in chicory (1129 mg/kg) or phalaris (403 mg/kg). Chicory and phalaris were more tolerant of acidity and high levels of Mn than lucerne, gland clover, and balansa clover. The study highlighted the value of the small-seeded annual legumes, balansa clover and gland clover, to the production of mixed pasture swards even in drier than average seasonal conditions. Although more sensitive to acid soils than subterranean clover, they set a greater number of seeds and, in the case of balansa clover, a greater weight of seed under moisture stress in the establishment year than the larger seeded subterranean clover.

scholarly journals Harvesting subterranean clover seed – current practices, technology and issues

2021 ◽  
Vol 72 (3) ◽  
pp. 223
Author(s):  
Wesley M. Moss ◽  
Andrew L. Guzzomi ◽  
Kevin J. Foster ◽  
Megan H. Ryan ◽  
Phillip G. H. Nichols
Keyword(s):  
Soil Erosion ◽  
Case Studies ◽  
Seed Production ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Root Cause ◽  
Pasture Plant ◽  
Clover Seed ◽  
Production Industry ◽  
Pasture Legume

Subterranean clover (Trifolium subterraneum L.) is Australia’s most widely sown annual pasture legume. Its widespread use as a pasture plant requires a well-functioning seed production industry, and Australia is the only significant producer of subterranean clover seed globally. However, the sustainability of this industry is under threat due to its reliance on ageing harvest equipment and the resultant environmental impacts. In order to evaluate seed harvesting practices, technology, and issues, we report on case studies, workshops, and a survey of seed producers across southern Australia. The Horwood Bagshaw Clover Harvester, designed in the 1950s, remains the most popular subterranean clover seed harvester. We discuss its use and modifications, and document several contemporary issues facing the seed production industry. Issues are primarily soil erosion and degradation; the expensive, slow and labour-intensive harvest process; and poor reliability and maintainability of harvesters that are now at least 30 years old. We conclude the root cause of these issues is the suction harvest technology utilised by the Horwood Bagshaw Clover Harvester. Analysis of the current harvest system is provided to support the development of new approaches to harvest subterranean clover seeds.

Pasture legume species differ in their capacity to acidify soil

1998 ◽  
Vol 49 (1) ◽  
pp. 53 ◽  
Author(s):  
C. Tang ◽  
L. Barton ◽  
C. Raphael
Keyword(s):  
Acid Production ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growth Stages ◽  
Total Acid ◽  
Ash Alkalinity ◽  
Ornithopus Sativus ◽  
Excess Cations ◽  
Pasture Legume

The capacity of subterranean clover (Trifolium subterraneum L. cv. Clare), medic (Medicago murex Willd. cv. Zodiac), serradella (Ornithopus sativus Brot. line SP1/13), biserrula (Biserrula pelecinus L. line Mor99), and woolly clover (Trifolium tomentosum L.) to acidify soil under N2 fixation was compared in a pot experiment using a poorly buffered sandy soil. The amount of acid produced per kg shoot dry matter (specific acid production) varied betweefin species and with growth stages, ranging from 44 to 128 cmol/kg shoot. Subterranean clover and serradella acidied soil to a greater extent than woolly clover and medic, whereas biserrula acidified soil least. Irrespective of pasture species and growth stage, specific acid production correlated well with concentrations of excess cations and calcium in shoots. Furthermore, total excess cation, ash alkalinity, and calcium in shoots were all good indicators of total acid production across all of the species.

Erratum to: Two novel chromosomal loci influence cultivar-specific nodulation failure in the interaction between strain ANU794 and subterranean clover cv. Woogenellup

2002 ◽  
Vol 29 (7) ◽  
pp. 907
Author(s):  
Louise F. Roddam ◽  
Wendy R. Lewis-Henderson ◽  
Michael A. Djordjevic
Keyword(s):  
Rhizobium Leguminosarum ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Gene Interaction ◽  
Nodule Formation ◽  
Synthesis Inhibitor ◽  
Reading Frame ◽  
Ribosomal Protein L9 ◽  
Microbe Interactions ◽  
Cultivar Specificity

The nodulation failure resulting from the interaction between Rhizobium leguminosarum biovar trifolii strain ANU794 and the Trifolium subterraneum cv. Woogenellup was examined by transposon mutagenesis to resolve whether multiple determinants were involved in cultivar-specificity. Three new transposon-induced mutants of ANU794 (W72, W78 and W710) with significantly enhanced nodulation ability on cv. Woogenellup were identified. The W72 and W78 mutations are chromosomally-located, whereas the W710 mutation isplasmid-located. The ethylene synthesis inhibitor, aminoethoxyvinylglycine, fails to enhance the nodulation ability of ANU794, ANU7943 (csn1::Tn5) and W78 on cv. Woogenellup, but enhances the nodulation ability of W72,W710 and ANU7941 (nodM::Tn5). DNA sequencing of the W78 locus reveals strong homology to an unknown Mycobacterium open reading frame, and to several bacterial non-haem chloroperoxidases. The previously identified csn1 locus showed homology to the 50S ribosomal protein, L9, with the Tn5 insertion being located in the 5′-untranslated region. The results suggest that cultivar-specificity is mediated by at least two independent mechanisms or determinants, and not by a simple gene-for-gene interaction. The role of ethylene in cultivar specificity is discussed. Cultivar-specific interactions may prove useful in identifying pathways involved in efficient nodule formation and plant-microbe interactions.

Izmir subterranean clover (Trifolium subterraneum L. var. subterraneum)

2007 ◽  
Vol 47 (2) ◽  
pp. 226 ◽  
Author(s):  
P. G. H. Nichols ◽  
G. A. Sandral ◽  
B. S. Dear ◽  
C. T. de Koning ◽  
D. L. Lloyd ◽  
...  
Keyword(s):  
Seed Production ◽  
Seed Set ◽  
New South ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Good Seed ◽  
Improvement Program ◽  
South Wales ◽  
Pasture Legume

Izmir is a hardseeded, early flowering, subterranean clover of var. subterraneum (Katz. et Morley) Zohary and Heller collected from Turkey and developed by the collaborating organisations of the National Annual Pasture Legume Improvement Program. It is a more hardseeded replacement for Nungarin and best suited to well-drained, moderately acidic soils in areas with a growing season of less than 4.5 months. Izmir seed production and regeneration densities in 3-year pasture phases were similar to Nungarin in 21 trials across southern Australia, but markedly greater in years following a crop or no seed set. Over all measurements, Izmir produced 10% more winter herbage and 7% more spring herbage than Nungarin. Its greater hardseededness and good seed production, makes it better suited to cropping rotations than Nungarin. Softening of Izmir hard seeds occurs later in the summer–autumn period than Nungarin, giving it slightly greater protection from seed losses following false breaks to the season. Izmir is recommended for sowing in Western Australia, New South Wales, Victoria, South Australia and Queensland. Izmir has been granted Plant Breeders Rights in Australia.

Biserrula and subterranean clover can co-exist during the vegetative phase but are out-competed by capeweed

2011 ◽  
Vol 62 (3) ◽  
pp. 236 ◽  
Author(s):  
S. A. Conning ◽  
M. Renton ◽  
M. H. Ryan ◽  
P. G. H. Nichols
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Farming Systems ◽  
Exponential Model ◽  
Pasture Management ◽  
Relative Growth ◽  
Broad Leaf ◽  
Ley Farming ◽  
The Common ◽  
Pasture Legume

Biserrula (Biserrula pelecinus L.) is a recently domesticated annual pasture legume developed for ley farming systems that have traditionally relied upon subterranean clover (Trifolium subterraneum L.). This study examined competitive interactions between biserrula and subterranean clover and the common broad-leaf weed capeweed (Arctotheca calendula L.) during seedling establishment and vegetative growth, in order to develop guidelines for successful legume pasture management. Two glasshouse experiments were conducted to investigate the allocation of biomass to roots and shoots in biserrula, capeweed, and subterranean clover and its relationship with competitive ability in the first 100 days after sowing. In Experiment 1, capeweed had a higher relative growth rate of shoots and roots than the two legumes and developed a more extensive root system. Experiment 2 consisted of growing binary mixtures of the three species at different densities. The effect of competition on the biomass of biserrula, capeweed, and subterranean clover was best modelled by a power–exponential model. Increasing capeweed densities suppressed the biomass production of both biserrula and subterranean clover, whereas capeweed biomass increased with increasing densities of subterranean clover. This study suggests that the competitive advantage of capeweed is mainly conferred during the seedling stage. It also suggests that biserrula and subterranean clover germinating at the same time can co-exist as a mixed sward, at least up until flowering, if biserrula density is high relative to subterranean clover.

Persistence of introduced strains of Rhizobium leguminosarum bv trifolii in acidic soils of north-eastern Victoria

1999 ◽  
Vol 39 (7) ◽  
pp. 829 ◽  
Author(s):  
J. F. Slattery ◽  
D. R. Coventry
Keyword(s):  
Rhizobium Leguminosarum ◽  
Soil Amendments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Nodule Occupancy ◽  
Acidic Soils ◽  
High Background ◽  
Poor Tolerance ◽  
Acidic Sites ◽  
Commercial Inoculant

Summary. A 5-year study was undertaken to establish if introduced rhizobia with higher tolerance to Al than the current inoculant Rhizobium can persist and continue nodulating subterranean clover (Trifolium subterraneum L.) in acidic soils. Two Rhizobium leguminosarum bv trifolii strains were introduced as seed inoculants with subterranean clover at 2 acidic sites (pHCa 4.1 and pHCa 4.3), where lime and gypsum had been applied as soil amendments. Strain NA3001 was selected for its tolerance to high Al concentrations when grown on an agar medium and WU95, which is a widely used commercial inoculant strain, for its relatively poor tolerance to Al when grown on agar. Liming the soil increased its pH and reduced the concentration of extractable Al at both sites. In the year the subterranean clover was sown, strain WU95 had nodule occupancy of 20–49%, decreasing with time to 4–7% after 5 seasons (1991–95). The nodule occupancy of strain NA3001 was initially lower than strain WU95 (14–16%), but its occupancy did not vary with time (significant strain x time interactions, P<0.05). These data indicate that the acid-tolerant strain NA3001 has the potential to persist in these strongly acidic soils and, despite the presence of high background populations of naturalised rhizobia, to continue initiating nodulation. The use of soil amendments (lime and gypsum) to increase pH and reduce soluble Al concentrations did not affect the nodule occupancy of either NA3001 or WU95 with time, nor did it slow the rate of decline in nodule occupancy of WU95.

Boron deficiency in pasture based on subterranean clover (Trifolium subterraneum L.) is linked to symbiotic malfunction

2015 ◽  
Vol 66 (11) ◽  
pp. 1197 ◽  
Author(s):  
Leo J. Hamilton ◽  
Kevin F. M. Reed ◽  
Elainne M. A. Leach ◽  
John Brockwell
Keyword(s):  
N2 Fixation ◽  
Rhizobium Leguminosarum ◽  
Root Nodule ◽  
Effective Strain ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Boron Deficiency ◽  
Initial Application ◽  
Clover Root ◽  
Clover Seed

Field and glasshouse experiments confirmed the occurrence of boron (B) deficiency in subterranean clover (Trifolium subterraneum L.) pasture in eastern Victoria. Diminished productivity was linked to the small-seededness of clover and the poor effectiveness of clover root-nodule bacteria (rhizobia, Rhizobium leguminosarum bv. trifolii). Productivity, especially of clover and clover seed, increased following applications of up to 6 kg B ha–1 (P < 0.001). The response was delayed, occurring several years after the initial application of B, unless the land was resown with fresh clover seed inoculated with an effective strain of rhizobia. B deficiency in the nodulated legume induced conditions within the plant and or its rhizobia that led to impaired nitrogen (N2) fixation. Glasshouse research indicated that populations of soil-borne rhizobia taken from B-deficient soils were poorly effective in N2 fixation and that rhizobia from soils growing subterranean clover cv. Leura were significantly less effective (P < 0.05) than rhizobia from a soil growing cv. Mt Barker. Additionally, subterranean clover seed generated in B-deficient soils was at least one-third smaller than the seed of commercial seed but responded to inoculation with effective rhizobia. This indicated that any symbiotic malfunction of clover from B-deficient soils was not due to an inability to respond to nitrogen per se. On the other hand, cv. Leura from B-deficient soils fixed significantly less N2 than commercial cv. Leura when each was inoculated with rhizobia from B-deficient soils.

scholarly journals Urana subterranean clover (Trifolium subterraneum L. var. subterraneum)

2006 ◽  
Vol 46 (8) ◽  
pp. 1105 ◽  
Author(s):  
P. G. H. Nichols ◽  
M. J. Barbetti ◽  
G. A. Sandral ◽  
B. S. Dear ◽  
C. T. de Koning ◽  
...  
Keyword(s):  
New South ◽  
South Australia ◽  
Field Performance ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Crop Rotations ◽  
Improvement Program ◽  
South Wales ◽  
Pasture Legume

Urana is a hardseeded, moderately early flowering F5-derived crossbred subterranean clover of var. subterraneum [(Katz. et Morley) Zohary and Heller] developed by the collaborating organisations of the National Annual Pasture Legume Improvement Program. It has been selected for release as a new cultivar on the basis of its high winter and spring herbage production and overall field performance relative to other subterranean clovers of similar maturity. Urana is recommended for sowing in Western Australia, New South Wales, Victoria, South Australia and Queensland. It is best suited to well-drained, moderately acidic soils in areas with a growing season of 5–7 months, which extends into mid-October. Urana is suited to phase farming and crop rotations. It has been granted Plant Breeders Rights in Australia.

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