scholarly journals In vitro evidence of root colonization suggests ecological versatility in the genus Mycena

2020 ◽  
Vol 227 (2) ◽  
pp. 601-612 ◽  
Author(s):  
Ella Thoen ◽  
Christoffer Bugge Harder ◽  
Håvard Kauserud ◽  
Synnøve S. Botnen ◽  
Unni Vik ◽  
...  
Keyword(s):  
Root Colonization ◽  
Ecological Versatility

scholarly journals A prospectus of plant growth promoting endophytic bacterium from orchid (Vanda cristata)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sujit Shah ◽  
Krishna Chand ◽  
Bhagwan Rekadwad ◽  
Yogesh S. Shouche ◽  
Jyotsna Sharma ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Colonization ◽  
Endophytic Bacterium ◽  
Epifluorescence Microscopy ◽  
In Vitro Cultivation ◽  
Rrna Gene ◽  
Bacillus Spp ◽  
Plant Growth Promoting ◽  
Growth Promoting

Abstract Background A plant growth-promoting endophytic bacterium PVL1 isolated from the leaf of Vanda cristata has the ability to colonize with roots of plants and protect the plant. PVL1 was isolated using laboratory synthetic media. 16S rRNA gene sequencing method has been employed for identification before and after root colonization ability. Results Original isolated and remunerated strain from colonized roots were identified as Bacillus spp. as per EzBiocloud database. The presence of bacteria in the root section of the plantlet was confirmed through Epifluorescence microscopy of colonized roots. The in-vitro plantlet colonized by PVL1 as well as DLMB attained higher growth than the control. PVL1 capable of producing plant beneficial phytohormone under in vitro cultivation. HPLC and GC-MS analysis suggest that colonized plants contain Indole Acetic Acid (IAA). The methanol extract of Bacillus spp., contains 0.015 μg in 1 μl concentration of IAA. PVL1 has the ability to produce antimicrobial compounds such as ethyl iso-allocholate, which exhibits immune restoring property. One-way ANOVA shows that results were statistically significant at P ≤ 0.05 level. Conclusions Hence, it has been concluded that Bacillus spp. PVL1 can promote plant growth through secretion of IAA during root colonization and ethyl iso-allocholate to protect plants from foreign infections. Thus, this study supports to support Koch’s postulates of bacteria establishment.

scholarly journals Deletion of Rap‐Phr systems in Bacillus subtilis influences in vitro biofilm formation and plant root colonization

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Mathilde Nordgaard ◽  
Rasmus Møller Rosenbek Mortensen ◽  
Nikolaj Kaae Kirk ◽  
Ramses Gallegos‐Monterrosa ◽  
Ákos T. Kovács
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Root Colonization ◽  
Plant Root

Evaluation of the phytotoxicity of 2,4-diacetylphloroglucinol and Pseudomonas brassicacearum Q8r1-96 on different wheat cultivars

2021 ◽  
Author(s):  
Mingming Yang ◽  
Linda S Thomashow ◽  
David M Weller
Keyword(s):  
Seed Germination ◽  
Pacific Northwest ◽  
Root Colonization ◽  
The United States ◽  
Wheat Cultivars ◽  
The Pacific ◽  
Root Necrosis ◽  
Growth Promoting ◽  
Pseudomonas Brassicacearum

Pseudomonas brassicacearum Q8r1-96 and other 2,4-diacetylphloroglucinol (DAPG)-producing pseudomonads of the Pseudomonas fluorescens complex possess both biocontrol and growth-promoting properties and play an important role in suppression of take-all of wheat in the Pacific Northwest (PNW) of the United States. However, P. brassicacearum can also reduce seed germination and cause root necrosis on some wheat cultivars. We evaluated the effect of Q8r1-96 and DAPG on the germination of 69 wheat cultivars that have been or currently are grown in the PNW. Cultivars varied widely in their ability to tolerate P. brassicacearum or DAPG. The frequency of germination of the cultivars ranged from 0 to 0.87 and from 0.47 to 0.90 when treated with Q8r1-96 and DAPG, respectively. There was a significant positive correlation between the frequency of germination of cultivars treated with Q8r1-96 in assays conducted in vitro and in the greenhouse. The correlation was greater for spring than for winter cultivars. In contrast, the effect of Q8r1-96 on seed germination was not correlated with that of DAPG alone, suggesting that DAPG is not the only factor responsible for the phytotoxicity of Q8r1-96. Three wheat cultivars with the greatest tolerance and three cultivars with the least tolerance to Q8r1-96 were tested for their ability to support root colonization by strain Q8r1-96. Cultivars with the greatest tolerance supported significantly greater populations of strain Q8r1-96 than those with the least tolerance to the bacteria. Our results show that wheat cultivars differ widely in their interaction with P. brassicacearum and the biocontrol antibiotic DAPG.

External and internal root colonization of lodgepole pine seedlings by two growth-promoting Bacillus strains originated from different root microsites

1995 ◽  
Vol 41 (8) ◽  
pp. 707-713 ◽  
Author(s):  
M. Shishido ◽  
B. M. Loeb ◽  
C. P. Chanway
Keyword(s):  
Root Colonization ◽  
Lodgepole Pine ◽  
Substrate Utilization ◽  
Root Tissue ◽  
Pine Seedlings ◽  
Growth Promoting ◽  
Root Tissues ◽  
Bacillus Strains ◽  
Fresh Root

Root colonization and in vitro carbon substrate utilization by two seedling growth-promoting Bacillus strains that originated from different root microsites were studied in greenhouse and growth chamber experiments. Strain L6, identified as Bacillus polymyxa, was previously isolated from rhizosphere soil containing roots of pasture plants, and Pw-2, tentatively identified also as B. polymyxa, was isolated from within surface-sterilized lodgepole pine (Pinus contorta var. latifolia (Dougl.) Engelm.) roots. Rifamycin-resistant strains derived spontaneously from wild-type strains L6 and Pw-2, designated strain L6-16R and Pw-2R, respectively, were used to monitor lodgepole pine root colonization in a closed tube assay system. Three-week-old pine seedlings were inoculated with 105 colony-forming units (cfu) of strain Pw-2R or 106 cfu of strain L6-16R, and external and internal root colonization was assessed 2 and 4 weeks later. Strains L6-16R and Pw-2R were both recovered from pine rhizosphere samples with > 5 × 107 cfu/g fresh root tissue 2 weeks after inoculation, but neither strain was detected in the root interior. When root colonization was assessed 4 weeks after inoculation, the rhizosphere populations of both strains had declined slightly to between 5 × 106 and 5 × 107 cfu/g fresh root tissue, but strain Pw-2R was also detected within root tissues with 105 cfu/g fresh root tissue. Lateral root formation was abundant 4 weeks after inoculation and may have facilitated colonization of internal root tissues by strain Pw-2R. Both strains possessed pectolytic activity, although differences between the strains were detected in in vitro substrate utilization capabilities using BIOLOG assays. These differences may be related to their abilities to colonize internal root tissues. On the basis of our results, we hypothesize that internal root colonization by Bacillus strains is not a random event and that root-endophytic Bacillus strains possess specific physiological and (or) biochemical characteristics that facilitate colonization of internal root tissues.Key words: Bacillus, PGPR, rhizosphere, endophytes, colonization.

scholarly journals Contribution of Bacillomycin D in Bacillus amyloliquefaciens SQR9 to Antifungal Activity and Biofilm Formation

2012 ◽  
Vol 79 (3) ◽  
pp. 808-815 ◽  
Author(s):  
Zhihui Xu ◽  
Jiahui Shao ◽  
Bing Li ◽  
Xin Yan ◽  
Qirong Shen ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Root Colonization ◽  
Antagonistic Activity ◽  
Vital Role ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Bacillomycin D

ABSTRACTBacillus amyloliquefaciensstrains are capable of suppressing soilborne pathogens through the secretion of an array of lipopeptides and root colonization, and biofilm formation ability is considered a prerequisite for efficient root colonization. In this study, we report that one of the lipopeptide compounds (bacillomycin D) produced by the rhizosphere strainBacillus amyloliquefaciensSQR9 not only plays a vital role in the antagonistic activity againstFusarium oxysporumbut also affects the expression of the genes involved in biofilm formation. When the bacillomycin D and fengycin synthesis pathways were individually disrupted, mutant SQR9M1, which was deficient in the production of bacillomycin D, only showed minor antagonistic activity againstF. oxysporum, but another mutant, SQR9M2, which was deficient in production of fengycin, showed antagonistic activity equivalent to that of the wild-type strain ofB. amyloliquefaciensSQR9. The results fromin vitro, rootin situ, and quantitative reverse transcription-PCR studies demonstrated that bacillomycin D contributes to the establishment of biofilms. Interestingly, the addition of bacillomycin D could significantly increase the expression levels ofkinCgene, but KinC activation is not triggered by leaking of potassium. These findings suggest that bacillomycin D contributes not only to biocontrol activity but also to biofilm formation in strainB. amyloliquefaciensSQR9.

scholarly journals Assessment of the Effectiveness of Ectomycorrhizal Inocula to Promote Growth and Root Ectomycorrhizal Colonization inPinus patulaSeedlings Using the Most Probable Number Technique

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Manuel Restrepo-Llano ◽  
Nelson W. Osorio ◽  
Juan D. León
Keyword(s):  
Root Colonization ◽  
Most Probable Number ◽  
Pinus Patula ◽  
Forest Plantations ◽  
High Quality ◽  
Probable Number ◽  
Key Factor ◽  
Ectomycorrhizal Colonization ◽  
Forest Nurseries

The aim of this study was to evaluate the response ofPinus patulaseedlings to two inocula types: soil from aPinusplantation (ES) and anin vitroproduced inoculum (EM). The most probable number method (MPN) was used to quantify ectomycorrhizal propagule density (EPD) in both inocula in a 7-order dilution series ranging from 100(undiluted inoculum) to 10−6(the most diluted inoculum). The MPN method allowed establishing differences in the number of infective ectomycorrhizal propagules’ density (EPD) (ES=34per g;EM=156per g). The results suggest that the EPD of an inoculum may be a key factor that influences the successfulness of the inoculation. The low EPD of the ES inoculum suggests that soil extracted from forest plantations had very low effectiveness for promoting root colonization and plant growth. In contrast, the high EPD found in the formulated inoculum (EM) reinforced the idea that it is better to use proven high quality inocula for forest nurseries than using soil from a forestry plantation.

scholarly journals Visualization of Interactions Between a Pathogenic and a Beneficial Fusarium Strain During Biocontrol of Tomato Foot and Root Rot

2005 ◽  
Vol 18 (7) ◽  
pp. 710-721 ◽  
Author(s):  
Annouschka Bolwerk ◽  
Anastasia L. Lagopodi ◽  
Ben J. J. Lugtenberg ◽  
Guido V. Bloemberg
Keyword(s):  
Root Rot ◽  
Laser Scanning ◽  
Root Colonization ◽  
Pathogenic Fungus ◽  
Laser Scanning Microscopy ◽  
Systemic Resistance ◽  
Confocal Laser ◽  
Tomato Root ◽  
Tomato Roots

The soilborne fungus Fusarium oxysporum f. sp. radicislycopersici causes tomato foot and root rot (TFRR), which can be controlled by the addition of the nonpathogenic fungus F. oxysporum Fo47 to the soil. To improve our understanding of the interactions between the two Fusarium strains on tomato roots during biocontrol, the fungi were labeled using different autofluorescent proteins as markers and subsequently visualized using confocal laser scanning microscopy. The results were as follows. i) An at least 50- fold excess of Fo47over F. oxysporum f. sp. radicis-lycopersici was required to obtain control of TFRR. ii) When seedlings were planted in sand infested with spores of a single fungus, Fo47 hyphae attached to the root earlier than those of F. oxysporum f. sp. radicis-lycopersici. iii) Subsequent root colonization by F. oxysporum f. sp. radicis-lycopersici was faster and to a larger extent than that by Fo47. iv) Under disease-controlling conditions, colonization of tomato roots by the pathogenic fungus was significantly reduced. v) When the inoculum concentration of Fo47 was increased, root colonization by the pathogen was arrested at the stage of initial attachment to the root. vi) The percentage of spores of Fo47 that germinates in tomato root exudate in vitro is higher than that of the pathogen F. oxysporum f. sp. radicis-lycopersici. Based on these results, the mechanisms by which Fo47 controls TFRR are discussed in terms of i) rate of spore germination and competition for nutrients before the two fungi reach the rhizoplane; ii) competition for initial sites of attachment, intercellular junctions, and nutrients on the tomato root surface; and iii) inducing systemic resistance.

Chemotaxis of fluorescent Pseudomonas spp. to soybean seed exudates in vitro and in soil

1985 ◽  
Vol 31 (6) ◽  
pp. 570-574 ◽  
Author(s):  
F. M. Scher ◽  
J. W. Kloepper ◽  
C. A. Singleton
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Root Colonization ◽  
Soybean Seed ◽  
New Method ◽  
Bacterial Suspension ◽  
Soybean Seeds ◽  
Fluorescent Pseudomonas ◽  
Colony Forming Units

Five seed-colonizing fluorescent Pseudomonas strains (RW1 to RW5) exhibited chemotaxis toward soybean seed exudates in 1-μL capillaries held for 30 min in an 8.0 log colony-forming units/mL bacterial suspension over the temperature range of 9 to 41 °C. Dialysis (6000 molecular weight cut-off) of exudate nullified its attractiveness to RW1; heating (121 °C, 15 min) of exudate had no effect. Several amino acids present in exudate induced a chemotactic response by RW1, and asparagine, threonine, and valine at levels in exudate were as attractive as exudate. No chemotaxis by RW1 was observed toward sugars present in exudate. RW1 to RW5 actively migrated 1 cm toward soybean seeds in soil as demonstrated by a new method. A nonmotile mutant of RW3 did not migrate in soil and no significant migration by strains was observed when no seed or exudate was present. It is suggested that chemotaxis of Pseudomonas toward seed exudates may be the first step in establishment of bacterial seed and root colonization in soil.

scholarly journals Effects onGlomus mosseaeRoot Colonization byPaenibacillus polymyxaandPaenibacillus brasilensisStrains as Related to Soil P-Availability in Winter Wheat

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Veronica Arthurson ◽  
Karin Hjort ◽  
Diriba Muleta ◽  
Lotta Jäderlund ◽  
Ulf Granhall
Keyword(s):  
Plant Growth ◽  
Winter Wheat ◽  
Plant Uptake ◽  
Root Colonization ◽  
Mycorrhizal Fungus ◽  
Soil Conditions ◽  
P Availability ◽  
Plant Host ◽  
Total Plant

Greenhouse experiments were conducted to assess the effects of inoculating winter wheat (Triticum aestivum) with plant growth promoting rhizobacteria (PGPR) of the genusPaenibacillusunder phosphate P-limited soil conditions in the presence or absence of the arbuscular mycorrhizal fungus (AMF)Glomus mosseae. FourP. polymyxastrains and oneP. brasilensisstrain were compared at two cell concentrations (106and 108 cells g−1seeds) of inoculation, and surface sterilized AMF spores were added to pots. Mycorrhizal root colonization, plant growth, and plant uptake of phosphorus were analyzed. Bacterial phosphate solubilization was examined separatelyin vitro. MostP. polymyxastrains, isolated from wheat, had dramatic effectsper seon root growth and root P-content. No treatment gave significant effect on shoot growth. AMF root colonization levels and total plant uptake of P were much stimulated by the addition of mostP. polymyxastrains. The AM fungus alone and theP. brasilensis, alone or in combination with the fungus, did not affect total plant P-levels. Our results indicate that practical application of inoculation with plant host-specific rhizobacteria (i.e.,P. polymyxa) could positively influence uptake of phosphorus in P-deficient soils by wheat plants, provided that suitable AM fungi (e.g.,G. mosseae) are present.

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