Interaction of Rhizobia with Soil Suppressiveness Factors

Abstract Soil suppressiveness which is the natural ability of soil to support optimal plant growth and health is the resultant of multiple soil microbial components; which implies many difficulties when estimating this soil condition. Microbial benefits for plant health from repeated digestate applications were assessed in three experimental sites surrounding anaerobic biogas plants in an intensively cultivated area of northern Italy. A 2-yr trial was performed in 2017 and 2018 by performing an in-pot plant growth assay, using soil samples taken from two fields for each experimental site, of which one had been repeatedly amended with anaerobic biogas digestate and the other had not. These fields were similar in management and crop sequences (maize was the recurrent crop) for the last 10 yr. Plant growth response in the bioassay was expressed as plant biomass production, root colonization frequency by soil-borne fungi were estimated to evaluate the impact of soil-borne pathogens on plant growth, abundance of Pseudomonas and actinomycetes populations in rhizosphere were estimated as beneficial soil microbial indicators. Repeated soil amendment with digestate increased significantly soil capacity to support plant biomass production as compared to unamended control in both the years. Findings supported evidence that this increase was principally attributable to a higher natural ability of digestate-amended soils to reduce root infection by saprophytic soil-borne pathogens whose inoculum was increased by the recurrent maize cultivation. Pseudomonas and actinomycetes were always more abundant in digestate-amended soils suggesting that both these large bacterial groups were involved in the increase of their natural capacity to control soil-borne pathogens (soil suppressiveness).

Download Full-text

Induction of Soil Suppressiveness Against Rhizoctonia solani by Incorporation of Dried Plant Residues into Soil

Phytopathology ◽

10.1094/phyto-96-1372 ◽

2006 ◽

Vol 96 (12) ◽

pp. 1372-1379 ◽

Cited By ~ 19

Author(s):

Masahiro Kasuya ◽

Andriantsoa R. Olivier ◽

Yoko Ota ◽

Motoaki Tojo ◽

Hitoshi Honjo ◽

...

Keyword(s):

Rhizoctonia Solani ◽

Mycelial Growth ◽

Inhibitory Effect ◽

Volatile Substance ◽

Disease Suppression ◽

Plant Residues ◽

Infested Soil ◽

Antagonistic Bacteria ◽

Damping Off ◽

Soil Suppressiveness

Suppressive effects of soil amendment with residues of 12 cultivars of Brassica rapa on damping-off of sugar beet were evaluated in soils infested with Rhizoctonia solani. Residues of clover and peanut were tested as noncruciferous controls. The incidence of damping-off was significantly and consistently suppressed in the soils amended with residues of clover, peanut, and B. rapa subsp. rapifera ‘Saori’, but only the volatile substance produced from water-imbibed residue of cv. Saori exhibited a distinct inhibitory effect on mycelial growth of R. solani. Nonetheless, disease suppression in such residue-amended soils was diminished or nullified when antibacterial antibiotics were applied to the soils, suggesting that proliferation of antagonistic bacteria resident to the soils were responsible for disease suppression. When the seed (pericarps) colonized by R. solani in the infested soil without residues were replanted into the soils amended with such residues, damping-off was suppressed in all cases. In contrast, when seed that had been colonized by microorganisms in the soils containing the residues were replanted into the infested soil, damping-off was not suppressed. The evidence indicates that the laimosphere, but not the spermosphere, is the site for the antagonistic microbial interaction, which is the chief principle of soil suppressiveness against Rhizoctonia damping-off.

Download Full-text

Molecular Identification of Fungal Communities in a Soil Cultivated with Vegetables and Soil Suppressiveness toRhizoctonia solani

Applied and Environmental Soil Science ◽

10.1155/2013/268768 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Silvana Pompéia Val-Moraes ◽

Eliamar Aparecida Nascimbem Pedrinho ◽

Eliana Gertrudes Macedo Lemos ◽

Lucia Maria Carareto-Alves

Keyword(s):

Biotic Interactions ◽

Fungal Communities ◽

Native Forest ◽

Metagenomic Dna ◽

Soil Suppressiveness ◽

Rdna Sequences ◽

Pcr Products ◽

Realistic View ◽

18S Rdna Sequences ◽

Total Dna

Fungi constitute an important part of the soil ecosystem, playing key roles in decomposition, cycling processes, and biotic interactions. Molecular methods have been used to assess fungal communities giving a more realistic view of their diversity. For this purpose, total DNA was extracted from bulk soils cultivated with tomato (STC), vegetables (SHC), and native forest (SMS) from three sites of the Taquara Branca river basin in Sumaré County, São Paulo State, Brazil. This metagenomic DNA was used as a template to amplify fungal 18S rDNA sequences, and libraries were constructed inEscherichia coliby cloning PCR products. The plasmid inserts were sequenced and compared to known rDNA sequences in the GenBank database. Of the sequenced clones, 22 were obtained from the SMS sample, 18 from the SHC sample, and 6 from the STC sample. Although most of the clone sequences did not match the sequences present in the database, individual amplified sequences matched with Glomeromycota (SMS), Fungi incertae sedis (SMS), and Neocallimastigomycota (SHC). Most of the sequences from the amplified taxa represent uncultured fungi. The molecular analysis of variance (AMOVA) indicated that fluctuations observed of haplotypes in the composition may be related to herbicide application.

Download Full-text

Biological Suppression of Velvetleaf (Abutilon theophrasti) in an Eastern Nebraska Soil

Weed Science ◽

10.1614/ws-d-10-00115.1 ◽

2011 ◽

Vol 59 (2) ◽

pp. 155-161 ◽

Cited By ~ 1

Author(s):

Jane Okalebo ◽

Gary Y. Yuen ◽

Rhae A. Drijber ◽

Erin E. Blankenship ◽

Cafer Eken ◽

...

Keyword(s):

Management Practices ◽

Reproductive Potential ◽

Nutrient Content ◽

Research Field ◽

Soil Suppressiveness ◽

Plant Soil ◽

Fusarium Lateritium ◽

Heat Treated ◽

Soil Feedback ◽

Chemical Factors

Weed-suppressive soils contain naturally occurring microorganisms that suppress a weed by inhibiting its growth, development, and reproductive potential. Increased knowledge of microbe–weed interactions in such soils could lead to the identification of management practices that create or enhance soil suppressiveness to weeds. Velvetleaf death and growth suppression was observed in a research field (fieldA) that was planted with high populations of velvetleaf, which may have developed via microbial mediated plant–soil feedback. Greenhouse studies were conducted with soil collected fromfieldA(soilA) to determine if it was biologically suppressive to velvetleaf. In one study, mortality of velvetleaf grown for 8 wk insoilAwas greatest (86%) and biomass was smallest (0.3 g plant−1) in comparison to soils collected from surrounding fields with similar structure and nutrient content, indicating that suppressiveness ofsoilAwas not likely caused by physical or chemical factors. WhensoilAwas autoclaved in another study, mortality of velvetleaf plants in the heat-treated soil was reduced to 4% compared to 55% for the untreated soil, thus suggesting that suppressiveness ofsoilAis biological in nature. A third set of experiments showed that suppressiveness to velvetleaf could be transferred to an autoclaved soil by amending the autoclaved soil with untreatedsoilA; this provided additional evidence for a biological basis for the effects ofsoilA.The suppressive condition in these greenhouse experiments was associated with high soil populations of fusaria.Fusarium lateritiumwas the most frequently isolated fungus from roots of diseased velvetleaf plants collected fromfieldA, and also was the most virulent when inoculated onto velvetleaf seedlings. Results of this research indicate that velvetleaf suppression can occur naturally in the field and thatF. lateritiumis an important cause of velvetleaf mortality infieldA.

Download Full-text

Function and Distribution of a Lantipeptide in Strawberry Fusarium Wilt Disease–Suppressive Soils

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-05-18-0129-r ◽

2019 ◽

Vol 32 (3) ◽

pp. 306-312 ◽

Cited By ~ 6

Author(s):

Da-Ran Kim ◽

Chang-Wook Jeon ◽

Jae-Ho Shin ◽

David M. Weller ◽

Linda Thomashow ◽

...

Keyword(s):

Fusarium Wilt ◽

Streptomyces Griseus ◽

Class Ii ◽

Wilt Disease ◽

Genus Streptomyces ◽

Soil Suppressiveness ◽

Streptomyces Spp ◽

Heat Stable ◽

Fusarium Wilt Disease ◽

Polymerase Chain

Streptomyces griseus S4-7 is representative of strains responsible for the specific soil suppressiveness of Fusarium wilt of strawberry caused by Fusarium oxysporum f. sp. fragariae. Members of the genus Streptomyces secrete diverse secondary metabolites including lantipeptides, heat-stable lanthionine-containing compounds that can exhibit antibiotic activity. In this study, a class II lantipeptide provisionally named grisin, of previously unknown biological function, was shown to inhibit F. oxysporum. The inhibitory activity of grisin distinguishes it from other class II lantipeptides from Streptomyces spp. Results of quantitative reverse transcription-polymerase chain reaction with lanM-specific primers showed that the density of grisin-producing Streptomyces spp. in the rhizosphere of strawberry was positively correlated with the number of years of monoculture and a minimum of seven years was required for development of specific soil suppressiveness to Fusarium wilt disease. We suggest that lanM can be used as a diagnostic marker of whether a soil is conducive or suppressive to the disease.

Download Full-text

Impact of Green Manure and Vermicompost on Soil Suppressiveness, Soil Microbial Populations, and Plant Growth in Conditions of Organic Agriculture of Northern Temperate Climate

Soil Biology - Organic Amendments and Soil Suppressiveness in Plant Disease Management ◽

10.1007/978-3-319-23075-7_18 ◽

2015 ◽

pp. 381-399 ◽

Cited By ~ 2

Author(s):

L. Grantina-Ievina ◽

V. Nikolajeva ◽

N. Rostoks ◽

I. Skrabule ◽

L. Zarina ◽

...

Keyword(s):

Plant Growth ◽

Organic Agriculture ◽

Green Manure ◽

Microbial Populations ◽

Temperate Climate ◽

Soil Suppressiveness ◽

Soil Microbial

Download Full-text

Microflora of Meloidogyne egg masses: species composition, population density and effect on the biocontrol agent Verticillium chlamydosporium (Goddard)

Nematology ◽

10.1163/156854101753625236 ◽

2001 ◽

Vol 3 (8) ◽

pp. 729-734 ◽

Cited By ~ 28

Author(s):

C.J.(Hans) Kok ◽

Artemis Papert ◽

C.B.(Chula) Bok-A-Bin

Keyword(s):

Bacterial Population ◽

Biocontrol Agent ◽

Bacterial Species ◽

Antagonistic Activity ◽

Parasitic Fungus ◽

Egg Mass ◽

Egg Masses ◽

Soil Suppressiveness ◽

Verticillium Chlamydosporium

AbstractEgg masses of Meloidogyne fallax from tomato and potato growing in soil from a nematode suppressive and a nonsuppressive field sustained bacterial population densities two to three orders of magnitude higher than those of the rhizosphere soil. BIOLOG metabolic profiling identified 16 bacterial species from egg masses. Results further indicated 20 species not listed in the BIOLOG database. 122 isolates of bacteria and 19 isolates of fungi from M. fallax or M. hapla were tested for in vitro antagonism against the nematode egg parasitic fungus Verticillium chlamydosporium: 23% of the bacteria and 74% of the fungi showed antagonistic activity. Pseudomonads showed an overall stronger antagonistic activity than the other bacteria. Our conclusions are that Meloidogyne egg masses are a densely populated microbial niche and that their microflora may well be an important factor in determining the success of nematode antagonists. However, we could not find a relationship between the egg mass microflora and differences in soil suppressiveness between the sample sites.

Download Full-text