Potato plant spheres and to a lesser extent the soil type influence the proportion and diversity of bacterial isolates with in vitro antagonistic activity towards Ralstonia solanacearum

2021 ◽  
Vol 97 (4) ◽  
Author(s):  
Tarek R Elsayed ◽  
Rita Grosch ◽  
Kornelia Smalla
Keyword(s):  
Ralstonia Solanacearum ◽  
Soil Type ◽  
Potato Plant ◽  
Antagonistic Activity ◽  
Bulk Soil ◽  
Soil Types ◽  
Sample Type ◽  
Bacterial Isolates ◽  
Potato Plants

ABSTRACT Ralstonia solanacearum biovar2-race3 (Rs r3b2) is an epidemic soil-borne bacterial phytopathogen causing brown rot disease in potato. In this study, we assessed how three soil types stored at the same field site influenced the proportion and diversity of bacterial isolates with in vitro antagonistic activity towards Rs in bulk soil and different potato plant spheres (rhizosphere, endorhiza and endocaulosphere; ecto- and endosphere of seed and yield tubers). In general, the plate counts observed for each sample type were not significantly different. A total of 96 colonies per sample type was picked and screened for in vitro antagonistic activity against Rs. Antagonists were obtained from all bulk soils and plant spheres with the highest proportion obtained from the endorhiza and endocaulosphere of potato plants. BOX-PCR fingerprints of antagonists showed that some were specific for particular plant spheres independent of the soil type, while others originated from different plant spheres of a particular soil type. The majority of antagonists belonged to Pseudomonas. A high proportion of antagonists produced siderophores, and interestingly antagonists from potato tubers frequently carried multiple antibiotic production genes. Our data showed an enrichment of bacteria with genes or traits potentially involved in biocontrol in the rhizosphere and in endophytic compartments. We report that the proportion and diversity of in vitro antagonists towards Rs isolated from bulk soil and different spheres of potato plants grown under field conditions in three different soil types was mainly shaped by the plant sphere and to a lesser extent by the soil type. Bacteria with antagonistic activity towards Ralstonia solanacearum were isolated from all plant spheres and bulk soils but their proportion was highest in endophytic compartments

scholarly journals Biocontrol of the Potato Blackleg and Soft Rot Diseases Caused by Dickeya dianthicola

2015 ◽  
Vol 82 (1) ◽  
pp. 268-278 ◽  
Author(s):  
Yannick Raoul des Essarts ◽  
Jérémy Cigna ◽  
Angélique Quêtu-Laurent ◽  
Aline Caron ◽  
Euphrasie Munier ◽  
...  
Keyword(s):  
Soft Rot ◽  
Potato Production ◽  
Biocontrol Agents ◽  
Bacterial Isolates ◽  
Potato Blackleg ◽  
Content Type ◽  
Potato Plants ◽  
Potential Strategy

ABSTRACTDevelopment of protection tools targetingDickeyaspecies is an important issue in the potato production. Here, we present the identification and the characterization of novel biocontrol agents. Successive screenings of 10,000 bacterial isolates led us to retain 58 strains that exhibited growth inhibition properties against severalDickeyasp. and/orPectobacteriumsp. pathogens. Most of them belonged to thePseudomonasandBacillusgenera.In vitroassays revealed a fitness decrease of the testedDickeyasp. andPectobacteriumsp. pathogens in the presence of the biocontrol agents. In addition, four independent greenhouse assays performed to evaluate the biocontrol bacteria effect on potato plants artificially contaminated withDickeya dianthicolarevealed that a mix of three biocontrol agents, namely,Pseudomonas putidaPA14H7 andPseudomonas fluorescensPA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission ofD. dianthicolato the tuber progeny. This work highlights the use of a combination of biocontrol strains as a potential strategy to limit the soft rot and blackleg diseases caused byD. dianthicolaon potato plants and tubers.

scholarly journals Plant-Dependent Genotypic and Phenotypic Diversity of Antagonistic Rhizobacteria Isolated from Different Verticillium Host Plants

2002 ◽  
Vol 68 (7) ◽  
pp. 3328-3338 ◽  
Author(s):  
Gabriele Berg ◽  
Nicolle Roskot ◽  
Anette Steidle ◽  
Leo Eberl ◽  
Angela Zock ◽  
...  
Keyword(s):  
Plant Species ◽  
Oilseed Rape ◽  
Phenotypic Diversity ◽  
Acid Methyl Ester ◽  
Pathogenic Fungi ◽  
Genotypic Diversity ◽  
Antagonistic Activity ◽  
Bulk Soil ◽  
Microtiter Plates

ABSTRACT To study the effect of plant species on the abundance and diversity of bacterial antagonists, the abundance, the phenotypic diversity, and the genotypic diversity of rhizobacteria isolated from potato, oilseed rape, and strawberry and from bulk soil which showed antagonistic activity towards the soilborne pathogen Verticillium dahliae Kleb. were analyzed. Rhizosphere and soil samples were taken five times over two growing seasons in 1998 and 1999 from a randomized field trial. Bacterial isolates were obtained after plating on R2A (Difco, Detroit, Mich.) or enrichment in microtiter plates containing high-molecular-weight substrates followed by plating on R2A. A total of 5,854 bacteria isolated from the rhizosphere of strawberry, potato, or oilseed rape or bulk soil from fallow were screened by dual testing for in vitro antagonism towards Verticillium. The proportion of isolates with antagonistic activity was highest for strawberry rhizosphere (9.5%), followed by oilseed rape (6.3%), potato (3.7%), and soil (3.3%). The 331 Verticillium antagonists were identified by their fatty acid methyl ester profiles. They were characterized by testing their in vitro antagonism against other pathogenic fungi; their glucanolytic, chitinolytic, and proteolytic activities; and their BOX-PCR fingerprints. The abundance and composition of Verticillium antagonists was plant species dependent. A rather high proportion of antagonists from the strawberry rhizosphere was identified as Pseudomonas putida B (69%), while antagonists belonging to the Enterobacteriaceae (Serratia spp., Pantoea agglomerans) were mainly isolated from the rhizosphere of oilseed rape. For P. putida A and B plant-specific genotypes were observed, suggesting that these bacteria were specifically enriched in each rhizosphere.

scholarly journals Antagonistic Activity and Characterization of Indigenous Soil Isolates of Bacteria and Fungi Against Onion Wilt Incited by Fusarium sp

2021 ◽  
Author(s):  
Hilda Karim ◽  
Andi Asmawati ◽  
Oslan Jumadi
Keyword(s):  
Fusarium Oxysporum ◽  
Evolutionary Relationship ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
Bacterial Isolates ◽  
Gene Markers ◽  
Culture Techniques ◽  
Fungal Isolates ◽  
Bacteria And Fungi

Abstract Tuber rot disease due to phytopathogen Fusarium oxysporum f. sp. cepae (Foc) infection is one of the main factors causing the decreasing amount of global shallot production. This study aims to find bacteria and fungi candidates which have Foc antagonistic activity through in vitro tests using dual culture techniques. A total of five bacterial isolates and three fungal isolates isolated from the rhizosphere of healthy onion plants showed the ability to inhibit Foc growth. B1 and B4 bacterial isolates had an average inhibitory capability of 65.93% and 72.27% respectively. Whereas C1 and C2 fungal isolates have the ability to inhibit the growth of Foc by as much as 74.82% and 67.76% respectively. The four tested microbial isolates were able to significantly inhibit Foc activity in vitro based on the ANOVA test, with values α = 0.05, and n = 3. Molecular analysis based on 16S-rRNA markers showed bacterial isolates B1 and B4 have an evolutionary relationship with B. subtilis. Whereas fungi C1 and C2 have evolutionary relationships with Aspergillus tubingensis and Trichoderma asperellum respectively, based on internal transcribed spacer (ITS) gene markers. The results of this study can be used to develop indigenous microbial consortiums as biological control agents for phytopathogenic fungi Fusarium oxysporum f. sp. cepae (Foc) on shallots.

scholarly journals Effects of soil type on density of trees and nutritive value of tree leaves in selected communal areas of South Africa

2020 ◽  
Vol 50 (1) ◽  
pp. 88-98
Author(s):  
K.E. Ravhuhali ◽  
V Mlambo ◽  
T.S. Beyene ◽  
L.G. Palamuleni
Keyword(s):  
South Africa ◽  
Soil Type ◽  
Crude Protein ◽  
Nutritive Value ◽  
Plant Density ◽  
Canopy Cover ◽  
Soil Types ◽  
Crude Protein Content ◽  
Loamy Soil

This study aimed to describe the distribution and nutritive value of woody species growing in clay-loamy and red-brown sand from selected localities of North West, South Africa. Three 2.2 km transects, radiating from homesteads, which served as replicates, were established at each of four selected grazing areas. Nine 10 × 10 m homogenous vegetation units (HVU), 20 m apart, were marked in each transect. Woody plant density, height and canopy cover (CC), were recorded, and chemical properties and degradability via in vitro ruminal fermentation of harvested leaves were measured. Raisin bush (Grewia flava), Buffalo thorn (Ziziphus mucronata) and Camel thorn (Vachellia erioloba) were the common species across both soil types. Soil type influenced (P <0.05) plant density, CC, total tree equivalent (TTE) and plant height. Areas with red-brown sandy soil had higher (P <0.05) total plant density (827.7 plant/ha), CC (9.6%) and TTE (2886.4 TTE/ha) than those with clay-loamy soil. Vachellia erioloba leaves in clay-loamy soil had the highest (P <0.05) crude protein content (151.2 g/kg DM). Leaves of Searsia lancea species that were harvested from both the clay-loamy and red-brown sandy soils had the highest (P <0.05) amounts of condensed tannins (0.915 AU550/200 mg and 0.917 AU550/200 mg, respectively). Searsia lancea leaves had the lowest (P <0.05) in vitro ruminal nitrogen degradability values in both soil types. The leaves of Z. mucronata and G. flava leaves have potential as protein supplements for ruminants owing to their higher crude protein content and in vitro ruminal N degradability. Keywords: canopy cover, feeding value, plant height, semi-arid, species diversity, tree equivalent

scholarly journals Variability of aggressiveness and virulence of Erwinia carotovora subsp. carotovorum causing the soft rot on potato tubers in the western of Algeria

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
M’hamed Benada ◽  
Boualem Boumaaza ◽  
Sofiane Boudalia ◽  
Omar Khaladi ◽  
Bettache Guessas
Keyword(s):  
Erwinia Carotovora ◽  
Soft Rot ◽  
In Vitro Tests ◽  
Potato Storage ◽  
Bacterial Isolates ◽  
Potato Tubers ◽  
Potato Plants ◽  
Set Up ◽  
Cultivar Susceptibility

Soft rot symptoms were observed on potato plants in several potato cultivars in the western part of Algeria. A total of four strains of Erwinia are devided as follow: i) three strains of bacteria isolated from diseased tissues and soil, identified as Erwinia carotovora subsp carotovorum using conventional bacteriological and biochemical methods; and ii) one strain as Erwinia sp, not pathogens. In vitro tests, on tuber slices were set up to determine slices weight lost, which allows to find differences in cultivar susceptibility and isolate aggressiveness. Among the five cultivars, Laura was the most susceptible than the others tested cultivars. Moreover, it was found that MAI isolate was the most virulent than the other bacterial isolates. The results of this study should allow an optimization of the potato storage, after considering the susceptibility of a given cultivar to soft rot development and the aggressiveness.

scholarly journals Identification of epiphytic yeasts and bacteria with potential for biocontrol of grey mold disease on table grapes caused by Botrytis cinerea

2018 ◽  
Vol 16 (1) ◽  
pp. e1002 ◽  
Author(s):  
Kazem Kasfi ◽  
Parissa Taheri ◽  
Behrooz Jafarpour ◽  
Saeed Tarighi
Keyword(s):  
Botrytis Cinerea ◽  
Disease Incidence ◽  
Gray Mold ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Bacterial Isolates ◽  
Thompson Seedless ◽  
Grape Berries ◽  
Table Grapes

The objective of this study was to identify grapevine epiphytic yeasts and bacteria for biocontrol of Botrytis cinerea on grapes. Antagonistic yeasts and bacteria were isolated from the epiphytic flora associated with grape berries and leaves cv. ‘Thompson seedless’ from vineyards in Iran and identified by sequencing the conserved genomic regions. A total of 130 yeast and bacterial isolates from the surface of grapevine were screened in vitro for determining their antagonistic effect against B. cinerea and used to control postharvest gray mold. Among the 130 isolates, five yeasts and four bacterial isolates showed the greatest antagonistic activity in vitro against B. cinerea. Two yeasts species including Meyerozyma guilliermondii and Candida membranifaciens had high antagonistic capability against the pathogen. Also, 4 bacterial isolates belonging to Bacillus sp. and Ralstonia sp. showed significant biocontrol effect against B. cinerea. The isolates were capable of producing volatile and non-volatile substances, which suppressed the pathogen growth. The antagonistic activity of selected yeasts and bacteria against the pathogen was investigated on wounded berries of ‘Thompson seedless’. On small clusters with intact berries, all of the antagonistic isolates considerably reduced the decay on grape berries and inhibition of gray mold incidence on fruits treated by these isolates was less than 50%, except for the isolate N1, which had higher capability in inhibiting the disease incidence. These results suggest that antagonist yeasts and bacteria with potential to control B. cinerea on grape can be found in the microflora of grape berries and leaves.

scholarly journals Isolation and evaluation of rhizobacteria against Ralstonia solanacearum the incitant of bacterial wilt of tomato

2020 ◽  
Vol 13 (2) ◽  
pp. 195-199
Author(s):  
C.S. Karibasappa ◽  
Yogendra Singh
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Inhibition Zone ◽  
Crop Plants ◽  
The Novel ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Biocontrol Activity ◽  
Highly Effective

Bacterial wilt caused by Ralstonia solanacearum is the world’s most economically important destructive disease of crop plants. In the current study, we aimed to evaluate the novel bacterial isolates from tomato rhizosphere for biocontrol of Ralstonia solanacearum. One eighty bacterial strains were isolated from the tomato rhizosperic soils collected from different regions of Uttarakhand state and evaluated for their biocontrol activity against R. solanacearum under in vitro conditions. Among them, six isolates were found to be highly effective in inhibiting the growth of R. solanacearum. The isolate GP2NA8 produced the highest inhibition zone followed by that of GP1NA2 and GP3NA6.

scholarly journals Identification of the Endophytic Bacterial Isolates and their in vitro and in vivo Antagonism against Ralstonia solanacearum

10.5109/4583 ◽  
2004 ◽  
Vol 49 (2) ◽  
pp. 233-241 ◽  
Author(s):  
Hoang Hoa Long ◽  
Naruto Furuya ◽  
Ichinari Yamamoto ◽  
Minoru Takeshita ◽  
Yoichi Takanami ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Bacterial Isolates

Extracellular protease from Bacillus subtilis B315 with antagonistic activity against bacterial wilt pathogen (Ralstonia solanacearum) of chili

2021 ◽  
Vol 22 (3) ◽  
Author(s):  
Nur Prihatiningsih ◽  
ARI ASNANI ◽  
HERU ADI DJATMIKO
Keyword(s):  
Bacillus Subtilis ◽  
Crude Extract ◽  
Incubation Time ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Antagonistic Activity ◽  
Extracellular Protease ◽  
Antagonistic Bacteria ◽  
Clear Zone

Abstract. Prihatiningsih N, Asnani A, Djatmiko HA. 2021. Extracellular protease from Bacillus subtilis B315 with antagonistic activity against bacterial wilt pathogen (Ralstonia solanacearum) of chili.  Biodiversitas 22: 1291-1295. Antagonistic bacteria isolated from a healthy potato are potential biocontrol agents against a number of bacterial pathogens. The capability of antagonistic bacteria to produce extracellular protease could be considered as an indicator of their antagonistic capacity. The objective of this research was to study the optimum activity of protease produced by Bacillus subtilis B315 to control Ralstonia solanacearum causing wilt of chili. In this research were optimum incubation time, pH and crude extract protease concentration of B. subtilis B315 examined for maximum production of extracellular protease. The results showed that B. subtilis B315 was capable of producing protease at optimum incubation time of 30 min, pH 9, and crude extract protease concentration 0.50% with an activity of 1.3185 U/mL. Protease-producing capability of B. subtilis B315 was shown by the formation of a clear zone around the colony of B. subtilis B315 grown on skim-milk agar medium. B. subtilis B315 was capable of inhibiting the growth of R. solanacearum in vitro as indicated by 32 mm clear zone. Furthermore, in chili application of B subtilis showed that this bacteria was capable of controlling chili bacterial wilt caused by R. solanacearum with effectiveness of 60.89%. The prospective of B. subtilis B315 could be formulated as biopesticide.

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