scholarly journals Endophytic Bacterial Isolates From Halophytes Demonstrate Phytopathogen Biocontrol and Plant Growth Promotion Under High Salinity

2021 ◽  
Vol 12 ◽  
Author(s):  
Christos A. Christakis ◽  
Georgia Daskalogiannis ◽  
Anastasia Chatzaki ◽  
Emmanouil A. Markakis ◽  
Glykeria Mermigka ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
High Salinity ◽  
Growth Promotion ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
In Planta ◽  
Promoting Effect ◽  
Cakile Maritima

Halophytic endophytes potentially contribute to the host’s adaptation to adverse environments, improving its tolerance against various biotic and abiotic stresses. Here, we identified the culturable endophytic bacteria of three crop wild relative (CWR) halophytes: Cakile maritima, Matthiola tricuspidata, and Crithmum maritimum. In the present study, the potential of these isolates to improve crop adaptations to various stresses was investigated, using both in vitro and in-planta approaches. Endophytic isolates were identified by their 16S rRNA gene sequence and evaluated for their ability to: grow in vitro in high levels of NaCl; inhibit the growth of the economically important phytopathogens Verticillium dahliae, Ralstonia solanacearum, and Clavibacter michiganensis and the human pathogen Aspergillus fumigatus; provide salt tolerance in-planta; and provide growth promoting effect in-planta. Genomes of selected isolates were sequenced. In total, 115 endophytic isolates were identified. At least 16 isolates demonstrated growth under increased salinity, plant growth promotion and phytopathogen antagonistic activity. Three showed in-planta suppression of Verticillium growth. Furthermore, representatives of three novel species were identified: two Pseudomonas species and one Arthrobacter. This study provides proof-of-concept that the endophytes from CWR halophytes can be used as “bio-inoculants,” for the enhancement of growth and stress tolerance in crops, including the high-salinity stress.

scholarly journals Genomic Analysis of the Endophytic Stenotrophomonas Strain 169 Reveals Features Related to Plant-Growth Promotion and Stress Tolerance

2021 ◽  
Vol 12 ◽  
Author(s):  
Kristina Ulrich ◽  
Michael Kube ◽  
Regina Becker ◽  
Volker Schneck ◽  
Andreas Ulrich
Keyword(s):  
Plant Growth ◽  
Stress Tolerance ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Whole Genome Sequence ◽  
Plant Colonization ◽  
Rrna Gene ◽  
Promote Plant Growth ◽  
Physiological Tests

Plant-associated Stenotrophomonas isolates have great potential for plant growth promotion, especially under stress conditions, due to their ability to promote tolerance to abiotic stresses such as salinity or drought. The endophytic strain Stenotrophomonas sp. 169, isolated from a field-grown poplar, increased the growth of inoculated in vitro plants, with a particular effect on root development, and was able to stimulate the rooting of poplar cuttings in the greenhouse. The strain produced high amounts of the plant growth-stimulating hormone auxin under in vitro conditions. The comparison of the 16S rRNA gene sequences and the phylogenetic analysis of the core genomes showed a close relationship to Stenotrophomonas chelatiphaga and a clear separation from Stenotrophomonas maltophilia. Whole genome sequence analysis revealed functional genes potentially associated with attachment and plant colonization, growth promotion, and stress protection. In detail, an extensive set of genes for twitching motility, chemotaxis, flagella biosynthesis, and the ability to form biofilms, which are connected with host plant colonization, could be identified in the genome of strain 169. The production of indole-3-acetic acid and the presence of genes for auxin biosynthesis pathways and the spermidine pathway could explain the ability to promote plant growth. Furthermore, the genome contained genes encoding for features related to the production of different osmoprotective molecules and enzymes mediating the regulation of stress tolerance and the ability of bacteria to quickly adapt to changing environments. Overall, the results of physiological tests and genome analysis demonstrated the capability of endophytic strain 169 to promote plant growth. In contrast to related species, strain 169 can be considered non-pathogenic and suitable for biotechnology applications.

scholarly journals Diazotrophic bacteria from maize exhibit multifaceted plant growth promotion traits in multiple hosts

2020 ◽  
Author(s):  
Shawn M. Higdon ◽  
Tania Pozzo ◽  
Emily J. Tibbett ◽  
Colleen Chiu ◽  
Richard Jeannotte ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Marker Genes ◽  
Diazotrophic Bacteria ◽  
In Planta ◽  
Pgp Traits

AbstractSierra Mixe maize is a geographically remote landrace variety grown on nitrogen-deficient fields in Oaxaca, Mexico that meets its nutritional requirements without synthetic fertilizer by associating with free-living diazotrophs comprising the microbiota of its aerial root mucilage. We selected nearly 500 diazotrophic bacteria isolated from Sierra Mixe maize mucilage and sequenced their genomes. Comparative genomic analysis demonstrated that isolates represented diverse genera and possessed multiple marker genes for mechanisms of direct plant growth promotion (PGP). In addition to nitrogen fixation, we examined deamination of 1-amino-1-cyclopropanecarboxylic acid, biosynthesis of indole-3-acetic acid, and phosphate solubilization. Implementing in vitro colorimetric assays revealed each isolate’s potential to confer the alternative PGP activities that corroborated genotype and pathway content. We examined the ability of mucilage diazotrophs to confer PGP by direct inoculation of clonally propagated potato plants in planta, which led to the identification of bio-stimulant candidates that were tested for PGP by inoculating a conventional maize variety. The results indicate that, while many diazotrophic isolates from Sierra Mixe maize possessed genotypes and in vitro phenotypes for targeted PGP traits, a subset of these organisms promoted the growth of potato and conventional maize using multiple promotion mechanisms.

scholarly journals Characterisation of Plant Growth-Promoting Endophytic Bacteria from Sugarcane and Their Antagonistic Activity against Fusarium moniliforme

2021 ◽  
Vol 32 (3) ◽  
pp. 97-118
Author(s):  
Nittaya Pitiwittayakul ◽  
Duanpen Wongsorn ◽  
Somboon Tanasupawat
Keyword(s):  
Plant Growth ◽  
Endophytic Bacteria ◽  
Fusarium Moniliforme ◽  
Growth Promotion ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Burkholderia Gladioli ◽  
Plant Growth Promoting ◽  
Chemical Usage

The use of endophytic bacteria in agriculture provides an effective way of improving crop yield and significantly reducing chemical usage, such as fungicides. This research was conducted to explore endophytic bacteria with plant growth promotion (PGP) and antifungal activities against Fusarium moniliforme AIT01. In this study, we obtained 52 isolates of endophytic bacteria associated with the roots and stems of sugarcane from Nakhon Ratchasima province, Thailand. In vitro antagonistic activity test showed that 14 out of 52 isolates had antagonistic activity against the fungal pathogen F. moniliforme AIT01. These antagonistic endophytic bacteria were identified as belonging to six different species as follows: Nguyenibacter vanlangensis, Acidomonas methanolica, Asaia bogorensis, Tanticharoenia aidae, Burkholderia gladioli and Bacillus altitudinis based on phenotypic characteristics, along with phylogenetic analysis of their 16S rRNA gene sequences. Seven isolates effectively inhibited F. moniliforme AIT01 mycelial growth by up to 40%. The volatile compounds of six isolates reduced the growth of F. moniliforme AIT01 by over 23%. Moreover, riceberry rice seedlings previously treated with B. gladioli CP28 were found to strongly reduce infection with phytopathogen by 80% in comparison to the non-treated control. Furthermore, the isolates also showed relevant PGP features, including ammonia production, zinc and phosphate solubilisation, auxin and siderophore biosynthesis. These results demonstrated that the tested endophytic bacteria could be successfully utilised as a source of PGP and biocontrol agent to manage diseases caused by F. moniliforme.

Effect of the endophytic plant growth promoting Enterobacter ludwigii EB4B on tomato growth

2020 ◽  
Vol 13 (2) ◽  
pp. 54-65 ◽  
Author(s):  
M.E.A. Bendaha ◽  
H.A. Belaouni
Keyword(s):  
Root Length ◽  
Biocontrol Agent ◽  
Growth Promotion ◽  
Dry Weight ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Plant Growth Promoting ◽  
Enterobacter Ludwigii ◽  
Tomato Growth

SummaryThis study aims to develop a biocontrol agent against Fusarium oxysporum f.sp. radicis-lycopersici (FORL) in tomato. For this, a set of 23 bacterial endophytic isolates has been screened for their ability to inhibit in vitro the growth of FORL using the dual plate assay. Three isolates with the most sound antagonistic activity to FORL have been qualitatively screened for siderophore production, phosphates solubilization and indolic acetic acid (IAA) synthesis as growth promotion traits. Antagonistic values of the three candidates against FORL were respectively: 51.51 % (EB4B), 51.18 % (EB22K) and 41.40 % (EB2A). Based on 16S rRNA gene sequence analysis, the isolates EB4B and EB22K were closely related to Enterobacter ludwigii EN-119, while the strain EB2A has been assigned to Leclercia adecarboxylata NBRC 102595. The promotion of tomato growth has been assessed in vitro using the strains EB2A, EB4B and EB22K in presence of the phytopathogen FORL. The treatments with the selected isolates increased significantly the root length and dry weight. Best results were observed in isolate EB4B in terms of growth promotion in the absence of FORL, improving 326.60 % of the root length and 142.70 % of plant dry weight if compared with untreated controls. In the presence of FORL, the strain EB4B improved both root length (180.81 %) and plant dry weight (202.15 %). These results encourage further characterization of the observed beneficial effect of Enterobacter sp. EB4B for a possible use as biofertilizer and biocontrol agent against FORL.

EFFICACY OF RHIZOBACTERIA ON PLANT GROWTH PROMOTION AND DISEASE SUPPRESSION IN VITRO

2012 ◽  
pp. 525-532 ◽  
Author(s):  
S. Velivelli ◽  
E. O'Herlihy ◽  
B. Janczura ◽  
B. Doyle Prestwich ◽  
J. Ghyselinck ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Disease Suppression

scholarly journals Exploitation of endophytic Pseudomonas sp. for plant growth promotion and colonization in rice

2017 ◽  
Vol 9 (3) ◽  
pp. 1310-1316
Author(s):  
Gurjot Kaur ◽  
Poonam Sharma ◽  
Deepika Chhabra ◽  
Kailash Chand ◽  
Gurjit Singh Mangat
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Acc Deaminase ◽  
Pseudomonas Sp ◽  
Bacterial Isolates ◽  
Pgp Traits ◽  
P Solubilization ◽  
Fluorescent Pigment

The present investigation was carried out to exploit bacterial endophytes associated with root and leaf tissue of rice plant for plant growth promotion (PGP) and colonization study in vitro. Total 10 endophytic bacterial isolates (Pseudomonas sp.) were evaluate for PGP traits like P solubilization, production of Indole acetic acid (IAA), siderophore, ACC deaminase, protease, cellulase, fluorescent pigment, urease and denitrification activity. Out of 10 endophytic bacteria 30 %, 60 %, 20 %, 70 %, 10 % and 10 % were positive for siderophore, protease, cellulase, fluorescent pigment, urease and denitrification respectively. Maximum IAA production was recorded with isolate LRBLE7 (18.8 μgml-1) followed by LRBRE4 (16.0 μgml-1) and maximum P-solubilization was recorded with isolate LRBRE4 (5.8 mg 100 ml-1) followed by LRBLE7 (4.4 mg 100 ml-1). ACC deaminase production was recorded with isolate LRBLE6 (O.D=0.352 nm) followed by LRBRE5 (O.D=0.324nm). Three potential isolates (LRBRE4, LRBRE6 and LRBLE7) were selected on the basis of multiple PGP traits and were subjected to colonization study of rice seedling in vitro. Potential bacterial isolates can be exploited for improving growth and productivity in rice under sustainable management system.

scholarly journals Potential for Plant Growth Promotion of Rhizobacteria Associated withSalicorniaGrowing in Tunisian Hypersaline Soils

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Francesca Mapelli ◽  
Ramona Marasco ◽  
Eleonora Rolli ◽  
Marta Barbato ◽  
Hanene Cherif ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Crop Production ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Growth Promotion ◽  
Arid Ecosystems ◽  
Acetic Acid Production ◽  
Halotolerant Bacteria ◽  
Microbiome Composition

Soil salinity and drought are among the environmental stresses that most severely affect plant growth and production around the world. In this study the rhizospheres ofSalicorniaplants and bulk soils were collected fromSebkhetandChotthypersaline ecosystems in Tunisia. Depiction of bacterial microbiome composition by Denaturing Gradient Gel Electrophoresis unveiled the occurrence of a high bacterial diversity associated withSalicorniaroot system. A large collection of 475 halophilic and halotolerant bacteria was established fromSalicorniarhizosphere and the surrounding bulk soil, and the bacteria were characterized for the resistance to temperature, osmotic and saline stresses, and plant growth promotion (PGP) features. TwentyHalomonasstrains showed resistance to a wide set of abiotic stresses and were able to perform different PGP activitiesin vitroat 5% NaCl, including ammonia and indole-3-acetic acid production, phosphate solubilisation, and potential nitrogen fixation. By using agfp-labelled strain it was possible to demonstrate thatHalomonasis capable of successfully colonisingSalicorniaroots in the laboratory conditions. Our results indicated that the culturable halophilic/halotolerant bacteria inhabiting salty and arid ecosystems have a potential to contribute to promoting plant growth under the harsh salinity and drought conditions. These halophilic/halotolerant strains could be exploited in biofertilizer formulates to sustain crop production in degraded and arid lands.

scholarly journals Plant Growth Promotion Potential Is Equally Represented in Diverse Grapevine Root-Associated Bacterial Communities from Different Biopedoclimatic Environments

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Ramona Marasco ◽  
Eleonora Rolli ◽  
Marco Fusi ◽  
Ameur Cherif ◽  
Ayman Abou-Hadid ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Plant Growth ◽  
Bacterial Communities ◽  
Growth Promotion ◽  
Rrna Gene ◽  
Similar Distribution ◽  
Bacterial Assemblage ◽  
Pgp Traits ◽  
Associated Bacteria

Plant-associated bacteria provide important services to host plants. Environmental factors such as cultivar type and pedoclimatic conditions contribute to shape their diversity. However, whether these environmental factors may influence the plant growth promoting (PGP) potential of the root-associated bacteria is not widely understood. To address this issue, the diversity and PGP potential of the bacterial assemblage associated with the grapevine root system of different cultivars in three Mediterranean environments along a macrotransect identifying an aridity gradient were assessed by culture-dependent and independent approaches. According to 16S rRNA gene PCR-DGGE, the structure of endosphere and rhizosphere bacterial communities was highly diverse (P=0.03) and was associated with a cultivar/latitudinal/climatic effect. Despite being diverse, the bacterial communities associated with Egyptian grapevines shared a higher similarity with the Tunisian grapevines than those cultivated in North Italy. A similar distribution, according to the cultivar/latitude/aridity gradients, was observed for the cultivable bacteria. Many isolates (23%) presentedin vitromultiple stress resistance capabilities and PGP activities, the most frequent being auxin synthesis (82%), insoluble phosphate solubilisation (61%), and ammonia production (70%). The comparable numbers and types of potential PGP traits among the three different environmental settings indicate a strong functional homeostasis of beneficial bacteria associated with grape root.

scholarly journals Arsenic-Redox Transformation and Plant Growth Promotion by Purple Nonsulfur Bacteria Rhodopseudomonas palustris CS2 and Rhodopseudomonas faecalis SS5

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Kanza Batool ◽  
Fatima tuz Zahra ◽  
Yasir Rehman
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Root Length ◽  
Growth Promotion ◽  
Rhodopseudomonas Palustris ◽  
Shoot Length ◽  
Rrna Gene ◽  
Purple Nonsulfur Bacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting

Arsenic (As) is a well-known toxic metalloid found naturally and released by different industries, especially in developing countries. Purple nonsulfur bacteria (PNSB) are known for wastewater treatment and plant growth promoting abilities. As-resistant PNSB were isolated from a fish pond. Based on As-resistance and plant growth promoting attributes, 2 isolates CS2 and SS5 were selected and identified as Rhodopseudomonas palustris and Rhodopseudomonas faecalis, respectively, through 16S rRNA gene sequencing. Maximum As(V) resistance shown by R. faecalis SS5 and R. palustris CS2 was up to 150 and 100 mM, respectively. R. palustris CS2 showed highest As(V) reduction up to 62.9% (6.29±0.24 mM), while R. faecalis SS5 showed maximum As(III) oxidation up to 96% (4.8±0.32 mM), respectively. Highest auxin production was observed by R. palustris CS2 and R. faecalis SS, up to 77.18±3.7 and 76.67±2.8 μg mL−1, respectively. Effects of these PNSB were tested on the growth of Vigna mungo plants. A statistically significant increase in growth was observed in plants inoculated with isolates compared to uninoculated plants, both in presence and in absence of As. R. palustris CS2 treated plants showed 17% (28.1±0.87 cm) increase in shoot length and 21.7% (7.07±0.42 cm) increase in root length, whereas R. faecalis SS5 treated plants showed 12.8% (27.09±0.81 cm) increase in shoot length and 18.8% (6.9±0.34 cm) increase in root length as compared to the control plants. In presence of As, R. palustris CS2 increased shoot length up to 26.3% (21.0±1.1 cm), while root length increased up to 31.3% (5.3±0.4 cm), whereas R. faecalis SS5 inoculated plants showed 25% (20.7 ± 1.4 cm) increase in shoot length and 33.3% (5.4 ± 0.65 cm) increase in root length as compared to the control plants. Bacteria with such diverse abilities could be ideal for plant growth promotion in As-contaminated sites.

scholarly journals Plant growth promoting rhizobacteria and their potential as bioinoculants on Pennisetum clandestinum (Poaceae)

2019 ◽  
Vol 67 (4) ◽  
Author(s):  
Felipe Romero-Perdomo ◽  
Jhonnatan Ocampo-Gallego ◽  
Mauricio Camelo-Rusinque ◽  
Ruth Bonila
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Dry Weight ◽  
Shoot Length ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Pennisetum Clandestinum ◽  
Shoot Dry Weight ◽  
Root And Shoot Length

In this study, we aimed at examining the potential to stimulate growth in Pennisetum clandestinum using four isolated bacterial strains from soils obtained from a Colombian tropical silvopastoral system. We previously identified genetically the strains and characterized two plant growth promotion activities. We found that the four bacterial strains were phylogenetically associated with Klebsiella sp. (strains 28P and 35P), Beijerinka sp. (37L) and Achromobacter xylosoxidans (E37), based on partial 16S rRNA gene sequencing. Moreover, the in vitro biochemical assays demonstrated that the strains exhibited some plant growth promotion mechanisms such as 1-aminocyclopropane-1-carboxylic acid deaminase activity and indole compound synthesis. Notably, bacterial inoculation under greenhouse conditions showed a positive influence on P. clandestinum growth. We found a significant (p < 0.05) effect on root and shoot length, and shoot dry weight. Shoot length increased by 52% and 30% with 37L and 35P, respectively, compared to those without inoculation treatment. Similarly, the use of 37L and 28P raised shoot dry weight values by 170% and 131%, respectively. In root development, inoculation with strains 37L and E37 increased root length by 134% and 100%, respectively. Beijerinckia sp. 37L was the most effective of the four strains at increasing P. clandestinum biomass and length.

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