scholarly journals Priming of Plant Growth Promotion by Volatiles of Root-AssociatedMicrobacteriumspp.

2018 ◽  
Vol 84 (22) ◽  
Author(s):  
Viviane Cordovez ◽  
Sharella Schop ◽  
Kees Hordijk ◽  
Hervé Dupré de Boulois ◽  
Filip Coppens ◽  
...  

ABSTRACTVolatile compounds produced by plant-associated microorganisms represent a diverse resource to promote plant growth and health. Here, we investigated the effect of volatiles from root-associatedMicrobacteriumspecies on plant growth and development. Volatiles of eight strains induced significant increases in shoot and root biomass ofArabidopsisbut differed in their effects on root architecture.Microbacteriumstrain EC8 also enhanced root and shoot biomass of lettuce and tomato. Biomass increases were also observed for plants exposed only briefly to volatiles from EC8 prior to transplantation of the seedlings to soil. These results indicate that volatiles from EC8 can prime plants for growth promotion without direct and prolonged contact. We further showed that the induction of plant growth promotion is tissue specific; that is, exposure of roots to volatiles from EC8 led to an increase in plant biomass, whereas shoot exposure resulted in no or less growth promotion. Gas chromatography–quadrupole time of flight mass spectometry (GC–QTOF-MS) analysis revealed that EC8 produces a wide array of sulfur-containing compounds, as well as ketones. Bioassays with synthetic sulfur volatile compounds revealed that the plant growth response to dimethyl trisulfide was concentration-dependent, with a significant increase in shoot weight at 1 μM and negative effects on plant biomass at concentrations higher than 1 mM. Genome-wide transcriptome analysis of volatile-exposedArabidopsisseedlings showed upregulation of genes involved in assimilation and transport of sulfate and nitrate. Collectively, these results show that root-associatedMicrobacteriumprimes plants, via the roots, for growth promotion, most likely via modulation of sulfur and nitrogen metabolism.IMPORTANCEIn the past decade, various studies have described the effects of microbial volatiles on other (micro)organismsin vitro, but their broad-spectrum activityin vivoand the mechanisms underlying volatile-mediated plant growth promotion have not been addressed in detail. Here, we revealed that volatiles from root-associated bacteria of the genusMicrobacteriumcan enhance the growth of different plant species and can prime plants for growth promotion without direct and prolonged contact between the bacterium and the plant. Collectively, these results provide new opportunities for sustainable agriculture and horticulture by exposing roots of plants only briefly to a specific blend of microbial volatile compounds prior to transplantation of the seedlings to the greenhouse or field. This strategy has no need for large-scale introduction or root colonization and survival of the microbial inoculant.

2021 ◽  
Vol 11 ◽  
Author(s):  
Francisco Massot ◽  
Panagiotis Gkorezis ◽  
Jonathan Van Hamme ◽  
Damian Marino ◽  
Bojana Spirovic Trifunovic ◽  
...  

The large-scale use of the herbicide glyphosate leads to growing ecotoxicological and human health concerns. Microbe-assisted phytoremediation arises as a good option to remove, contain, or degrade glyphosate from soils and waterbodies, and thus avoid further spreading to non-target areas. To achieve this, availability of plant-colonizing, glyphosate-tolerant and -degrading strains is required and at the same time, it must be linked to plant-microorganism interaction studies focusing on a substantive ability to colonize the roots and degrade or transform the herbicide. In this work, we isolated bacteria from a chronically glyphosate-exposed site in Argentina, evaluated their glyphosate tolerance using the minimum inhibitory concentration assay, their in vitro degradation potential, their plant growth-promotion traits, and performed whole genome sequencing to gain insight into the application of a phytoremediation strategy to remediate glyphosate contaminated agronomic soils. Twenty-four soil and root-associated bacterial strains were isolated. Sixteen could grow using glyphosate as the sole source of phosphorous. As shown in MIC assay, some strains tolerated up to 10000 mg kg–1 of glyphosate. Most of them also demonstrated a diverse spectrum of in vitro plant growth-promotion traits, confirmed in their genome sequences. Two representative isolates were studied for their root colonization. An isolate of Ochrobactrum haematophilum exhibited different colonization patterns in the rhizoplane compared to an isolate of Rhizobium sp. Both strains were able to metabolize almost 50% of the original glyphosate concentration of 50 mg l–1 in 9 days. In a microcosms experiment with Lotus corniculatus L, O. haematophilum performed better than Rhizobium, with 97% of glyphosate transformed after 20 days. The results suggest that L. corniculatus in combination with to O. haematophilum can be adopted for phytoremediation of glyphosate on agricultural soils. An effective strategy is presented of linking the experimental data from the isolation of tolerant bacteria with performing plant-bacteria interaction tests to demonstrate positive effects on the removal of glyphosate from soils.


Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 682
Author(s):  
Bruno Henrique Silva Dias ◽  
Sung-Hee Jung ◽  
Juliana Velasco de Castro Oliveira ◽  
Choong-Min Ryu

Plant growth-promoting rhizobacteria (PGPR) associated with plant roots can trigger plant growth promotion and induced systemic resistance. Several bacterial determinants including cell-wall components and secreted compounds have been identified to date. Here, we review a group of low-molecular-weight volatile compounds released by PGPR, which improve plant health, mostly by protecting plants against pathogen attack under greenhouse and field conditions. We particularly focus on C4 bacterial volatile compounds (BVCs), such as 2,3-butanediol and acetoin, which have been shown to activate the plant immune response and to promote plant growth at the molecular level as well as in large-scale field applications. We also disc/ uss the potential applications, metabolic engineering, and large-scale fermentation of C4 BVCs. The C4 bacterial volatiles act as airborne signals and therefore represent a new type of biocontrol agent. Further advances in the encapsulation procedure, together with the development of standards and guidelines, will promote the application of C4 volatiles in the field.


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

2017 ◽  
Vol 9 (3) ◽  
pp. 1310-1316
Author(s):  
Gurjot Kaur ◽  
Poonam Sharma ◽  
Deepika Chhabra ◽  
Kailash Chand ◽  
Gurjit Singh Mangat

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Francesca Mapelli ◽  
Ramona Marasco ◽  
Eleonora Rolli ◽  
Marta Barbato ◽  
Hanene Cherif ◽  
...  

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.


2012 ◽  
Vol 194 (23) ◽  
pp. 6649-6650 ◽  
Author(s):  
Ju Yeon Song ◽  
Min-Jung Kwak ◽  
Kwang Youll Lee ◽  
Hyun Gi Kong ◽  
Byung Kwon Kim ◽  
...  

ABSTRACTBurkholderia pyrrociniaCH-67 was isolated from forest soil as a biocontrol agent to be utilized in agriculture. Here, we report the 8.05-Mb draft genome sequence of this bacterium. Its genome contains genes involved in biosynthesis of secondary metabolites and plant growth promotion, which may contribute to probiotic effects on plants.


2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Enock Mpofu ◽  
Felipe Vejarano ◽  
Chiho Suzuki-Minakuchi ◽  
Yoshiyuki Ohtsubo ◽  
Masataka Tsuda ◽  
...  

Bacillus licheniformis strain TAB7 degrades short-chain fatty acids responsible for offensive odor in manure and is used as a deodorant in a compost-deodorizing technology. Here, we report the complete genome sequence of strain TAB7, which consists of a 4.37-Mb chromosome and two plasmids (42 kb and 31 kb).


2016 ◽  
Vol 82 (6) ◽  
pp. 1734-1744 ◽  
Author(s):  
Yanmei Chen ◽  
Yuanqing Chao ◽  
Yaying Li ◽  
Qingqi Lin ◽  
Jun Bai ◽  
...  

ABSTRACTPlant-associated bacteria are of great interest because of their potential use in phytoremediation. However, their ability to survive and promote plant growth in metal-polluted soils remains unclear. In this study, a soilborne Cd-resistant bacterium was isolated and identified asEnterobactersp. strain EG16. It tolerates high external Cd concentrations (Cd2+MIC, >250 mg liter−1) and is able to produce siderophores and the plant hormone indole-3-acetic acid (IAA), both of which contribute to plant growth promotion. Surface biosorption in this strain accounted for 31% of the total Cd accumulated. The potential presence of cadmium sulfide, shown by energy-dispersive X-ray (EDX) analysis, suggested intracellular Cd binding as a Cd response mechanism of the isolate. Cd exposure resulted in global regulation at the transcriptomic level, with the bacterium switching to an energy-conserving mode by inhibiting energy-consuming processes while increasing the production of stress-related proteins. The stress response system included increased import of sulfur and iron, which become deficient under Cd stress, and the redirection of sulfur metabolism to the maintenance of intracellular glutathione levels in response to Cd toxicity. Increased production of siderophores, responding to Cd-induced Fe deficiency, not only is involved in the Cd stress response systems of EG16 but may also play an important role in promoting plant growth as well as alleviating the Cd-induced inhibition of IAA production. The newly isolated strain EG16 may be a suitable candidate for microbially assisted phytoremediation due to its high resistance to Cd and its Cd-induced siderophore production, which is likely to contribute to plant growth promotion.


Author(s):  
Di Fan ◽  
Donald L. Smith

There are pressing needs to reduce the use of agrochemicals, and PGPR are receiving increasing interest in plant growth promotion and disease protection. This study follows up our previous report that the four newly isolated rhizobacteria promote the growth of Arabidopsis thaliana .


2017 ◽  
Vol 4 (4) ◽  
pp. 464-469
Author(s):  
Sampada Mishra ◽  
Saroj Kumar Mahato ◽  
Sabin Basi ◽  
Shradha Basi-Chipalu

Minimization of deleterious effects of chemical fertilizers on health, ecosystem and economy can only be achieved by finding healthy, eco-friendly and cheap alternatives. Naturally selected symbiotic relationship between the endophytic bacteria and their host plants makes them an ideal candidate as biofertilizer. They can synthesize various plant growth hormones as well as assist their host in uptake of nutrients from soil.The study was designed to compare plant growth promotion of Solanum lycopersicum by Bacillus spp., Pseudomonas spp. and total endophytic community isolated from roots of S. lycopersicum, grown in the soil samples collected from various locations of Kathmandu valley of Nepal. Tomato seeds were inoculated with mixtures of eight endophytic strains of Bacillus spp. and Pseudomonas spp., and crude endophytes obtained from each location separately.Endophytic treatments, except Pseudomonas spp., inhibited seminal root growth during 12-days germination period. However, after plantation, root and shoot biomass was enhanced by the endophytes, with no significant differences among the bacterial treatments. The shoot height was also enhanced, among which Pseudomonas spp. had the strongest effect. In phosphate solubilization assay, out of seventy-two isolates each of Bacillus spp. and Pseudomonas spp. tested, twenty-four isolates of Pseudomonas spp. and sixteen isolates of Bacillus spp. could solubilize phosphate. Higher number of phosphate solubilizing isolates of Pseudomonas spp. might provide a possible explanation for the greater enhancement of shoot height by Pseudomonas spp. as compared to Bacillus spp.Int J Appl Sci Biotechnol, Vol 4(4): 464-469


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