This study identified the phenotypic and genotypic characteristics of the bacteria that nodulate wild Lathyrus and Vicia species natural distribution in the Gaziantep province of Turkey. Principle component analysis of phenotypic features revealed that rhizobial isolates were highly resistant to stress factors such as high salt, pH and temperature. They were found to be highly sensitive to the concentrations (mg/mL) of the antibiotics neomycin 10, kanamycin, and tetracycline 5, as well as the heavy metals Ni 10, and Cu 10, and 5. As a result of REP-PCR analysis, it was determined that the rhizobial isolates were quite diverse, and 5 main groups and many subgroups being found. All of the isolates nodulating wild Vicia species were found to be related to Rhizobium sp., and these isolates were found to be in Clades II, III, IV, and V of the phylogenetic tree based on 16S rRNA. The isolates that nodulated wild Lathyrus species were in Clades I, II, IV, V, VI, VII, and VIII, and they were closely related to Rhizobium leguminasorum, Rhizobium sp., Phyllobacterium sp., Serratia sp., and Pseudomonas sp. According to the genetic analyses, the isolates could not be classified at the species level, the similarity ratio was low, they formed a distinct group that was supported by strong bootstrap values in the phylogenetic tree, and the differences discovered in the network analysis revealed the diversity among the isolates and gave important findings that these isolates may be new species.
- Klíčová slova
- Rhizobium, 16S rRNA, Diversity, Nodulation, Wild legumes,
- MeSH
- antibakteriální látky farmakologie MeSH
- Bacteria genetika klasifikace izolace a purifikace účinky léků MeSH
- DNA bakterií genetika MeSH
- fenotyp MeSH
- fylogeneze * MeSH
- genetická variace MeSH
- genotyp * MeSH
- kořenové hlízky rostlin * mikrobiologie MeSH
- Lathyrus * mikrobiologie MeSH
- Rhizobium genetika klasifikace izolace a purifikace MeSH
- RNA ribozomální 16S * genetika MeSH
- těžké kovy MeSH
- vikev * mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Turecko MeSH
- Názvy látek
- antibakteriální látky MeSH
- DNA bakterií MeSH
- RNA ribozomální 16S * MeSH
- těžké kovy MeSH
Legumes enter into symbiotic associations with soil nitrogen-fixing rhizobia, culminating in the creation of new organs, root nodules. This complex process relies on chemical and physical interaction between legumes and rhizobia, including early signalling events informing the host legume plant of a potentially beneficial microbe and triggering the nodulation program. The great significance of this plant-microbe interaction rests upon conversion of atmospheric dinitrogen not accessible to plants into a biologically active form of ammonia available to plants. The plant cytoskeleton consists in a highly dynamic network and undergoes rapid remodelling upon sensing various developmental and environmental cues, including response to attachment, internalization, and accommodation of rhizobia in plant root and nodule cells. This dynamic nature is governed by cytoskeleton-associated proteins that modulate cytoskeletal behaviour depending on signal perception and transduction. Precisely localized cytoskeletal rearrangements are therefore essential for the uptake of rhizobia, their targeted delivery, and establishing beneficial root nodule symbiosis. This review summarizes current knowledge about rhizobia-dependent rearrangements and functions of the cytoskeleton in legume roots and nodules. General patterns and nodule type-, nodule stage-, and species-specific aspects of actin filaments and microtubules remodelling are discussed. Moreover, emerging evidence is provided about fine-tuning the root nodulation process through cytoskeleton-associated proteins. We also consider future perspectives on dynamic localization studies of the cytoskeleton during early symbiosis utilizing state of the art molecular and advanced microscopy approaches. Based on acquired detailed knowledge of the mutualistic interactions with microbes, these approaches could contribute to broader biotechnological crop improvement.
- Klíčová slova
- Actin filaments, Cytoskeleton, Legumes, Microtubules, Nodules, Rhizobia, Root hairs, Signalling, Symbiosis,
- MeSH
- cytoskelet MeSH
- Fabaceae * fyziologie MeSH
- mikrotubuly MeSH
- Rhizobium * fyziologie MeSH
- symbióza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Modern and industrialized agriculture enhanced farm output during the last few decades, but it became possible at the cost of agricultural sustainability. Industrialized agriculture focussed only on the increase in crop productivity and the technologies involved were supply-driven, where enough synthetic chemicals were applied and natural resources were overexploited with the erosion of genetic diversity and biodiversity. Nitrogen is an essential nutrient required for plant growth and development. Even though nitrogen is available in large quantities in the atmosphere, it cannot be utilized by plants directly with the only exception of legumes which have the unique ability to fix atmospheric nitrogen and the process is known as biological nitrogen fixation (BNF). Rhizobium, a group of gram-negative soil bacteria, helps in the formation of root nodules in legumes and takes part in the BNF. The BNF has great significance in agriculture as it acts as a fertility restorer in soil. Continuous cereal-cereal cropping system, which is predominant in a major part of the world, often results in a decline in soil fertility, while legumes add nitrogen and improve the availability of other nutrients too. In the present context of the declining trend of the yield of some important crops and cropping systems, it is the need of the hour for enriching soil health to achieve agricultural sustainability, where Rhizobium can play a magnificent role. Though the role of Rhizobium in biological nitrogen fixation is well documented, their behaviour and performance in different agricultural environments need to be studied further for a better understanding. In the article, an attempt has been made to give an insight into the behaviour, performance and mode of action of different Rhizobium species and strains under versatile conditions.
- MeSH
- dusík analýza MeSH
- Fabaceae * mikrobiologie MeSH
- fixace dusíku MeSH
- klimatické změny MeSH
- pěstování plodin MeSH
- půda MeSH
- Rhizobium * genetika MeSH
- zelenina MeSH
- zemědělství MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- dusík MeSH
- půda MeSH
Growing evidence has highlighted the essential role of plant hormones, notably, cytokinins (CKs), in nitrogen-fixing symbiosis, both at early and late nodulation stages1,2. Despite numerous studies showing the central role of CK in nodulation, the importance of CK transport in the symbiosis is unknown. Here, we show the role of ABCG56, a full-size ATP-binding cassette (ABC) transporter in the early stages of the nodulation. MtABCG56 is expressed in roots and nodules and its messenger RNA levels increase upon treatment with symbiotic bacteria, isolated Nod factor and CKs, accumulating within the epidermis and root cortex. MtABCG56 exports bioactive CKs in an ATP-dependent manner over the plasma membrane and its disruption results in an impairment of nodulation. Our data indicate that ABCG-mediated cytokinin transport is important for proper establishment of N-fixing nodules.
- MeSH
- ABC transportér, podrodina G genetika metabolismus MeSH
- biologický transport MeSH
- cytokininy metabolismus MeSH
- fixace dusíku MeSH
- Medicago truncatula genetika mikrobiologie MeSH
- regulátory růstu rostlin metabolismus MeSH
- Rhizobium fyziologie MeSH
- rostlinné proteiny genetika metabolismus MeSH
- symbióza genetika MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- ABC transportér, podrodina G MeSH
- cytokininy MeSH
- regulátory růstu rostlin MeSH
- rostlinné proteiny MeSH
Fabeae legumes such as pea and faba bean form symbiotic nodules with a large diversity of soil Rhizobium leguminosarum symbiovar viciae (Rlv) bacteria. However, bacteria competitive to form root nodules (CFN) are generally not the most efficient to fix dinitrogen, resulting in a decrease in legume crop yields. Here, we investigate differential selection by host plants on the diversity of Rlv. A large collection of Rlv was collected by nodule trapping with pea and faba bean from soils at five European sites. Representative genomes were sequenced. In parallel, diversity and abundance of Rlv were estimated directly in these soils using metabarcoding. The CFN of isolates was measured with both legume hosts. Pea/faba bean CFN were associated to Rlv genomic regions. Variations of bacterial pea and/or faba bean CFN explained the differential abundance of Rlv genotypes in pea and faba bean nodules. No evidence was found for genetic association between CFN and variations in the core genome, but variations in specific regions of the nod locus, as well as in other plasmid loci, were associated with differences in CFN. These findings shed light on the genetic control of CFN in Rlv and emphasise the importance of host plants in controlling Rhizobium diversity.
- Klíčová slova
- Pisum sativum, Vicia faba, Rhizobium leguminosarum symbiovar viciae, competitiveness, genospecies, nod genes, nodules, symbiosis,
- MeSH
- fylogeneze MeSH
- Rhizobium leguminosarum * genetika MeSH
- Rhizobium * MeSH
- symbióza MeSH
- Vicia faba * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Plant-rhizobia symbiosis can activate key genes involved in regulating nodulation associated with biological nitrogen fixation (BNF). Although the general molecular basis of the BNF process is frequently studied, little is known about its intraspecific variability and the characteristics of its allelic variants. This study's main goals were to describe phenotypic and genotypic variation in the context of nitrogen fixation in red clover (Trifolium pretense L.) and identify variants in BNF candidate genes associated with BNF efficiency. Acetylene reduction assay validation was the criterion for selecting individual plants with particular BNF rates. Sequences in 86 key candidate genes were obtained by hybridization-based sequence capture target enrichment of plants with alternative phenotypes for nitrogen fixation. Two genes associated with BNF were identified: ethylene response factor required for nodule differentiation (EFD) and molybdate transporter 1 (MOT1). In addition, whole-genome population genotyping by double-digest restriction-site-associated sequencing (ddRADseq) was performed, and BNF was evaluated by the natural 15N abundance method. Polymorphisms associated with BNF and reflecting phenotype variability were identified. The genetic structure of plant accessions was not linked to BNF rate of measured plants. Knowledge of the genetic variation within BNF candidate genes and the characteristics of genetic variants will be beneficial in molecular diagnostics and breeding of red clover.
- Klíčová slova
- associated genes, associated polymorphisms, biological nitrogen fixation, genome-wide association, red clover,
- MeSH
- alely MeSH
- fenotyp MeSH
- fixace dusíku genetika MeSH
- genotyp MeSH
- interakce mikroorganismu a hostitele MeSH
- kořeny rostlin genetika mikrobiologie MeSH
- polymorfismus genetický * MeSH
- Rhizobium fyziologie MeSH
- rostlinné geny genetika MeSH
- sekvenční analýza DNA metody MeSH
- symbióza genetika MeSH
- Trifolium genetika mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
The growing interest in a healthy lifestyle and in environmental protection is changing habits regarding food consumption and agricultural practices. Good agricultural practice is indispensable, particularly for raw vegetables, and can include the use of plant probiotic bacteria for the purpose of biofertilization. In this work we analysed the probiotic potential of the rhizobial strain PEPV40, identified as Rhizobium laguerreae through the analysis of the recA and atpD genes, on the growth of spinach plants. This strain presents several in vitro plant growth promotion mechanisms, such as phosphate solubilisation and the production of indole acetic acid and siderophores. The strain PEPV40 produces cellulose and forms biofilms on abiotic surfaces. GFP labelling of this strain showed that PEPV40 colonizes the roots of spinach plants, forming microcolonies typical of biofilm initiation. Inoculation with this strain significantly increases several vegetative parameters such as leaf number, size and weight, as well as chlorophyll and nitrogen contents. Therefore, our findings indicate, for the first time, that Rhizobium laguerreae is an excellent plant probiotic, which increases the yield and quality of spinach, a vegetable that is increasingly being consumed raw worldwide.
- MeSH
- biofilmy MeSH
- celulosa biosyntéza MeSH
- fenotyp MeSH
- fylogeneze MeSH
- kořeny rostlin mikrobiologie MeSH
- probiotika * MeSH
- Rhizobium klasifikace fyziologie MeSH
- semenáček mikrobiologie MeSH
- Spinacia oleracea růst a vývoj mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- celulosa MeSH
Rhizobia are a group of organisms that are well known for their ability to colonize root surfaces and form symbiotic associations with legume plants. They not only play a major role in biological nitrogen fixation but also improve plant growth and reduce disease incidence in various crops. Rhizobia are known to control the growth of many soilborne plant pathogenic fungi belonging to different genera like Fusarium, Rhizoctonia, Sclerotium, and Macrophomina. Antagonistic activity of rhizobia is mainly attributed to production of antibiotics, hydrocyanic acid (HCN), mycolytic enzymes, and siderophore under iron limiting conditions. Rhizobia are also reported to induce systemic resistance and enhance expression of plant defense-related genes, which effectively immunize the plants against pathogens. Seed bacterization with appropriate rhizobial strain leads to elicitation and accumulation of phenolic compounds, isoflavonoid phytoalexins, and activation of enzymes like L-phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), peroxidase (POX), polyphenol oxidase (PPO), and others involved in phenylpropanoid and isoflavonoid pathways. Development of Rhizobium inoculants with dual attributes of nitrogen fixation and antagonism against phytopathogens can contribute to increased plant growth and productivity. This compilation aims to bring together the available information on the biocontrol facet of rhizobia and identify research gaps and effective strategies for future research in this area.
In this study electrophoretic and mass spectrometric analysis of three types of bacterial sample (intact cells, cell lysates, and "washed pellets") were used to develop an effective procedure for the characterization of bacteria. The samples were prepared from specific bacterial strains. Five strains representing different species of the family Rhizobiaceae were selected as model microorganisms: Rhizobium leguminosarum bv. trifolii, R. leguminosarum bv. viciae, R. galegae, R. loti, and Sinorhizobium meliloti. Samples of bacteria were subjected to analysis by four techniques: capillary zone electrophoresis (CZE), capillary isoelectric focusing (CIEF), gel IEF, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). These methods are potential alternatives to DNA-based methods for rapid and reliable characterization of bacteria. Capillary electrophoretic (CZE and CIEF) analysis of intact cells was suitable for characterization of different bacterial species. CIEF fingerprints of "washed pellets" and gel IEF of cell lysates helped to distinguish between closely related bacterial species that were not sufficiently differentiated by capillary electrophoretic analysis of intact cells. MALDI-TOF MS of "washed pellets" enabled more reliable characterization of bacteria than analysis of intact cells or cell lysates. Electrophoretic techniques and MALDI-TOF MS can both be successfully used to complement standard methods for rapid characterization of bacteria.
- MeSH
- elektroforéza kapilární metody MeSH
- isoelektrická fokusace metody MeSH
- mikrobiální viabilita MeSH
- Rhizobium chemie klasifikace izolace a purifikace MeSH
- Sinorhizobium meliloti chemie klasifikace izolace a purifikace MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
The root nodules of Phaseolus mungo (a herbaceous leguminous pulse) contained a high amount of 3-indolylacetic acid (IAA). A tryptophan pool present in the nodule might play the role of precursor for IAA production. From the root nodule a Rhizobium sp. was isolated. The symbiont produced a large amount of IAA (142 microg/mL) from L-tryptophan-supplemented basal medium. The production of IAA by the symbiont was much increased over the control when a L-tryptophan (2 mg/mL) supplemented C-free mineral medium was enriched with mannitol (1 %), L-asparagine (0.3 %) and thiamine hydrochloride (1 microg/mL). The possible role of the rhizobial production of IAA on the rhizobia-legume symbiosis is discussed.
- MeSH
- fazol metabolismus mikrobiologie MeSH
- kořenové hlízky rostlin metabolismus mikrobiologie MeSH
- kultivační média metabolismus MeSH
- kyseliny indoloctové metabolismus MeSH
- Rhizobium růst a vývoj izolace a purifikace metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- kultivační média MeSH
- kyseliny indoloctové MeSH
