scholarly journals Taxonomically Different Co-Microsymbionts of a Relict Legume, Oxytropis popoviana, Have Complementary Sets of Symbiotic Genes and Together Increase the Efficiency of Plant Nodulation

2018 ◽  
Vol 31 (8) ◽  
pp. 833-841 ◽  
Author(s):  
Vera I. Safronova ◽  
Andrey A. Belimov ◽  
Anna L. Sazanova ◽  
Elizaveta R. Chirak ◽  
Alla V. Verkhozina ◽  
...  
Keyword(s):  
Root Nodules ◽  
Housekeeping Genes ◽  
Nodule Formation ◽  
Symbiotic Genes ◽  
Internal Transcribed Spacer Region ◽  
Bradyrhizobium Sp ◽  
The Common ◽  
Different Strains ◽  
Slow Growing ◽  
Fix Genes

Ten rhizobial strains were isolated from root nodules of a relict legume Oxytropis popoviana Peschkova. For identification of the isolates, sequencing of rrs, the internal transcribed spacer region, and housekeeping genes recA, glnII, and rpoB was used. Nine fast-growing isolates were Mesorhizobium-related; eight strains were identified as M. japonicum and one isolate belonged to M. kowhaii. The only slow-growing isolate was identified as a Bradyrhizobium sp. Two strains, M. japonicum Opo-242 and Bradyrhizobium sp. strain Opo-243, were isolated from the same nodule. Symbiotic genes of these isolates were searched throughout the whole-genome sequences. The common nodABC genes and other symbiotic genes required for plant nodulation and nitrogen fixation were present in the isolate Opo-242. Strain Opo-243 did not contain the principal nod, nif, and fix genes; however, five genes (nodP, nodQ, nifL, nolK, and noeL) affecting the specificity of plant-rhizobia interactions but absent in isolate Opo-242 were detected. Strain Opo-243 could not induce nodules but significantly accelerated the root nodule formation after coinoculation with isolate Opo-242. Thus, we demonstrated that taxonomically different strains of the archaic symbiotic system can be co-microsymbionts infecting the same nodule and promoting the nodulation process due to complementary sets of symbiotic genes.

scholarly journals Rhizobial Synthesized Cytokinins Contribute to But Are Not Essential for the Symbiotic Interaction Between Photosynthetic Bradyrhizobia and Aeschynomene Legumes

2013 ◽  
Vol 26 (10) ◽  
pp. 1232-1238 ◽  
Author(s):  
Kateřina Podlešáková ◽  
Joel Fardoux ◽  
Delphine Patrel ◽  
Katia Bonaldi ◽  
Ondřej Novák ◽  
...  
Keyword(s):  
Root Nodules ◽  
Rna Degradation ◽  
Nodule Development ◽  
Nodule Formation ◽  
Symbiotic Interaction ◽  
Extracellular Medium ◽  
Exogenous Addition ◽  
Bradyrhizobium Sp ◽  
Derivatives Of

Cytokinins (CK) play an important role in the formation of nitrogen-fixing root nodules. It has been known for years that rhizobia secrete CK in the extracellular medium but whether they play a role in nodule formation is not known. We have examined this question using the photosynthetic Bradyrhizobium sp. strain ORS285 which is able to nodulate Aeschynomene afraspera and A. indica using a Nod-dependent or Nod-independent symbiotic process, respectively. CK profiling showed that the most abundant CK secreted by Bradyrhizobium sp. strain ORS285 are the 2MeS (2-methylthiol) derivatives of trans-zeatin and isopentenyladenine. In their pure form, these CK can activate legume CK receptors in vitro, and their exogenous addition induced nodule-like structures on host plants. Deletion of the miaA gene showed that transfer RNA degradation is the source of CK production in Bradyrhizobium sp. strain ORS285. In nodulation studies performed with A. indica and A. afraspera, the miaA mutant had a 1-day delay in nodulation and nitrogen fixation. Moreover, A. indica plants formed considerably smaller but more abundant nodules when inoculated with the miaA mutant. These data show that CK produced by Bradyrhizobium sp. strain ORS285 are not the key signal triggering nodule formation during the Nod-independent symbiosis but they contribute positively to nodule development in Aeschynomene plants.

scholarly journals Biodiversity and Geographic Distribution of Rhizobia Nodulating With Vigna minima

2021 ◽  
Vol 12 ◽  
Author(s):  
Guohua Liu ◽  
Xiaoling Liu ◽  
Wei Liu ◽  
Kangning Gao ◽  
Xiaoli Chen ◽  
...  
Keyword(s):  
Root Nodules ◽  
Housekeeping Genes ◽  
Symbiotic Genes ◽  
Sequence Analyses ◽  
Available Nitrogen ◽  
Shandong Peninsula ◽  
Factors Affecting ◽  
Nodulation Test ◽  
First Time ◽  
Vigna Minima

Vigna minima is a climbing annual plant widely distributed in barren wilderness, grass land, and shrub bush of China and other countries such as Japan. However, the rhizobia nodulating with this plant has never been systematically studied. In order to reveal the biodiversity of nodulating rhizobia symbiosis with V. minima, a total of 874 rhizobium isolates were obtained from root nodules of the plant spread in 11 sampling sites of Shandong Peninsula, China, and they were designated as 41 haplotypes in the genus Bradyrhizobium based upon recA sequence analyses. By multilocus sequence analysis (MLSA) of five housekeeping genes (dnaK, glnII, gyrB, recA, and rpoB), the 41 strains representing different recA haplotypes were classified into nine defined species and nine novel genospecies. Bradyrhizobium elkanii, Bradyrhizobium ferriligni, and Bradyrhizobium pachyrhizi were the predominant and universally distributed groups. The phylogeny of symbiotic genes of nodC and nifH showed similar topology and phylogenetic relationships, in which all the representative strains were classified into two clades grouped with strains nodulating with Vigna spp., demonstrating that Vigna spp. shared common nodulating groups in the natural environment. All the representative strains formed nodules with V. minima in a nodulation test performed in green house conditions. The correlation between V. minima nodulating rhizobia and soil characteristics analyzed by CANOCO indicates that available nitrogen, total nitrogen, and organic carbon in the soil samples were the main factors affecting the distribution of rhizobia isolated in this study. This study systematically uncovered the biodiversity and distribution characteristics of V. minima nodulating rhizobia for the first time, which provided novel information for the formation of the corresponding rhizobium community.

scholarly journals Bacterial Brown Pit, a New Disease of Edible Mushrooms Caused by Mycetocola sp.

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1445-1454
Author(s):  
Mozhde Hamidizade ◽  
S. Mohsen Taghavi ◽  
Samuel J. Martins ◽  
Rachel A. Herschlag ◽  
Kevin L. Hockett ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Agaricus Bisporus ◽  
Pathogenic Fungi ◽  
Housekeeping Genes ◽  
Edible Mushrooms ◽  
Bacterial Strains ◽  
Fusarium Spp ◽  
Button Mushroom ◽  
The Common ◽  
Slow Growing

From September to December 2018, commercial button mushroom (Agaricus bisporus) farms in central Iran were surveyed to monitor the causal agent(s) of browning and blotch symptoms on mushroom caps. In addition to dozens of pseudomonads (i.e., Pseudomonas tolaasii and Pseudomonas reactans), six slow-growing gram-positive bacterial strains were isolated from blotched mushroom caps. These bacteria presented as creamy white, circular, smooth, nonfluorescent, and shiny colonies with whole margins resembling members of Microbacteriaceae (Actinobacteria). All of the actinobacterial strains were aggressively pathogenic on cut cap surface of two edible mushrooms (i.e., A. bisporus and Pleurotus eryngii), inducing brown pit symptoms 48 h postinoculation. The strains did not induce symptoms on the vegetables tested (i.e., carrot, cucumber, and potato), and they did not affect the growth of mycelium of tested plant-pathogenic fungi (i.e., Acremonium sp., Fusarium spp., and Phytopythium sp.). Phylogeny of 16S ribosomal RNA and multilocus sequence analysis of six housekeeping genes (i.e., atpD, dnaK, gyrB, ppK, recA, and rpoB) revealed that the bacterial strains belong to the actinobacterial genus Mycetocola spp., whereas the species status of the strains remains undetermined. Mushroom-associated Mycetocola species were previously reported to be capable of detoxifying tolaasin, a toxin produced by P. tolaasii, whereas the strains isolated in this study did not show tolaasin detoxification activities. Altogether, this is the first report of a mushroom disease caused by an actinobacterial species, and “bacterial brown pit” was assigned as the common name of the disease.

scholarly journals Isolation and evaluation of endophytic bacteria from root nodules of Glycine max L. (Merr.) and their potential use as biofertilizers

2019 ◽  
Vol 17 (3) ◽  
pp. e1103
Author(s):  
Arely A. Vargas-Díaz ◽  
Ronald Ferrera-Cerrato ◽  
Hilda V. Silva-Rojas ◽  
Alejandro Alarcón
Keyword(s):  
Endophytic Bacteria ◽  
Biochemical Characterization ◽  
Cropping Systems ◽  
Root Nodules ◽  
Nodule Development ◽  
Nodule Formation ◽  
N Fixation ◽  
Tropical Regions ◽  
Bradyrhizobium Sp ◽  
Soybean Plants

Aim of study: To isolate and characterize endophytic bacteria inhabiting soybean root nodules collected from two tropical cropping systems in Mexico, and to evaluate the bacterial effects in soybean plants under controlled conditions.Area of study: The study was carried out at two locations (San Antonio Cayal and Nuevo Progreso municipalities) of Campeche State, Mexico.Material and methods: Two experimental stages were performed: 1) isolation, morphological and biochemical characterization, and molecular identification of endophytic bacteria from root-nodules of four soybean varieties grown at field conditions; and 2) evaluation of the effects of endophytic isolates on soybean growth and nodule development, and the effects of bacterial co-inoculation on soybean plants, under controlled conditions.Main results: Twenty-three endophytic bacteria were isolated from root nodules, and identified as Agrobacterium, Bradyrhizobium, Rhizobium, Ensifer, Massilia, Chryseobacterium, Enterobacter, Microbacterium, Serratia, and Xanthomonas. Under controlled conditions, Rhizobium sp. CPO4.13C or Agrobacterium tumefaciens CPO4.15C significantly increased the plant height (46% and 41%, respectively), whereas Bradyrhizobium sp. CPO4.24C promoted the nodule formation (36 nodules/plant). The co-inoculation of B. japonicum USDA110 and Bradyrhizobium sp. CPO4.24C enhanced plant growth, height (33.87 cm), root nodulation (69 nodules/plant) and N-fixation (3.10 µmol C2H4 h-1 plant-1) in comparison to the negative control.Research highlights:  Results suggest that the native Bradyrhizobium sp. CPO4.24C may be used as a biofertilizer directed to developing sustainable soybean cropping at tropical regions.

scholarly journals Rhizobial microsymbionts of the narrowly endemic Oxytropis species growing in Kamchatka possess a set of genes that are associated with T3SS and T6SS secretion systems and can affect the development of symbiosis

2020 ◽  
Author(s):  
P. Guro ◽  
V. Safronova ◽  
A. Sazanova ◽  
I. Kuznetsova ◽  
A. Belimov ◽  
...  
Keyword(s):  
Host Specificity ◽  
Root Nodules ◽  
Kamchatka Peninsula ◽  
Rrna Gene ◽  
Nitrogen Fixing ◽  
Symbiotic Genes ◽  
Secretion Systems ◽  
Legume Symbiosis ◽  
Microbe Interactions ◽  
Different Strains

A collection of rhizobial strains isolated from root nodules of the narrowly endemic legume species Oxytropis erecta, O. anadyrensis, O. kamtschatica and O. pumilio growing on the Kamchatka Peninsula (Russian Federation) was obtained. Analysis of the 16S rRNA gene sequence showed a significant diversity of isolates belonging to the families Rhizobiaceae (Rhizobium), Phyllobacteriaceae (Mesorhizobium, Phyllobacterium) and Bradyrhizobiaceae (Bosea, Tardiphaga). Pairs of taxonomically different strains in various combinations were isolated from some nodules of Oxytropis plants. Plant nodulation assays showed that only strains belonging to the genus Mesorhizobium (M. jarvisii, M. loti and M. huakuii) could form nitrogen-fixing nodules. The nitrogen-fixing activity of the strains was more associated with the host plant than with the species of strains. The whole genome sequences analysis showed that the strains M. loti 582 and M. huakuii 583 possessed symbiotic genes necessary for the formation of effective symbiosis and grouped into Sym-clusters. In contrast, the strain T. robiniae 581 had only a reduced number of fix genes, while the strains Phyllobacterium sp. 628 and R. lusitanum 629 possesed only individual symbiotic genes, which obviously did not participate in the formation of nodules. It was also stated that the strains M. loti 582 and M. huakuii 583 had a significantly larger set of genes related to the secretion systems T3SS and T6SS that can affect the host specificity of strains, compared with 6 commercial strains used as reference. These two strains formed nodules of two types (typical elongated and atypical rounded) on Oxytropis plants. We suggest that a possible cause of the observed phenomenon is the availability of different nodulation strategies in these strains (dependent and independent of Nod-factors). Thus, as a result of studying the collection of strains isolated from the narrow endemic species of Kamchatka Oxytropis, interesting objects were selected to study the functions of the T3SS and T6SS genes, and their role in the development of rhizobia-legume symbiosis. The prospects of using strains with gene systems for both symbiotic and non-symbiotic nodulation to enhance the efficiency of plant-microbe interactions by expanding the host specificity and increasing the efficiency of nodulation are discussed.

Ameloblastic Fibroma Associated With Impacted 3rd Molar: A Case Report

2017 ◽  
Vol 1 (7) ◽  
pp. 18-21
Author(s):  
K Indira Priyadarshini ◽  
Karthik Raghupathy ◽  
K V Lokesh ◽  
B Venu Naidu
Keyword(s):  
Relative Frequency ◽  
Posterior Region ◽  
Radiographic Examination ◽  
Dental Eruption ◽  
Ameloblastic Fibroma ◽  
Odontogenic Origin ◽  
The Common ◽  
The Times ◽  
The Right ◽  
Slow Growing

Ameloblastic fibroma is an uncommon mixed neoplasm of odontogenic origin with a relative frequency between 1.5 – 4.5%. It can occur either in the mandible or maxilla, but predominantly seen in the posterior region of the mandible. It occurs in the first two decades of life. Most of the times it is associated with tooth enclosure, causing a delay in eruption or altering the dental eruption sequence. The common clinical manifestation is a slow growing painless swelling and is detected during routine radiographic examination. There is controversy in the mode of treatment, whether conservative or aggressive. Here we reported a 38 year old male patient referred for evaluation of painless swelling on the right posterior region of the mandible associated with clinically missing 3rd molar. The lesion was completely enucleated under general anesthesia along with the extraction of impacted molar.

scholarly journals Rock-Solubilizing Microbial Inoculums Have Enormous Potential as Ecological Remediation Agents to Promote Plant Growth

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 357
Author(s):  
Zhaohui Jia ◽  
Miaojing Meng ◽  
Chong Li ◽  
Bo Zhang ◽  
Lu Zhai ◽  
...  
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Ecological Restoration ◽  
Root Nodules ◽  
Robinia Pseudoacacia ◽  
Growth Index ◽  
Nodule Formation ◽  
Bare Rock ◽  
Mining Sites ◽  
Robinia Pseudoacacia L

Anthropogenic overexploitation poses significant threats to the ecosystems that surround mining sites, which also have tremendous negative impacts on human health and society safety. The technological capacity of the ecological restoration of mine sites is imminent, however, it remains a challenge to sustain the green restorative effects of ecological reconstruction. As a promising and environmentally friendly method, the use of microbial technologies to improve existing ecological restoration strategies have shown to be effective. Nonetheless, research into the mechanisms and influences of rock-solubilizing microbial inoculums on plant growth is negligible and the lack of this knowledge inhibits the broader application of this technology. We compared the effects of rock-solubilizing microbial inoculums on two plant species. The results revealed that rock-solubilizing microbial inoculums significantly increased the number of nodules and the total nodule volume of Robinia pseudoacacia L. but not of Lespedeza bicolor Turcz. The reason of the opposite reactions is possibly because the growth of R. pseudoacacia was significantly correlated with nodule formation, whereas L. bicolor’s growth index was more closely related to soil characteristics and if soil nitrogen content was sufficient to support its growth. Further, we found that soil sucrase activity contributed the most to the height of R. pseudoacacia, and the total volume of root nodules contributed most to its ground diameter and leaf area. Differently, we found a high contribution of total soil carbon to seedling height and ground diameter of L. bicolor, and the soil phosphatase activity contributed the most to the L. bicolor’ s leaf area. Our work suggests that the addition of rock-solubilizing microbial inoculums can enhance the supply capacity of soil nutrients and the ability of plants to take up nutrients for the promotion of plant growth. Altogether, our study provides technical support for the practical application of rock-solubilizing microbes on bare rock in the future.

Effective and ineffective root nodules in Myrica faya

1976 ◽  
Vol 194 (1116) ◽  
pp. 285-293 ◽  
Keyword(s):  
Root Nodules ◽  
Light And Electron Microscopy ◽  
Nodule Formation ◽  
Culture Solution ◽  
Myrica Gale ◽  
Main Site ◽  
Myrica Faya ◽  
Modern Methods ◽  
Infected Cells ◽  
Nodule Endophytes

In cross-inoculation trials, inocula containing the nodule endophytes of Myrica gale, M. cerifera, M. cordifolia and M. pilulifera respectively were applied to the roots of young plants of M. faya Ait. growing in nitrogen-free culture solution. All four inocula induced nodule formation, and except where the M. gale inoculum had been used the nodules were of effective type and enabled the plants bearing them to grow nearly as well as other M. faya plants associated with the normal endophyte. The nodules induced by the M. gale endophyte were very numerous, but remained small and fixed no significant amount of nitrogen, and were thus ineffective. Light and electron microscopy showed that in the effective nodules induced by the normal endophyte or by that of M. cordifolia , the endophyte was confined to a layer 1-2 cells deep near the middle of the nodule cortex, and that in respect of the width of the hyphae and their production of club-shaped internally subdivided vesicles, the endophytes resembled closely those in the nodules of the few other species of Myrica that have been studied by modern methods of microscopy. In ineffective nodules the disposition of the infected cells was unchanged, but within the cells only a sparse development of the endophyte was observed, and no vesicles were found. The finding that nodules lacking vesicles showed little or no fixation is consistent with other evidence that the vesicles normally produced by non-legume nodule endophytes are the main site of nitrogen fixation.

Effects of a Nod-factor-overproducing strain of Sinorhizobium meliloti on the expression of the ENOD40 gene in Melilotus alba

2002 ◽  
Vol 80 (9) ◽  
pp. 907-915 ◽  
Author(s):  
Walter F Giordano ◽  
Michelle R Lum ◽  
Ann M Hirsch
Keyword(s):  
Lateral Root ◽  
Sinorhizobium Meliloti ◽  
Cortical Cell ◽  
Host Cells ◽  
Nodule Development ◽  
Nodule Formation ◽  
Additional Increase ◽  
Nod Factor ◽  
Melilotus Alba ◽  
Different Strains

We have initiated studies on the molecular biology and genetics of white sweetclover (Melilotus alba Desr.) and its responses to inoculation with the nitrogen-fixing symbiont Sinorhizobium meliloti. Early nodulin genes such as ENOD40 serve as markers for the transition from root to nodule development even before visible stages of nodule formation are evident. Using Northern blot analysis, we found that the ENOD40 gene was expressed within 6 h after inoculation with two different strains of S. meliloti, one of which overproduces symbiotic Nod factors. Inoculation with this strain resulted in an additional increase in ENOD40 gene expression over a typical wild-type S. meliloti strain. Moreover, the increase in mRNA brought about by the Nod-factor-overproducing strain 24 h after inoculation was correlated with lateral root formation by using whole-mount in situ hybridization to localize ENOD40 transcripts in lateral root meristems and by counting lateral root initiation sites. Cortical cell divisions were not detected. We also found that nodulation occurred more rapidly on white sweetclover in response to the Nod-factor-overproducing strain, but ultimately there was no difference in nodulation efficiency in terms of nodule number or the number of roots nodulated by the two strains. Also, the two strains could effectively co-colonize the host when inoculated together, although a few host cells were occupied by both strains.Key words: ENOD40, Nod factor, Melilotus, Sinorhizobium, symbiosis.

scholarly journals Development of Resistance to Hymexazol Among Pythium Species in Cucumber Greenhouses in Oman

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 202-208 ◽  
Author(s):  
Zainab M. Al-Balushi ◽  
Hesham Agrama ◽  
Issa H. Al-Mahmooli ◽  
Sajeewa S. N. Maharachchikumbura ◽  
Abdullah M. Al-Sadi
Keyword(s):  
Ribosomal Rna ◽  
Management Strategies ◽  
Soil Samples ◽  
Integrated Disease Management ◽  
Pythium Species ◽  
Internal Transcribed Spacer Region ◽  
Development Of Resistance ◽  
The Common ◽  
Cucumber Roots ◽  
Further Development

A study was conducted to characterize the common Pythium spp. in greenhouses in Oman and their level of resistance to hymexazol, a widely used fungicide in the country. Pythium isolates were obtained from soil samples, cocopeat bags, and cucumber roots collected from seven regions in the country. Identification of 80 Pythium isolates to the species level using sequences of the internal transcribed spacer region of the ribosomal RNA showed that they belong to four species: Pythium aphanidermatum (77 isolates), P. spinosum (1 isolate), P. myriotylum (1 isolate), and P. catenulatum (1 isolate). Investigating the aggressiveness of three Pythium spp. on cucumber showed that P. aphanidermatum, P. myriotylum, and P. spinosum are pathogenic. Phylogenetic analysis of P. aphanidermatum isolates showed that most of the isolates obtained from cocopeat clustered separately from isolates obtained from soil and roots. This may indicate a difference in the origin of the cocopeat isolates. Evaluating the resistance of 27 P. aphanidermatum isolates to hymexazol showed that most isolates were sensitive (0.9 to 31.2 mg liter−1) whereas one isolate was resistant (142.9 mg liter−1). This study is the first to report P. myriotylum and P. catenulatum in Oman. It is also the first to report the development of resistance to hymexazol among P. aphanidermatum populations from greenhouses. Growers should use integrated disease management strategies to avoid further development of resistance to hymexazol.

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