scholarly journals Nitrogen Fixation by Paenibacillus Polymyxa WLY78 is Responsible for Cucumber Growth Promotion

2021 ◽  
Author(s):  
Shuang Liu ◽  
Qin Li ◽  
Yongbin Li ◽  
Tianyi Hao ◽  
Sanfeng Chen
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Gene Cluster ◽  
Isotope Dilution ◽  
Laser Scanning ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Confocal Laser ◽  
Greenhouse Experiments ◽  
Dilution Experiments

Abstract Aims To study nitrogen contribution to cucumber derived from nitrogen fixation of Paenibacillus polymyxa WLY78.Methods The nif gene cluster deletion mutant (ΔnifB-V) of P. polymyxa WLY78 is constructed by a homologous recombination method. The GFP-labeled ΔnifB-V mutant was used to inoculate cucumber and to study colonization by confocal laser scanning microscope. The effects of plant-growth promotion were investigated by greenhouse experiments. The nitrogen fixation contribution was estimated by 15N isotope dilution experiments. Results Deletion of nif gene cluster of P. polymyxa WLY78 resulted in complete loss of nitrogenase activity. Observation by laser confocal microscopy revealed ΔnifB-V mutant can effectively colonize cucumber root, stem and leaf tissues, like wild-type P. polymyxa WLY78. Greenhouse experiments showed that inoculation with P. polymyxa WLY78 can significantly enhance the lengths and dry weights of cucumber roots and shoots, but inoculation with ΔnifB-V mutant can not. 15N isotope dilution experiments showed that cucumber plants derive 25.93% nitrogen from nitrogen fixation performed by P. polymyxa WLY78, but the ΔnifB-V mutant nearly can not provide nitrogen for plant growth. Conclusions This present study demonstrates that nitrogen fixation performed by P. polymyxa WLY78 is responsible for cucumber growth promotion.

Comparison of Paenibacillus polymyxa wild-type and Nif− mutant in colonization, plant-growth promotion and nitrogen fixation contribution

2021 ◽  
Author(s):  
Shuang Liu ◽  
Qin Li ◽  
Yongbin Li ◽  
Tianyi Hao ◽  
Haowei Zhang ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Isotope Dilution ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Paenibacillus Polymyxa ◽  
Confocal Laser ◽  
Wild Type ◽  
Greenhouse Experiments ◽  
Dilution Experiments

Abstract Aims This study aimed to compare the effect on colonization, plant-growth promotion and nitrogen fixation contribution by inoculation with Paenibacillus polymyxa wild-type and Nif−mutant. Methods Paenibacillus polymyxa wild-type and Nif− mutant was labeled with GFP and then the GFP-labeled bacteria were used to inoculate cucumber. The colonization patterns of P. polymyxa WLY78 in these plants were observed under the confocal laser scanning microscope. The effects of plant-growth promotion were investigated by greenhouse experiments. The nitrogen fixation contribution was estimated by 15N isotope dilution experiments. Results Observation by laser confocal microscopy revealed that both P. polymyxa WLY78 and ΔnifB-V mutant can effectively colonize cucumber root, stem and leaf tissues. Greenhouse experiments showed that inoculation with P. polymyxa WLY78 can significantly enhance the lengths and fresh wights of cucumber roots and shoots, but inoculation with ΔnifB-V mutant can not. 15N isotope dilution experiments showed that cucumber plants derive 25.93% nitrogen from nitrogen fixation performed by P. polymyxa WLY78, but the ΔnifB-V mutant nearly can not provide nitrogen for plant. Conclusions This present study demonstrates that nitrogen fixation plays an import role in promoting plant growth.

scholarly journals Isolation and Characterization of Salt Tolerant Endophytic and Rhizospheric Plant Growth-Promoting Bacteria (PGPB) Associated with the Halophyte Plant (Sesuvium Verrucosum) Grown in KSA

2015 ◽  
Vol 3 (3) ◽  
pp. 552-560 ◽  
Author(s):  
Mohamed A.M. El-Awady ◽  
Mohamed M. Hassan ◽  
Yassin M. Al-Sodany
Keyword(s):  
Nitrogen Fixation ◽  
Acetic Acid ◽  
Plant Growth ◽  
Growth Promotion ◽  
Exponential Growth Phase ◽  
Plant Growth Promoting Bacteria ◽  
Salt Tolerant ◽  
Isolation And Characterization ◽  
Growth Promoting

This study was designed to isolate and characterize endophytic and rhizospheric bacteria associated with the halophyte plant Sesuvium verrucosum, grown under extreme salinity soil in Jeddah, Saudi Arabia. The plant growth promotion activities of isolated bacterial were evaluated in vitro. A total of 19 salt tolerant endophytic and rhizospheric bacterial isolates were obtained and grouped into six according to genetic similarity based on RAPD data. These six isolates were identified by amplification and partial sequences of 16S rDNA as Enterobacter cancerogenus,Vibrio cholerae, Bacillus subtilis, Escherichia coli and two Enterobacter sp. Isolates were then grown until exponential growth phase to evaluate the atmospheric nitrogen fixation, phosphate solubilization, and production of phytohormones such as indole-3-acetic acid, as well as 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. While, All of the six strains were negative for ACC deaminaseactivity, two isolates showed Nitrogen fixation activity, three isolates produce the plant hormone (Indole acetic acid) and two isolates have the activity of solubiliztion of organic phosphate. Among the six isolates, the isolate (R3) from the soil around the roots is able to perform the three previous growth promoting possibilities together and it is ideal for use in promoting the growth of plants under the high salinity conditions. This isolate is candidate to prepare a friendly biofertelizer that can be used for the improvement of the crops performance under salinity conditions.Int J Appl Sci Biotechnol, Vol 3(3): 552-560

scholarly journals SCREENING OF SOIL BACTERIA FOR PLANT GROWTH PROMOTION ACTIVITIES IN VITRO

2016 ◽  
Vol 4 (1) ◽  
pp. 27 ◽  
Author(s):  
Edi Husen
Keyword(s):  
Plant Growth ◽  
Soil Bacteria ◽  
Phosphate Solubilization ◽  
Azotobacter Vinelandii ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Chelating Agent ◽  
Plant Growth Promoting Rhizobacteria ◽  
Iaa Production

Fourteen isolates of soil bacteria, including two known plant growth promoting rhizobacteria (PGPR) strains, Azotobacter vinelandii Mac 259 and Bacillus cereus UW 85, were tested in vitro. Parameters assessed were indoleacetic acid (IAA) production, phosphate solubilization, dinitrogen fixation, and siderophore (Fe-III chelating agent) production. IAA production was assayed colorimetrically using ferric chlorideperchloric acid reagent. Phosphate-solubilization and siderophore production were tested qualitatively by plating the bacteria in Pikovskaya and chrome azurol S agar, respectively. The ability to fix dinitrogen was measured based on nitrogenase activity of the bacteria by gas chromatography. The results showed that twelve isolates produced IAA, ranged from 2.09 to 33.28 µmol ml-1. The ability to solubilize precipitated phosphate was positively exhibited by four isolates (BS 58, BTS, TCaR 61, and BTCaRe 65). Seven isolates including Mac 259 positively produced siderophore. None of the isolates showed nitrogenase activity. Only one isolate (TS 3) did not exhibit any of the traits tested. Isolate TCeRe 60 and reference strain Mac 259 were found to have IAA- and siderophore-producing traits. Four P-solubilizing bacteria (BS 58, BTS, TCaR 61, and BTCaRe 65) were also IAA- and siderophore-producing bacteria. Potential use of these PGPR isolates needs further test in enhancing plant growth.

scholarly journals Plant Growth Promoting Abilities of Novel Burkholderia-Related Genera and Their Interactions With Some Economically Important Tree Species

2021 ◽  
Vol 5 ◽  
Author(s):  
Munusamy Madhaiyan ◽  
Govindan Selvakumar ◽  
Tan HianHwee Alex ◽  
Lin Cai ◽  
Lianghui Ji
Keyword(s):  
Plant Growth ◽  
Oil Palm ◽  
Tree Species ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Acc Deaminase ◽  
Bacterial Strains ◽  
Pgp Traits ◽  
Plant Growth Promoting ◽  
Promote Plant Growth

A survey of bacterial endophytes associated with the leaves of oil palm and acacias resulted in the isolation of 19 bacterial strains belonging to the genera Paraburkholderia, Caballeronia, and Chitinasiproducens, which are now regarded as distinctively different from the parent genus Burkholderia. Most strains possessed one or more plant growth promotion (PGP) traits although nitrogenase activity was present in only a subset of the isolates. The diazotrophic Paraburkholderia tropica strain S39-2 with multiple PGP traits and the non-diazotrophic Chitinasiproducens palmae strain JS23T with a significant level of 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity were selected to investigate the influence of bacterial inoculation on some economically important tree species. Microscopic examination revealed that P. tropica S39-2 was rhizospheric as well as endophytic while C. palmae JS23T was endophytic. P. tropica strain S39-2 significantly promoted the growth of oil palm, eucalyptus, and Jatropha curcas. Interestingly, the non-diazotrophic, non-auxin producing C. palmae JS23T strain also significantly promoted the growth of oil palm and eucalyptus although it showed negligible effect on J. curcas. Our results suggest that strains belonging to the novel Burkholderia-related genera widely promote plant growth via both N-independent and N-dependent mechanisms. Our results also suggest that the induction of defense response may prevent the colonization of an endophyte in plants.

Bidirectional Selection for Nitrogenase Activity and Shoot Dry Weight Among Late Generation Progenies of a Virginia x Spanish Peanut Cross1

1986 ◽  
Vol 13 (2) ◽  
pp. 86-89 ◽  
Author(s):  
S. Arrendell ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Growth Habit ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Fruit Weight ◽  
Shoot Dry Weight ◽  
Plant Growth Habit ◽  
The Mean ◽  
Selection For

Abstract Improvement of the host contribution to nitrogen fixation has been proposed as a method of increasing nitrogen fixation. Significant variability and generally high broad-sense heritability estimates (.60 ± .27 to .82 ± .26 for nitrogenase activity and .53 ± .29 to .85 ± .26 for shoot dry weight) have been reported for F2-derived families from a cross between the Virginia (Arachis hypogaea L. ssp. hypogaea var. hypogaea) cultivar NC 6 and the Spanish (ssp. fastigiata Waldron vulgaris Harz.) breeding line 922, indicating selection for increased nigtogen fixation should be effective in this population. Lines from this population were chosen randomly from F2-derived families selected for high and low nitrogenase activity and high and low shoot dry weight after evaluation at three dates and two locations in each of 2 years (F5 and F6 generations). This study's objectives were to evaluate the N2-fixing ability of the selected lines and to evaluate the association between plant growth habit and N2 fixation. Twenty-four lines in each of the four selection groups and the parents, NC 6 and 922, were evaluated at two sampling dates and two locations. Mean nitrogenase activity of lines selected for increased nitrogenase activity was significantly greater than the mean of the lines selected for low nitrogenase activity. Improved nitrogenase activity was associated with increased fruit weight. The fruit weight mean of the group selected for increased fruit weight. The fruit weight mean of the group selected for increased nitrogenase activity was 39% greater than the mean of the group selected for low nitrogenase activity. Mean shoot dry weight of lines selected for increased shoot dry weight was significantly greater than the mean of the lines selected for low shoot dry weight; however, the fruit weight means of these two groups did not differ. It was hypothesized that selection for increased N2 fixation in a population derived from a cross between Virginia and Spanish types would eliminate genotypes with Spanish growth habit. Groups selected for high nitrogenase activity and for high shoot dry weight had longer and wider leaflets, longer cotyledonary laterals and greater main stem height than did their respective low selection groups. However, these traits chosen to characterize plant growth habit were inadequate in discriminating parental growth habits. Consequently, the data neither substantiated nor refuted the hypothesis.

Differential plant growth promotion and nitrogen fixation in two genotypes of maize by several Herbaspirillum inoculants

2014 ◽  
Vol 387 (1-2) ◽  
pp. 307-321 ◽  
Author(s):  
Gabriela Cavalcanti Alves ◽  
Sandy Sampaio Videira ◽  
Segundo Urquiaga ◽  
Veronica Massena Reis
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion

scholarly journals Examining the Effects of the Nitrogen Environment on Growth and N2-Fixation of Endophytic Herbaspirillum seropedicae in Maize Seedlings by Applying 11C Radiotracing

2021 ◽  
Vol 9 (8) ◽  
pp. 1582
Author(s):  
Spenser Waller ◽  
Stacy L. Wilder ◽  
Michael J. Schueller ◽  
Alexandra B. Housh ◽  
Stephanie Scott ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Colonization ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Growth Conditions ◽  
Significant Inhibition ◽  
Cereal Crops ◽  
Herbaspirillum Seropedicae ◽  
Promote Plant Growth ◽  
Biological Nitrogen

Herbaspirillum seropedicae, as an endophyte and prolific root colonizer of numerous cereal crops, occupies an important ecological niche in agriculture because of its ability to promote plant growth and potentially improve crop yield. More importantly, there exists the untapped potential to harness its ability, as a diazotroph, to fix atmospheric N2 as an alternative nitrogen resource to synthetic fertilizers. While mechanisms for plant growth promotion remain controversial, especially in cereal crops, one irrefutable fact is these microorganisms rely heavily on plant-borne carbon as their main energy source in support of their own growth and biological functions. Biological nitrogen fixation (BNF), a microbial function that is reliant on nitrogenase enzyme activity, is extremely sensitive to the localized nitrogen environment of the microorganism. However, whether internal root colonization can serve to shield the microorganisms and de-sensitize nitrogenase activity to changes in the soil nitrogen status remains unanswered. We used RAM10, a GFP-reporting strain of H. seropedicae, and administered radioactive 11CO2 tracer to intact 3-week-old maize leaves and followed 11C-photosynthates to sites within intact roots where actively fluorescing microbial colonies assimilated the tracer. We examined the influence of administering either 1 mM or 10 mM nitrate during plant growth on microbial demands for plant-borne 11C. Nitrogenase activity was also examined under the same growth conditions using the acetylene reduction assay. We found that plant growth under low nitrate resulted in higher nitrogenase activity as well as higher microbial demands for plant-borne carbon than plant growth under high nitrate. However, carbon availability was significantly diminished under low nitrate growth due to reduced host CO2 fixation and reduced allocation of carbon resources to the roots. This response of the host caused significant inhibition of microbial growth. In summary, internal root colonization did little to shield these endophytic microorganisms from the nitrogen environment.

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