Substrate utilization by endophytic bacteria <i>Paenibacillus polymyxa</i> P2b-2R that may facilitate bacterial entrance and survival inside diverse plant hosts

Yang, Henry; Puri, Akshit; Padda, Kiran Preet; Chanway, C. P.

doi:10.1139/facets-2016-0031

Cited by 23 publications

(7 citation statements)

References 34 publications

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“…we were able to isolate a much higher number of endophytic bacteria that showed positive N-fixing ability in ARA. This is consistent with the results of Yang et al (2016Yang et al ( , 2017 (Tables 1 and 2). These…”

Section: Discussionsupporting

confidence: 92%

Isolation and identification of endophytic diazotrophs from lodgepole pine trees growing at unreclaimed gravel mining pits in central interior British Columbia, Canada

2018

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Unreclaimed gravel mining pits located in the central interior of British Columbia have very limited soil N-levels due to gravelly-textured soils with weak profile development, no organic forest floor, and low atmospheric nitrogen (N) inputs through precipitation. However, lodgepole pine (Pinus contorta var. latifolia) trees can be found growing well at these pits with tissue Ncontent and growth rate unaffected by extremely low soil N-levels, indicating that pine trees are able to meet their N-requirements from an unknown source. We hypothesized that biological Nfixation by bacteria living in the tree tissues (known as endophytic diazotrophs) could be a potential N source for these trees. To test this hypothesis, we isolated 77 potential endophytic diazotrophs from needle, stem and root tissues of pine trees on N-free culture media. Of these, 32 bacteria showed positive N-fixing ability when tested for nitrogenase enzyme activity using the acetylene reduction assay. These endophytic N-fixing bacteria were identified as mainly belonging to the genera Pseudomonas, Bacillus, Paenibacillus, and Rhizobium, which are well-known for their plant-beneficial traits including N-fixation. Therefore, it can be concluded that pine trees growing at these severely N-limited gravel pits naturally harbour endophytic diazotrophs, which could be involved in sustaining their vigorous growth, possibly through biological nitrogen fixation.

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Section: Discussionsupporting

confidence: 92%

Isolation and identification of endophytic diazotrophs from lodgepole pine trees growing at unreclaimed gravel mining pits in central interior British Columbia, Canada

2018

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“…After the incubation period, the agar was flooded with Congo red solution (0.5% w/v) for 30 min, drained, and then rinsed with 1 mol/L NaCl (Yang et al 2017). The clear zone around the bacterial colony indicated cellulose degradation.…”

Section: Qualitative Analysis Of Plant Growth Promoting Traitsmentioning

confidence: 99%

Effect of GFP-tagging on nitrogen fixation and plant growth promotion of an endophytic diazotrophic strain ofPaenibacillus polymyxa

Padda¹,

Puri²,

Zeng³

et al. 2017

Botany

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Green fluorescent protein (GFP), a renowned marker protein, is typically believed to be inert in affecting the physiology of host bacteria. We analyzed the effects of GFP-tagging on the ability of an endophytic diazotroph, Paenibacillus polymyxa P2b-2R, to fix nitrogen and promote overall growth of corn plants. The growth response and the amount of nitrogen fixed by P2b-2Rgfp-inoculated plants were compared with uninoculated controls and P2b-2R-inoculated plants at three harvests. P2b-2Rgfp inoculation significantly increased the biomass of corn plants as compared to non-inoculated controls and P2b-2R-treated plants. In vitro tests revealed that strains P2b-2R and P2b-2Rgfp possess various plant-growth-promoting characteristics, namely phosphate solubilization, production of siderophores, IAA, ammonia, and enzymes like cellulase, protease, and catalase. P2b-2Rgfp-inoculated plants fixed 18% atmospheric nitrogen, significantly higher than P2b-2R-inoculated plants (15%). This difference led us to compare the expression of structural nif genes (nifH, nifD, nifK) of strains P2b-2R and P2b-2Rgfp. It was observed that expression levels of structural nif genes of strain P2b-2Rgfp were 1.5-fold higher than those of strain P2b-2R. These results indicate that GFP-tagging positively affects the efficacy of strain P2b-2R to promote plant growth and fix nitrogen, perhaps by increasing the expression levels of structural nif genes.

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“…In this study results showed most of the isolates identified to be Bacillus species, for example, isolate GSN1XGroot from the roots of Xylocarpus granatum collected from Gazi bay expressed presence of amylases, caseinases, cellulases and chitinases suggesting a possible ecological role of these enzymes in the symbiotic relationship of the isolates and the host plants [23].…”

Section: Discussionmentioning

confidence: 57%

Enzymatic Activity of Endophytic Bacterial Isolates from Selected Mangrove Plants in Kenya

Ntabo¹,

Nyamache²,

Lwande³

et al. 2018

TOMICROJ

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Introduction:Microorganisms are a preferred source of enzyme production due to their high production capability and low cost of production. Bacterial endophytes occupy unexplored sites hence they represent a new source of enzymes with diverse applications. Mangrove plants in Kenya have traditionally been used as medicinal plants due to their bioactive metabolites. However the enzymatic activity of mangrove plants associated endophytes has not been studied.Aims & Objectives:The study is aimed at bioprospecting for enzymes with potential biotechnological applications from mangrove ecosystems.Methods & Materials:Forty-two bacterial isolates were cultured and isolated from the leaves and roots of six mangrove plants sampled from Mida Creek and Gazi Bay in the coastal region of Kenya. The isolates were screened for pectinases, chitinases, cellulases, proteases, and amylases. The isolates were identified based on morphology and 16S rRNA gene sequences analysis.Results:The study showed bacterial isolates had enzymatic activity as follows; pectinases activity (69% of the isolates), Proteases (95% of the isolates), amylases activity (88% of the isolates), cellulases and chitinases (92% of the isolates each). Bacterial endophytes from leaves showed a higher enzymatic index of cellulases suggesting a potential role in degrading cellulose in the leaves of plants. The enzymes amylases and proteases were mostly exhibited by endophytes in roots suggesting a potential role in metabolizing sugar and amino acids in the roots. Isolates from the mangrove plantSonneratia albashowed highest enzymatic indices. The study also observed that isolates from mangrove plants sampled from Gazi bay had high means of enzymatic indices. Molecular identification showed the isolates were closely related toBacillus, Streptomyces, Myroides, andStaphylococcusspecies. Their respective enzymatic activities have been provided in this study.Conclusion:The study showed that Kenyan Mangrove plant-associated bacterial endophytes provide a good reservoir of enzymes with potential industrial applications.

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Substrate utilization by endophytic bacteria Paenibacillus polymyxa P2b-2R that may facilitate bacterial entrance and survival inside diverse plant hosts

Cited by 23 publications

References 34 publications

Isolation and identification of endophytic diazotrophs from lodgepole pine trees growing at unreclaimed gravel mining pits in central interior British Columbia, Canada

Isolation and identification of endophytic diazotrophs from lodgepole pine trees growing at unreclaimed gravel mining pits in central interior British Columbia, Canada

Effect of GFP-tagging on nitrogen fixation and plant growth promotion of an endophytic diazotrophic strain ofPaenibacillus polymyxa

Enzymatic Activity of Endophytic Bacterial Isolates from Selected Mangrove Plants in Kenya

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