Labeled Azospirillum brasilense wild type and excretion-ammonium strains in association with barley roots

Santos, Adrian Richard Schenberger; Etto, Rafael Mazer; Furmam, Rafaela Wiegand; Freitas, Denis Leandro de; Santos, Karina F. D. N.; Souza, Emanuel Maltempi de; Pedrosa, Fábio de Oliveira; Ayub, Ricardo Antônio; Steffens, Maria; Galvão, Carolina Weigert

doi:10.1016/j.plaphy.2017.07.003

Cited by 20 publications

(15 citation statements)

References 23 publications

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“…Recently, the Azospirillum cells have been reported to infect the root hairs of barley at 12 days following inoculation as determined, using GUS-staining [22]. However, we confirmed the endophytic infection of the Azospirillum cells into plant tissues between the bulb scales to generate characteristic colonization patterns such as cell clumps with EPS production (Figure 3b).…”

Section: Discussionsupporting

confidence: 56%

“…BNF is considered to be carried out by two groups of prokaryote, composed of free-living bacteria such as cyanobacteria and Azotobacter , and plant-associated bacteria such as Azospirillum (associated with cereal) and Rhizobium (associated with legume) [20]. For the plant-associated bacteria, Azospirillum is recognized as an epiphyte localized on the root surface of the host plant [2,21,22], and considered to defend nitrogenase against O 2 by the morphological conversion into the c-form as described above. However, Rhizobium fixes nitrogen as bacteroids in the nodules formed in the roots of leguminous plants, and the partial pressure of O 2 inside the nodules is maintained at lower levels by symbiotic hemoglobin (leghemoglobin) produced by legumes [23].…”

Section: Introductionmentioning

confidence: 99%

“…To date, Azospirillum has been used to promote the growth of some crops such as wheat [3,9], barley [22], and maize [24]. Recently, a microbial inoculant containing Azospirillum has also been applied to onion, which represents a major crop in Hokkaido, Japan [25].…”

Section: Introductionmentioning

confidence: 99%

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Plant Tissue Localization and Morphological Conversion of Azospirillum brasilense upon Initial Interaction with Allium cepa L.

et al. 2019

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The genus Azospirillum is recognized as plant growth-promoting bacteria that exert beneficial effects on the host plant and is morphologically converted into cyst-like cells (i.e., c-form) in association with poly-β-hydroxybutyrate (PHB) accumulation in the cells under stress conditions. We constructed Azospirillum brasilense, labeled with reporter genes (gus/gfp, mCherry) and examined the plant tissue localization along with a morphological conversion into the c-form upon its initial interaction with onion seedlings (Allium cepa L.). The PHB granules in the A. brasilense cells were easily detected under fluorescence as “black holes”, rendering it possible to monitor the morphological conversion from vegetative to the c-form cells. The results showed that the A. brasilense cells on the surface of the roots and bulbs (underground stem) began converting at three days following inoculation and that the cell conversion was significantly advanced with time along with the cell population increase. The endophytic infection of A. brasilense into the bulb tissues was also confirmed, although these likely constituted vegetative cells. Moreover, the morphological conversion into the c-form was induced under nitrogen-restricted conditions. Analysis of the biochemical properties of the A. brasilense cells during cell conversion revealed that the acetylene reduction activity correlated positively with the PHB accumulation in the cells converting into the c-form under nitrogen-restricted conditions.

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Section: Discussionsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

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Plant Tissue Localization and Morphological Conversion of Azospirillum brasilense upon Initial Interaction with Allium cepa L.

et al. 2019

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“…Functional mutants of A. brasilense were obtained via a material transfer agreement between the corresponding author's institution and the Federal University of Paraná (UFPR, Curitiba, PR CEP 81531-980, Brazil). HM053 originated as a natural mutant of the wild-type strain of A. brasilense FP2 (Sp7 ATCC 29145 Nif + Sm r Nal r ) screened through its resistance to ethylenediamine (EDA r ) according to the original work of Machado et al [37,38]. The FP10 mutant was obtained through the original work of Pedrosa and Yates [39] by N-nitrosoguanidine mutagenesis of the FP2 wild-type strain of A. brasilense and isolated by growth on glutamate medium.…”

Section: Bacteria Growth and Root Inoculationmentioning

confidence: 99%

Functional mutants of Azospirillum brasilense elicit beneficial physiological and metabolic responses in Zea mays contributing to increased host iron assimilation

et al. 2021

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Iron (Fe), an essential element for plant growth, is abundant in soil but with low bioavailability. Thus, plants developed specialized mechanisms to sequester the element. Beneficial microbes have recently become a favored method to promote plant growth through increased uptake of essential micronutrients, like Fe, yet little is known of their mechanisms of action. Functional mutants of the epiphytic bacterium Azospirillum brasilense, a prolific grass-root colonizer, were used to examine mechanisms for promoting iron uptake in Zea mays. Mutants included HM053, FP10, and ipdC, which have varying capacities for biological nitrogen fixation and production of the plant hormone auxin. Using radioactive iron-59 tracing and inductively coupled plasma mass spectrometry, we documented significant differences in host uptake of Fe2+/3+ correlating with mutant biological function. Radioactive carbon-11, administered to plants as 11CO2, provided insights into shifts in host usage of ‘new’ carbon resources in the presence of these beneficial microbes. Of the mutants examined, HM053 exhibited the greatest influence on host Fe uptake with increased plant allocation of 11C-resources to roots where they were transformed and exuded as 11C-acidic substrates to aid in Fe-chelation, and increased C-11 partitioning into citric acid, nicotianamine and histidine to aid in the in situ translocation of Fe once assimilated.

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“…Alternatively the tagging gene can be inserted under the control of a promotor from a gene of interest to study its expression in situ [50]. Furthermore, a GusA -kanamycin reporter gene was inserted into the nifH -genes of an A. brasilense wild type and ammonium-excreting strains to facilitate an expression analysis in barley roots [51]. Quantitative data can be retrieved even from field samples, as was demonstrated by You et al [52].…”

Section: Techniques For Resolving the Diversity And Function Of The Pmentioning

confidence: 99%

Assessment of the structural and functional diversities of plant microbiota: Achievements and challenges – A review

Hartmann¹,

Fischer

Kinzel

et al. 2019

Journal of Advanced Research

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Labeled Azospirillum brasilense wild type and excretion-ammonium strains in association with barley roots

Cited by 20 publications

References 23 publications

Plant Tissue Localization and Morphological Conversion of Azospirillum brasilense upon Initial Interaction with Allium cepa L.

Plant Tissue Localization and Morphological Conversion of Azospirillum brasilense upon Initial Interaction with Allium cepa L.

Functional mutants of Azospirillum brasilense elicit beneficial physiological and metabolic responses in Zea mays contributing to increased host iron assimilation

Assessment of the structural and functional diversities of plant microbiota: Achievements and challenges – A review

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