Nitrogen-Fixing Bacteria in Eucalyptus globulus Plantations

Silva, Marliane de Cássia Soares da; Paula, Thiago de Almeida; Moreira, Bruno Coutinho; Carolino, Manuela; Cruz, Cristina; Bazzolli, Denise Mara Soares; Silva, Cynthia Canedo; Kasuya, Maria Catarina Megumi

doi:10.1371/journal.pone.0111313

Cited by 16 publications

(25 citation statements)

References 31 publications

(3 reference statements)

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“…2). Such diazotrophs were also detected in other studies on root-associated BNF of trees, but the diversity of active diazotrophs was much higher in these studies, indicating a non-specific association of diazotrophs with tree roots4243. In our study, however, the expression of Bradyrhizobiaceae and Burkholderiaceae related nifH was essentially only detected in peat, indicating that free-living Bradyrhizobiaceae and Burkholderiaceae contribute to BNF in peat rather than to BNF in root nodules of L. fonkii .…”

Section: Discussionsupporting

confidence: 54%

Associative nitrogen fixation in nodules of the conifer Lepidothamnus fonkii (Podocarpaceae) inhabiting ombrotrophic bogs in southern Patagonia

Borken

Horn

Geimer

et al. 2016

Sci Rep

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Biological N2 fixation (BNF) in the rhizosphere of Podocarpaceae is currently attributed to unspecific diazotrophs with negligible impact on N acquisition. Here, we report specific and high associative BNF in dead cells of root nodules of Lepidothamnus fonkii distributed in ombrotrophic peatlands of Patagonia. BNF of nodulated roots, intact plants of L. fonkii and rhizospheric peat was assessed by 15N2 and acetylene reduction. Diazotrophs were identified by electron microscopy, analysis of nitrogenase encoding genes (nifH) and transcripts, and 16S rRNA. Nitrogenase encoding nifH transcripts from root nodules point to Beijerinckiaceae (Rhizobiales), known as free-living diazotrophs. Electron microscopy and 16S rRNA analysis likewise identified active Beijerinckiaceae in outer dead cells of root nodules. NifH transcripts from the rhizopshere peat revealed diverse active diazotrophs including Beijerinckiaceae. Both methods revealed high activity of nitrogenase rates in cut roots of L. fonkii (2.5 μmol N g−1 d.w. d−1 based on 15N2 assay; 2.4 μmol C2H4 g−1 d.w. d−1 based on acetylene reduction assay). The data suggest that (i) nodules recruit diazotrophic Beijerinckiaceae from peat, (ii) dead nodule cells provide an exclusive habitat for Beijerinckiaceae, and (iii) BNF in L. fonkii is one potent pathway to overcome N deficiency in ombrotrophic peatlands of Patagonia.

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Section: Discussionsupporting

confidence: 54%

Associative nitrogen fixation in nodules of the conifer Lepidothamnus fonkii (Podocarpaceae) inhabiting ombrotrophic bogs in southern Patagonia

Borken

Horn

Geimer

et al. 2016

Sci Rep

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“…Microbial diversity can also be studied by analyzing the total DNA of the microbiota extracted directly from the plant for processing using electrophoretic techniques . Studies using these techniques have contributed to a better understanding of the microbial community structure and have led to new perspectives and advances in ecological studies (Hoshino and Matsumoto, 2007;Oliveira et al, 2013;Da Silva et al, 2014). Thus, the present study aimed at evaluating the composition and diversity of the endophytic fungal community in eucalyptus leaves at the onset of the rainy period and during the rainy and dry periods.…”

Section: Introductionmentioning

confidence: 99%

Diversity and distribution of the endophytic fungal community in eucalyptus leaves

Miguel¹,

Delvaux²,

Oliveira³

et al. 2017

Afr. J. Microbiol. Res.

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Eucalyptus species are among the most widely grown and most economically valuable trees worldwide. In Brazil, eucalyptus is of major environmental and economic importance because it generates thousands of jobs and offers an alternative to using wood from native forests. In forest ecosystems, plant shoots are considered a common habitat for various microorganisms, and plants of the family Myrtaceae are an important source of fungal biodiversity. However, very little is known about the diversity and microbial distribution in eucalyptus leaves. This study aimed at showing the diversity and distribution of endophytic fungi in the leaves of eucalyptus plants aged 18 and 72 months. The leaves were collected at the onset of the rainy period, during the rainy period, and during the dry period. Diversity was measured using DNA extraction, 18S rRNA subunit amplifi cation, denaturing gradient gel electrophoresis (DGGE), and sequencing of eluted bands. The endophytic fungal community was affected by plant location. Differences observed in the distribution of the phylogenetic groups found in the upper, middle and lower thirds of the tree canopy indicate that the endophytic community distribution in eucalyptus is dependent on leaf position. The age of the plants affected the diversity of endophytic fungi in Eucalyptus "urograndis". Phylogenetic analysis showed that the phyla Basidiomycota and Ascomycota dominate in the environments studied. The description of endophytic fungal diversity in this important forest species is an important step for assessing this genetic resource in the search for metabolites and processes tha t can contribute to improving plant development.

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“…The maintenance of harvest residues on the soil increases soil C and N pools-especially in labile fractions-thereby increasing the capacity of upper layers to provide N to plants [14][15][16]30]. The remaining difference possibly came from deeper layers of the soil profile and factors such as biological fixation by symbiotic associations which were not examined in this study [40]. Despite the large difference in the nutrient outputs between ReM + F and ReR + F treatments (more than 500 kg·ha -1 in the net balance), no differences in the N stocks between these treatments were found in the deeper layers of the soil (20-200 cm).…”

Section: Soil Contribution To Nutrients Absorbed By Treesmentioning

confidence: 86%

Effect of Timber Harvest Intensities and Fertilizer Application on Stocks of Soil C, N, P, and S

Menegale

Rocha

Harrison

et al. 2016

Forests

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Abstract:The purpose of this study was to determine the stocks of available P and S, total N, and oxidizable C at depth in an Oxisol cultivated with Eucalyptus in Brazil following different timber harvest intensities and fertilizer application over 12 years. The harvest regimes considered were (i) conventional stem-only harvest (all forest residues were maintained on the soil); (ii) whole-tree harvest (only litter was maintained on the soil-all slash, stemwood, and bark were removed); and (iii) whole-tree harvest + litter layer removal. The site was planted in 2004 considering three timber harvest intensities, some with and some without N and P fertilization. In 2012 the experiment was reinstalled, and all the treatments were reapplied in the each plot. From 2004 to 2016, nutrient accumulation and soil N, P, and S stocks were assessed in the 0-20 cm layer. Also in 2016, soil N, P, S, and oxidizable C stocks were measured to 2 m depth. For each treatment, the net balance of N, P, and S were calculated from soil stocks and harvest outputs during two forest rotations. A reduction in all nutrient stocks was observed in the 0-20 cm layer for all treatments. For N, this reduction was 20% smaller in the stem-only harvest treatment and 40% higher when no N fertilizer was applied, when compared to other treatments. Stem-only harvest treatment was observed to reduce the loss of N, P, and S due to harvest by 300, 30, and 25 kg·ha −1 , respectively, when compared to the whole-tree harvest + litter layer removal treatment.

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Nitrogen-Fixing Bacteria in Eucalyptus globulus Plantations

Cited by 16 publications

References 31 publications

Associative nitrogen fixation in nodules of the conifer Lepidothamnus fonkii (Podocarpaceae) inhabiting ombrotrophic bogs in southern Patagonia

Associative nitrogen fixation in nodules of the conifer Lepidothamnus fonkii (Podocarpaceae) inhabiting ombrotrophic bogs in southern Patagonia

Diversity and distribution of the endophytic fungal community in eucalyptus leaves

Effect of Timber Harvest Intensities and Fertilizer Application on Stocks of Soil C, N, P, and S

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