Culture-independent molecular approaches reveal a mostly unknown high diversity of active nitrogen-fixing bacteria associated with Pennisetum purpureum—a bioenergy crop

Videira, Sandy Sampaio; Silva, Michele de Cássia Pereira e; Galisa, Péricles de Souza; Dias, Armando Cavalcante Franco; Nissinen, Riitta; Divan, Vera Lúcia Baldani; Elsas, Jan Dirk van; Baldani, José Ivo; Salles, Joana Falcão

doi:10.1007/s11104-013-1828-4

Cited by 35 publications

(20 citation statements)

References 81 publications

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“…In addition, the lower biodiversity of the active endophytic community compared with that of the total endophytic community suggests that bacterial activity is not directly related to bacterial abundance and that plant nutritional status plays an important role in determining which bacterial groups will be able to grow and be active under particular nutritional conditions. As observed earlier in the endophytic communities associated with rice (Knauth et al 2005) and elephant grass (Videira et al 2013), metabolically active endophytes may comprise a portion of the total endophytic community at a specific time, a condition which may also be true for maize.…”

Section: Discussionmentioning

confidence: 61%

Composition and activity of endophytic bacterial communities in field-grown maize plants inoculated with Azospirillum brasilense

et al. 2015

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The application of agricultural practices in which non-leguminous plants are inoculated with growth-promoting diazotrophic bacteria is gaining importance worldwide. Nevertheless, an efficient strategy for using this inoculation technology is still lacking, and a better comprehension of the environmental factors that influence a plant's ability to support its associative bacterial community is indispensable to achieving standardized inoculation responses. To address the effects of nitrogen (N)-fertilization on the diversity of both the total and metabolically active endophytic bacterial communities of field-grown maize plants, we extracted total DNA and RNA from maize plants inoculated with Azospirillum brasilense strain Ab-V5 that were growing in Oxisol and treated with regular and low levels of N-fertilizers (RN and LN, respectively). Four clonal libraries were constructed and sequenced and the dominant populations analyzed. Partial description of the bacterial diversity indicated that plants receiving RN-and LN-treatments can maintain bacterial communities with similar diversity indexes for the total endophytic bacterial community, although the communities of Novosphingobium and Methylobacterium were unevenly distributed. Fertilization management had a stronger effect on the dominant populations of the metabolically active bacterial community, and 16S rRNA gene libraries from RN plants suggested a lower diversity of such populations in comparison with libraries from LN plants. The agronomic parameters obtained at the end of the crop season indicated that the inoculation treatment was efficient in promoting plant growth. However, the combination of regular treatments with Nfertilizers and plant inoculation did not have an additive effect and actually tended to decrease crop productivity.

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Section: Discussionmentioning

confidence: 61%

Composition and activity of endophytic bacterial communities in field-grown maize plants inoculated with Azospirillum brasilense

et al. 2015

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“…Several nitrogen-fixing species, especially of Azospirillum, Herbaspirillum, Gluconacetobacter and Burkholderia genera can colonize the surface or the inner roots of sorghum (Coelho et al, 2009;Luna et al, 2010;Yoon et al, 2016), maize (Roncato-Maccari et al, 2003;Roesch et al, 2006;Montañez et al, 2009) and elephant grass (Videira et al, 2014) among other tropical grasses. But it remains unclear to what extent the plants benefit from N fixed by endophytic diazotrophs or from the production of indole-3-acetic acid (IAA) or other growth-promoting substances that are proven to cause morphological changes in roots (such as increased lateral roots and root hairs); thus, increasing nutrient absorption (Beneduzi et al, 2013;Videira et al, 2014;Alves et al, 2015). The current knowledge on the subject indicates that species such as sugarcane can fix high proportions of N in some places, particularly in Brazil Baptista et al, 2014), and have no fixation in other countries, like Australia (Biggs et al, 2002) and South Africa (Hoefsloot et al, 2005).…”

Section: Figmentioning

confidence: 99%

Nitrogen fixation of Poaceae and Leguminoseae in a green manure experiment in the Brazilian semiarid region

Neto¹,

Freitas²,

Giongo³

et al. 2017

Aust J Crop Sci

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Mixtures of green manure species, including Leguminosae and Poaceae, planted prior to commercial crops may incorporate more biomass than Leguminosae alone and fix more nitrogen than Poaceae alone. Biomass and nitrogen incorporation of three plant treatmens were compared under irrigation condition. In two mixture treatments, the same seven green manure species were planted together but with different seeding proportions. Treatment (1) (low-legume) had 50% the recommended seeding rate of the legume species (jack beans, cowpea and sunn hemp) and 150% the recommended seeding rate of the non-legume species (maize, pearl millet, sorghum and sun flower). The other treatment (2) (high-legume) had opposite proportions. In the third treatment, no green manure plants were sown and weed plants were allowed to grow. The results showed that biomass (9.1 and 8.2 Mg ha -1 ) and nitrogen accumulation (160 and 161 kg ha -1 ) did not differ between the low-legume and high-legume treatments, respectively, which were 2.5 times higher than those of the weed treatment (3.3 Mg ha -1 and 58.1 kg ha -1 ). Despite the higher non-legume biomass proportion and lower nitrogen concentration, the low-legume treatment symbiotically fixed as much N (52 kg ha -1 ) as the high-legume treatment because sorghum derived more N from the atmosphere (79 %) and maize in the same range as the legume species (37 to 54%). Therefore, sorghum and maize can have high N endophytic fixation and green manure prior to commercial crops can be produced both with legume and Poaceae species mixed together, providing a high input of N and biomass in a short period.

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“…These bacteria may be rhizospheric, epiphytic, endophytic or a combination of all of these (Turner et al, 2013). Regardless of their location, molecular genetic studies of the culturable and increasingly the non-culturable, diversity of diazotrophs associated with the aforementioned non-legumes has shown that it is enormous (Ueda et al, 1995;Engelhard et al, 2000;Burbano et al, 2011;Thaweenut et al, 2011;Fischer et al, 2012;Taul e et al, 2012;Videira et al, 2012Videira et al, , 2013Sessitsch et al, 2012;De los Santos et al, 2016). Of particular interest is the endophytic population of diazotrophs, since it was suggested that their oxygenrestricted niche within the tissues of host plants allows them to more efficiently fix N 2 , but also to exchange the fixed N-containing products (ammonium) for carboncontaining compounds (e.g.…”

Section: Introductionmentioning

confidence: 99%

The oil‐contaminated soil diazotroph Azoarcus oleariusDQS‐4^T is genetically and phenotypically similar to the model grass endophyte Azoarcus sp. BH72

Faoro

Menegazzo

Battistoni

et al. 2017

Environ Microbiol Rep

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The genome of Azoarcus olearius DQS-4 , a N -fixing Betaproteobacterium isolated from oil-contaminated soil in Taiwan, was sequenced and compared with other Azoarcus strains. The genome sequence showed high synteny with Azoarcus sp. BH72, a model endophytic diazotroph, but low synteny with five non-plant-associated strains (Azoarcus CIB, Azoarcus EBN1, Azoarcus KH32C, A. toluclasticus MF63 and Azoarcus PA01). Average Nucleotide Identity (ANI) revealed that DQS-4 shares 98.98% identity with Azoarcus BH72, which should now be included in the species A. olearius. The genome of DQS-4 contained several genes related to plant colonization and plant growth promotion, such as nitrogen fixation, plant adhesion and root surface colonization. In accordance with the presence of these genes, DQS-4 colonized rice (Oryza sativa) and Setaria viridis, where it was observed within the intercellular spaces and aerenchyma mainly of the roots. Although they promote the growth of grasses, the mechanism(s) of plant growth promotion by A. olearius strains is unknown, as the genomes of DQS-4 and BH72 do not contain genes for indole acetic acid (IAA) synthesis nor phosphate solubilization. In spite of its original source, both the genome and behaviour of DQS-4 suggest that it has the capacity to be an endophytic, nitrogen-fixing plant growth-promoting bacterium.

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Culture-independent molecular approaches reveal a mostly unknown high diversity of active nitrogen-fixing bacteria associated with Pennisetum purpureum—a bioenergy crop

Cited by 35 publications

References 81 publications

Composition and activity of endophytic bacterial communities in field-grown maize plants inoculated with Azospirillum brasilense

Composition and activity of endophytic bacterial communities in field-grown maize plants inoculated with Azospirillum brasilense

Nitrogen fixation of Poaceae and Leguminoseae in a green manure experiment in the Brazilian semiarid region

The oil‐contaminated soil diazotroph Azoarcus oleariusDQS‐4^T is genetically and phenotypically similar to the model grass endophyte Azoarcus sp. BH72

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Culture-independent molecular approaches reveal a mostly unknown high diversity of active nitrogen-fixing bacteria associated with Pennisetum purpureum—a bioenergy crop

Cited by 35 publications

References 81 publications

Composition and activity of endophytic bacterial communities in field-grown maize plants inoculated with Azospirillum brasilense

Composition and activity of endophytic bacterial communities in field-grown maize plants inoculated with Azospirillum brasilense

Nitrogen fixation of Poaceae and Leguminoseae in a green manure experiment in the Brazilian semiarid region

The oil‐contaminated soil diazotroph Azoarcus oleariusDQS‐4T is genetically and phenotypically similar to the model grass endophyte Azoarcus sp. BH72

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The oil‐contaminated soil diazotroph Azoarcus oleariusDQS‐4^T is genetically and phenotypically similar to the model grass endophyte Azoarcus sp. BH72