Endophytic Nitrogen-Fixing Bacteria as Biofertilizer

Gupta, Garima; Panwar, Jitendra; Akhtar, Mohd Sayeed; Jha, Pallavi

doi:10.1007/978-94-007-5449-2_8

Cited by 62 publications

(32 citation statements)

References 175 publications

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“…For the purposes of detailed ecological assessment of hydrological changes, this approach has merit: effects of change on particular species can be evaluated. For example, Oryza longistaminata is a very important species ecologically, because it fixes atmospheric nitrogen (Gupta, Panwar, Akhtar, & Jha, 2012;Reinhold-Hurek & Hurek, 2011), a major limiting nutrient in the oligotrophic Delta (Cronberg, Gieske, Martins, Prince-Nengu, & Stenstrom, 1996;Schoelynck et al, 2017). Because of this, it exhibits elevated protein levels relative to other floodplain grasses and forms an important forage grass for livestock and wildlife (Baars & Ottens, 2001;Fynn, Murray-Hudson, Dhliwayo, & Scholte, 2015;Marchand, 1987;Scholte, 2007).…”

Section: Discussionmentioning

confidence: 99%

A suite of macrophyte species distribution models for investigating hydrology-driven spatial changes in a large flood-pulsed tropical wetland

Murray-Hudson

Wolski

Brown

et al. 2018

South African Geographical Journal

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Spatial ecological models of wetland systems are important tools for evaluating system response to changes in hydrological inputs, arising from anthropogenic manipulation or climate change. We present an approach using multiple species distribution models (SDMs) for floodplain macrophytes, based on empirical relationships with flood duration. 27 indicator species were identified for four floodplain classes in a seasonally pulsed distributary of the Okavango Delta, based on data from a field survey of 30 floodplain sites. Spatial hydrological history was constructed using a combination of Landsat and MODIS imagery, and ground-truthing. Relationships between duration and occurrence were used to construct general linear probability models (GLMs) of species along the hydroperiod gradient. The GLM parameters were then used to construct SDMs driven by a spatial hydrological model, which generates annual assessments of inundation duration in months in each 1km 2 cell across the Delta. The modelled distribution fits were mostly robust (18 GLMs had p < 0.05). Tests of model performance against a validation set of five floodplain sites showed an average of 87% correct predictions of presence. The strong performance of the models and the ability to produce map-based and quantitative output indicate good potential for use in assessment of basin development scenarios.

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Section: Discussionmentioning

confidence: 99%

A suite of macrophyte species distribution models for investigating hydrology-driven spatial changes in a large flood-pulsed tropical wetland

Murray-Hudson

Wolski

Brown

et al. 2018

South African Geographical Journal

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“…One of the most promising agro-ecological approaches that could enable the reduction of N fertilizer application, while maintaining crop productivity, is to better exploit the beneficial effects of soil microbiota and especially N 2 -fixing bacteria, that can function inside the plant and on the root surface [17–19]. These N 2 -fixing bacteria can be key players in plant N nutrition [20] because:- 1) they produce ammonia from atmospheric N 2 ; 2) endophytic N 2 -fixing bacteria are less likely to suffer competition from other microorganisms and are more likely to directly transfer the fixed N (or at least part of it) to the host plant; 3) their interaction with plants is not restricted to legumes (as is the case for root-nodulating rhizobia) and can take place extensively with maize, and 4) N 2 fixing bacteria, that can both colonize maize endophytically or on the root surface, exist in many different species of bacteria [21–22].…”

Section: Introductionmentioning

confidence: 99%

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense

et al. 2017

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Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number of metabolites exhibited a maize-genotype specific pattern of accumulation, suggesting that the highly diverse maize genetic resources could be further exploited in terms of beneficial plant-bacterial interactions for optimizing maize growth, with reduced N fertilization inputs.

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“…During the VS of the host‐plant, various metabolites are produced and mobilized for the growth of stems, branches, and leaves. Crucially, within the plant grows demand for nutrients such as nitrogen, phosphorus or iron, which are not always bioavailable (Crowley, ; Gupta, Panwar, Akhtar, & Jha, ; Hartmann, Schmid, Tuinen, & Berg, ). Therefore, the microbial groups that facilitate the intake of these nutrients could be selected by the plant and coevolve with it to supply for the physiological needs of the VS (Hartmann et al, ; Santoyo, Moreno‐Hagelsieb, Orozco‐Mosqueda Mdel, & Glick, ).…”

Section: Discussionmentioning

confidence: 99%

Comparison of specific endophytic bacterial communities in different developmental stages of Passiflora incarnata using culture‐dependent and culture‐independent analysis

et al. 2019

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Plants and endophytic microorganisms have coevolved unique relationships over many generations. Plants show a specific physiological status in each developmental stage, which may determine the occurrence and dominance of specific endophytic populations with a predetermined ecological role. This study aimed to compare and determine the structure and composition of cultivable and uncultivable bacterial endophytic communities in vegetative and reproductive stages (RS) of Passiflora incarnata. To that end, the endophytic communities were assessed by plating and Illumina‐based 16S rRNA gene amplicon sequencing. Two hundred and four cultivable bacterial strains were successfully isolated. From the plant’s RS, the isolated strains were identified mainly as belonging to the genera Sphingomonas, Curtobacterium, and Methylobacterium, whereas Bacillus was the dominant genus isolated from the vegetative stage (VS). From a total of 133,399 sequences obtained from Illumina‐based sequencing, a subset of 25,092 was classified in operational taxonomy units (OTUs). Four hundred and sixteen OTUs were obtained from the VS and 66 from the RS. In the VS, the most abundant families were Pseudoalteromonadaceae and Alicyclobacillaceae, while in the RS, Enterobacteriaceae and Bacillaceae were the most abundant families. The exclusive abundance of specific bacterial populations for each developmental stage suggests that plants may modulate bacterial endophytic community structure in response to different physiological statuses occurring at the different plant developmental stages.

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Endophytic Nitrogen-Fixing Bacteria as Biofertilizer

Cited by 62 publications

References 175 publications

A suite of macrophyte species distribution models for investigating hydrology-driven spatial changes in a large flood-pulsed tropical wetland

A suite of macrophyte species distribution models for investigating hydrology-driven spatial changes in a large flood-pulsed tropical wetland

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense

Comparison of specific endophytic bacterial communities in different developmental stages of Passiflora incarnata using culture‐dependent and culture‐independent analysis

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