Article

Genome Survey and Characterization of Endophytic Bacteria Exhibiting a Beneficial Effect on Growth and Development of Poplar Trees

Brookhaven National Laboratory, Biology Department, Upton, NY 11973-5000, USA.
Applied and Environmental Microbiology (Impact Factor: 3.67). 02/2009; 75(3):748-57. DOI: 10.1128/AEM.02239-08
Source: PubMed

ABSTRACT

The association of endophytic bacteria with their plant hosts has a beneficial effect for many different plant species. Our
goal is to identify endophytic bacteria that improve the biomass production and the carbon sequestration potential of poplar
trees (Populus spp.) when grown in marginal soil and to gain an insight in the mechanisms underlying plant growth promotion. Members of
the Gammaproteobacteria dominated a collection of 78 bacterial endophytes isolated from poplar and willow trees. As representatives for the dominant
genera of endophytic gammaproteobacteria, we selected Enterobacter sp. strain 638, Stenotrophomonas maltophilia R551-3, Pseudomonas putida W619, and Serratia proteamaculans 568 for genome sequencing and analysis of their plant growth-promoting effects, including root development. Derivatives of
these endophytes, labeled with gfp, were also used to study the colonization of their poplar hosts. In greenhouse studies, poplar cuttings (Populus deltoides × Populus nigra DN-34) inoculated with Enterobacter sp. strain 638 repeatedly showed the highest increase in biomass production compared to cuttings of noninoculated control
plants. Sequence data combined with the analysis of their metabolic properties resulted in the identification of many putative
mechanisms, including carbon source utilization, that help these endophytes to thrive within a plant environment and to potentially
affect the growth and development of their plant hosts. Understanding the interactions between endophytic bacteria and their
host plants should ultimately result in the design of strategies for improved poplar biomass production on marginal soils
as a feedstock for biofuels.

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    • "KJ006 (Kwak et al., 2012), Enterobacter cloacae ENHKU01 (Liu et al., 2012), Enterobacter sp. 638 (Taghavi et al., 2009), G. diazotrophicus PaI5 (Bertalan et al., 2009), Klebsiella pneumoniae 342 (Fouts et al., 2008), Pseudomonas putida W619 (Taghavi et al., 2009), Pseudomonas stuzeri A1501 (Yan et al., 2008), Serratia proteamaculans 568 (Taghavi et al., 2009) and Stenotrophomonas maltophilia R551-3 (Taghavi et al., 2009) (Table 1). "

    Full-text · Dataset · Dec 2015
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    • "KJ006 (Kwak et al., 2012), Enterobacter cloacae ENHKU01 (Liu et al., 2012), Enterobacter sp. 638 (Taghavi et al., 2009), G. diazotrophicus PaI5 (Bertalan et al., 2009), Klebsiella pneumoniae 342 (Fouts et al., 2008), Pseudomonas putida W619 (Taghavi et al., 2009), Pseudomonas stuzeri A1501 (Yan et al., 2008), Serratia proteamaculans 568 (Taghavi et al., 2009) and Stenotrophomonas maltophilia R551-3 (Taghavi et al., 2009) (Table 1). "
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    ABSTRACT: Bacterial endophytes ubiquitously colonize the internal tissues of plants, being found in nearly every plant worldwide. Some endophytes are able to promote the growth of plants. For those strains the mechanisms of plant growth-promotion known to be employed by bacterial endophytes are similar to the mechanisms used by rhizospheric bacteria, e.g., the acquisition of resources needed for plant growth and modulation of plant growth and development. Similar to rhizospheric plant growth-promoting bacteria, endophytic plant growth-promoting bacteria can act to facilitate plant growth in agriculture, horticulture and silviculture as well as in strategies for environmental cleanup (i.e., phytoremediation). Genome comparisons between bacterial endophytes and the genomes of rhizospheric plant growth-promoting bacteria are starting to unveil potential genetic factors involved in an endophytic lifestyle, which should facilitate a better understanding of the functioning of bacterial endophytes.
    Full-text · Article · Nov 2015 · Microbiological Research
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    • "For instance, endophytes can enhance the nutrient assimilation through solubilization of mineral phosphate, production of siderophores or ammonia release (Loaces, Ferrando and Scavino 2011; Natul, Sharma and Barooah 2013). Additionally, they have been shown to possess growth-promoting traits related to growth regulatory mechanisms such as ethylene-1-aminocyclopropane-1- carboxylic acid (ACC) deaminase activity and synthesis of indole-3-acetic acid (IAA) or other auxins (Taghavi et al. 2009). Moreover, endophytic bacteria and their secondary metabolites can directly or indirectly contrast and reduce incidence of infectious plant diseases by means of antibiosis, competition for ecologic niches or nutrients, and stimulation of plant defense mechanisms (Cabanás at al. 2014; Melnick et al. 2011). "
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    ABSTRACT: This study represents the first investigation on ecology of endophytic bacteria isolated from 3 and 15 year-old vine stems of Vitis vinifera cv. Corvina. The analysis was performed by means of culture-dependent techniques. The obtained results showed that new grapevine endophytic genera are being discovered. Moreover, Bacilli and Actinobacteria are frequently isolated from 3 year-old plants, whereas Alpha- and Gamma- Proteobacteria classes are more prevalent in the 15 year-old plants. Shannon–Wiener (H) index and analysis of rarefaction curves revealed greater genus richness in young grapevine plants. Furthermore, results evidenced an increase of genotypic group number within specific genera (e.g., Rhizobium and Pantoea).
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