scholarly journals Nitrogen Fixation Genes in an EndosymbioticBurkholderia Strain

2001 ◽  
Vol 67 (2) ◽  
pp. 725-732 ◽  
Author(s):  
Daniela Minerdi ◽  
Renato Fani ◽  
Romina Gallo ◽  
Alessandra Boarino ◽  
Paola Bonfante
Keyword(s):  
Genomic Library ◽  
Sequence Similarity ◽  
Bacterial Genome ◽  
Fungal Spores ◽  
Mycorrhizal Fungus ◽  
Prokaryotic Genome ◽  
Arbuscular Mycorrhizal ◽  
Open Reading Frames ◽  
Genome Screening ◽  
High Degree

ABSTRACT In this paper we report the identification and characterization of a DNA region containing putative nif genes and belonging to a Burkholderia endosymbiont of the arbuscular mycorrhizal fungus Gigaspora margarita. A genomic library of total DNA extracted from the fungal spores was also representative of the bacterial genome and was used to investigate the prokaryotic genome. Screening of the library with Azospirillum brasilense nifHDKgenes as the prokaryotic probes led to the identification of a 6,413-bp region. Analysis revealed three open reading frames encoding putative proteins with a very high degree of sequence similarity with the two subunits (NifD and NifK) of the component I and with component II (NifH) of nitrogenase from different diazotrophs. The three genes were arranged in an operon similar to that shown by most archaeal and bacterial diazotrophs. PCR experiments with primers designed on theBurkholderia nifHDK genes and Southern blot analysis demonstrate that they actually belong to the genome of the G. margarita endosymbiont. They offer, therefore, the first sequence for the nif operon described for Burkholderia. Reverse transcriptase PCR experiments with primers designed on theBurkholderia nifH and nifD genes and performed on total RNA extracted from spores demonstrate that the gene expression was limited to the germination phase. A phylogenetic analysis performed on the available nifK sequences placed the endosymbioticBurkholderia close to A. brasilense.

scholarly journals Sequence of the Genome of the Temperate, Serotype-Converting,Pseudomonas aeruginosa Bacteriophage D3

2000 ◽  
Vol 182 (21) ◽  
pp. 6066-6074 ◽  
Author(s):  
Andrew M. Kropinski
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Sequence Similarity ◽  
Complete Sequence ◽  
Open Reading Frames ◽  
Gene Encoding ◽  
Virus Family ◽  
Double Stranded Dna ◽  
High Degree ◽  
Phage Proteins ◽  
Reading Frames

ABSTRACT Temperate bacteriophage D3, a member of the virus familySiphoviridae, is responsible for serotype conversion in its host, Pseudomonas aeruginosa. The complete sequence of the double-stranded DNA genome has been determined. The 56,426 bp contains 90 putative open reading frames (ORFs) and four genes specifying tRNAs. The latter are specific for methionine (AUG), glycine (GGA), asparagine (AAC), and threonine (ACA). The tRNAs may function in the translation of certain highly expressed proteins from this relatively AT-rich genome. D3 proteins which exhibited a high degree of sequence similarity to previously characterized phage proteins included the portal, major head, tail, and tail tape measure proteins, endolysin, integrase, helicase, and NinG. The layout of genes was reminiscent of lambdoid phages, with the exception of the placement of the endolysin gene, which parenthetically also lacked a cognate holin. The greatest sequence similarity was found in the morphogenesis genes to coliphages HK022 and HK97. Among the ORFs was discovered the gene encoding the fucosamine O-acetylase, which is in part responsible for the serotype conversion events.

scholarly journals Mycorrhizal dependency and growth response of Gliricidia sepium (Jacq.) Kunth ex Walp. under saline condition

2017 ◽  
Vol 4 (4) ◽  
pp. 154-160 ◽  
Author(s):  
Bhoopander Giri
Keyword(s):  
Salinity Stress ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Gliricidia Sepium ◽  
Mycorrhizal Symbiosis ◽  
Saline Condition ◽  
Mycorrhizal Dependency ◽  
Mycorrhizal Association ◽  
Significant Difference ◽  
High Degree

In pursuit of salinity-mycorrhiza interaction, a pot experiment was conducted to determine the dependence of Gliricidia sepium on arbuscular mycorrhizal association under salinity stress, which was imposed using different concentrations of sodium chloride solutions. The present study revealed that arbuscular mycorrhizal fungus; Rhizophagus fasciculatus significantly increased growth and biomass of G. sepium plants under saline condition. G. sepium showed a high degree of dependence on mycorrhizal symbiosis under saline as compared to non-saline condition. Under non-saline condition (SS0), G. sepium plants exhibited 23.9% dependence on R. fasciculatus, which increased with increase in the levels of salinity. At SS3 level, G. sepium plants showed 46.6% mycorrhizal dependency followed by SS2 and SS1 levels of salinity. However, there was no significant difference between mycorrhizal dependency of G. sepium at SS1 and SS2 levels of salinity. Improved growth of G. sepium under salinity stress revealed R. fasciculatus a promising inoculant for the reclamation of degraded saline soils.

scholarly journals Phosphorus Availability Influences Elemental Uptake in the Mycorrhizal Fungus Glomus intraradices, as Revealed by Particle-Induced X-Ray Emission Analysis

2008 ◽  
Vol 74 (13) ◽  
pp. 4144-4148 ◽  
Author(s):  
Pål Axel Olsson ◽  
Edith C. Hammer ◽  
Håkan Wallander ◽  
Jan Pallon
Keyword(s):  
Glomus Intraradices ◽  
Fungal Spores ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
Spore Wall ◽  
P Availability ◽  
Emission Analysis ◽  
Pixe Analysis ◽  
X Ray

ABSTRACT We investigated element accumulation in the arbuscular mycorrhizal fungus Glomus intraradices. Fungal spores and mycelia growing in monoxenic cultures were analyzed. The elemental composition was quantified using particle-induced X-ray emission (PIXE) in combination with scanning transmission ion microscopy. In the spores, Ca and Fe were associated mainly with the spore wall, while P and K showed patchy distributions and their concentrations were correlated. Excess of P in the hyphal growth medium increased the P and Si concentrations in spores and increased the K/Ca ratio in spores. Increased P availability decreased the concentration of Zn and Mn in spores. We concluded that the availability of P influences the uptake and accumulation of several elements in spores. It is demonstrated that PIXE analysis is a powerful tool for quantitative analysis of elemental accumulation in fungal mycelia.

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