Frankia sp

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Higher order taxa

Bacteria; Actinobacteria; Actinobacteria (Class); Frankiales; Frankiaceae; Frankia


NCBI: [1]

Frankia sp

Description and significance

Frankia is a nitrogen-fixing bacterium that forms a symbiotic relationship with actinorhizal plants.This symbiosis is called actinorhizal and the infected plants are called actinorhizal plants. Frankia is difficult to isolate from soil. In 1959, Pommer was the first to report the first successful isolation of a Frankia strain. Pommer acquired the strain from Alnus Glutinosa root nodules and used glucose-asparagine agar [1]. In 1978, Maurice Lalonde isolated the EAN1pec strain from Frankia sp. It grows slowly on dicarboxylic acids [2]. Ammonia is the most effective nitrogent source to grow Frankia. Frankia is nonpathogenic to humans and animals [1]. "Frankia sp are filamentous "euactinomycetes" that grow by hyphal branching and tip extension and thus resemble the antibiotic-producing Streptomyces sp" [2].

Frankia sp is Gram positive and the bacterium shape is round and can also be irregularly shaped. They are unable to grow in anaerobic conditions. They form colonies and are typically slow growing with a doubling time of 20 hours to several days [1]. During growth, Frankiae produce three cell types; vegetative hyphae, sporangiospores and vesicles [2]. Frankia also has envelopes with up to 90 layers made of bacteriohopane and its derivatives. The Frankia strain has sporangia, some which are sessile, and sporangiophores, which are nonmotile [1].

Genome and genetics

a. To what major branch of the prokaryotes do they belong? (see textbook or Bergey’s). List 2-3 closely related but separate species or genera of bacteria.

b. Briefly describe any extra-chromosomal elements or genetic tools that are used to study the bacterium: viruses, plasmids, transposons that allow genetic manipulation and analysis.

c. Has the genome or genomes been sequenced? If so, include the website for the database and one or two highlights of the genome. Also indicate genome size (base pairs), %G+C (nucleotide base composition) and number of genes, and specific genes or gene regions that are unique to this organism. If it has not been sequenced, give its closest relative that has been sequenced, its website, and some general information about the related sequence.

Example: The sequence of Haemophilus influenzae was determined using whole genome shotgun sequencing (Fleischmann et al. 1995).

Nutrition and metabolism

a.Describe the growth characteristics of your bacterial species; sources of C, N, electrons; respires/ferments, uses O2, etc.

b.What kinds of culture conditions (temp, pH, media) are needed for laboratory study?

c.What kinds of waste, by-products, volatile compounds are generated?

Ecology / Pathology

Ecology: How is your microorganism important in the ecosystem where it is found? How does it impact other organisms in the environment (could be positive or negative impact)?

Pathology: How does the microbe cause disease as it interacts with the host? Describe any specific toxins or pathways that are used for invading and causing disease in the host. What treatment is used to inhibit or kill the microbe?

Current Research

Describe recent research and findings that have been done with this organism. The research can be clinical, applied or basic research. This section should be based on 2 recent papers (10 years or less) and summarized in your own words.


1. Bergey DH, Whitman WB. Bergey's Manual of Systematic Bacteriology: The Actinobacteria Volume 5. 2nd ed. s.l.: Springer-Verlag New York Inc.; 2010.

2. Home - Frankia sp. EAN1pec. Home - Frankia sp. EAN1pec. 2014 [accessed 2017 Feb 13].

For an example, see this entry: