Fusarium redolens

Key takeaways

Fusarium redolens belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Fusarium redolens to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Fusarium redolens from memory before moving on to harder problems.

Reference excerpt

Fusarium redolens is a species of fungus in the genus Fusarium and family Nectriaceae. This species is a soil-borne plant pathogen in temperate prairies. It causes diseases such as root, crown, and spear rot, seedling damping-off, and wilting disease. It is a known producer of the alkaloids peimisine and imperialine-3β-d-glucoside, which has implications for traditional Chinese medicine.

Taxonomy and phylogenetics Fusarium redolens was described for the first time by Hans Wilhelm Wollenweber in 1913. He originally placed it in the Fusarium section Elegans. All of the members of this group were considered synonymous with Fusarium oxysporum. However, this placing was disputed, and it has since been discovered through gene genealogies that F. redolens does not belong in the Elegans group and F. redolens is not even a sister taxon of F. oxysporum. Fusarium hostae has been found as a sister taxon to F. redolens, and they form a strongly supported clade (100% bootstrap).

Description

Mycelium The mycelium of F. redolens is composed of hyphae that have been noted to appear fibrous, powdery, or like "cotton wool." Mycelia can be white, cream, or pink. The central region appears pink and gradually lightens towards the edge where the marginal hyphae are white. F. redolens produces orange and brown pigments in the growth substrate. Colonies have been observed to grow to 75–80 mm in 10 days.

Spores F. redolens has conidia and chlamydospores. Conidia are generally smooth, cylindrical, and slightly sickle-shaped. Macroconidia have wider upper cells and hook-shaped end cells. Macroconidia have 3-5 septa and are about 45.9 by 2.58 micrometers in size. Microconidia are oval or cylinder-shaped and are about 10.68 by 3.18 micrometers in size. Chlamydospores are abundant and spherical or oval-shaped, rough-walled, and slightly pigmented.

Similarity to F. oxysporum This species' morphology is visually indistinguishable from that of Fusaruim oxysporum. Intermediates also exist between the two species. These species cause similar, at times identical, symptoms in plant hosts and can occur together in infections. Differentiating between the two species is important for the efficient management of their associated diseases through species-specific diagnostics and development of resistant germplasms in hosts. Restriction fragment length polymorphism (RFLP) analysis of the ribosomal DNA (rDNA) internal transcribed spacer (ITS) region is used to differentiate the two. They have four different nucleotides on the 28S gene.

Distribution and habitat F. redolens inhabits soil primarily in prairies. These prairies are most often in temperate areas. It is able to survive in the soil for years without a plant host. It has a worldwide range and has been isolated in Algeria, Canada, China, Germany, Greece, Italy, Kazakhstan, Lebanon, Morocco, the Netherlands, New Zealand, Pakistan, Poland, South Africa, Spain, Turkey, the United States, and the United Kingdom.

Pathogenicity Fusarium redolens is a known plant pathogen that can cause a variety of disease symptoms in the host. Recorded plant hosts are Aleppo pine, American ginseng, asparagus, barley, carnation, chickpea, flax, lentil, onion, pea, pelargonium, potato, rose, soybean, spinach, tomato, wheat, and wild rocket. Depending on the host, F. redolens causes root, crown, and/or spear rot, seedling damping-off, and wilt diseases. Symptoms of infection include brown to black necrotic lesions on roots, foliar yellowing, wilting, reduction of emergence, stunting, and rotting of seeds and seedlings. In some cases, seedlings have been found entirely deceased. In plants of the family Poaceae such as barley, heads and spikes are infected as well. It has been noted that it is a weaker pathogen on chickpea, as infections did not kill studied chickpea plants. Three host-specific strains exist and are named accordingly. F. redolens f. sp. Dianthi Gerlach, F. redolens f. sp. Spinaciae (Sherb.) Subramanian, and F. redolens f. sp. asparagi Baayen. While F. redolens causes similar symptoms in plants as Fusarium oxysporum, it is important to differentiate between these species when assessing an infection for contributions towards developing resistant germplasms in target crops.

Alkaloid production Fusarium redolens is capable of producing alkaline compounds that are similar to its host plant. Most notably, it produces peimisine and imperialine-3β-d-glucoside when inhabiting Fritillaria unibracteata var. wabuensis (FUW) as an endophyte. Both of these compounds are major alkaloids that are found in bulbus Fritillariae cirrhosae (BFC), which is an herb sourced from FUW. BFC has been used in traditional Chinese medicine for over 2000 years to treat respiratory diseases and has a $400 million USD industry surrounding it. BFC is increasingly hard to find due to long-term excessive harvesting. The ability of F. redolens to produce peimisine and imperialine-3β-d-glucoside is highly significant for the development of microbial resources to protect plant resources. However, the capacity of fungi to produce alkaloids is not as high as the host plant, so the fungi are not yet able to be used on an industrial scale.

References

Worked examples

Example 1 — a first encounter with Fusarium redolens

Start with the simplest possible case. Write down what Fusarium redolens claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Fusarium redolens before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Fusarium redolens ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Fusarium redolens

In research: Fusarium redolens appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Fusarium redolens in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Fusarium redolens is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fungal plant pathogens and diseases, Fungi described in 1913, Fungus species, so understanding it makes those chapters shorter.
In everyday life: Look for Fusarium redolens outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Fusarium redolens in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Fusarium redolens means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Fusarium redolens out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Fusarium redolens in simple terms?

Fusarium redolens is a species of fungus in the genus Fusarium and family Nectriaceae. This species is a soil-borne plant pathogen in temperate prairies.

Why does Fusarium redolens matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Fusarium redolens?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Fusarium redolens.