biology

Septobasidium

Septobasidium is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Septobasidium rather than just read about it. In short: Septobasidium is a fungal genus within the family Septobasidiaceae. Approximately 175 described species are associated with this genus. 227 records are listed by Species Fungorum.

Key takeaways

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

Reference excerpt

Septobasidium is a fungal genus within the family Septobasidiaceae. Approximately 175 described species are associated with this genus. 227 records are listed by Species Fungorum. Septobasidium species are known to be entomopathogens.

Description Septobasidium spp. are characterized by their presence on the underside of branches and leaves of deciduous trees, shrubs and in a symbiotic association with scale insects (Coccoidea), such as the Latania Scale Insect, Hemiberlesia lataniae. Also the European pear scale (Epidiaspis leperii (Signoret 1869)) and Septobasidium marianii Bres. which created a mutualistic symbiosis formed by the fungus and the scale insects on fruit trees in Slovenia. Fruiting bodies form a crust (resupinate) and range in color and size, from small patches (1 mm in diameter) to 2 meters wide. Species of this genus are often distinguished based on the thickness of the fruiting body. Some species form elaborate chambers and tunnels that house scale insects with top and bottom layers while others form a very thin hyphal network. Microscopic characteristics, such as the number of basidiospores produced on a basidia, presence of pillars supporting the top layer (if applicable), number of cells in a basidia, and shape of haustoria (infectious cells) that form within the scale insects are used to distinguish species. Septobasidium is unique in that it is one of a few genera within the family Septobasidaceae that exists in symbiotic relationships with scale insects ranging from obligately parasitic to mutualistic. This type of fungus is fairly unique for having a mutualistic relationship with scale insect hosts, rather than killing them. Although it weakens the insects it parasitizes, it does not kill them and it benefits the population as a whole, helping provide protection from parasitoid wasps by forming a mycelial mat that helps conceal the insects. The fungus benefits from the relationship, as it is nourished by the waste products the insects produce.

Symbiotic association with insects Couch proposed in 1938 that the symbiotic relationship between Septobasidium and scale insects was mutualistic. He suggested that at a population level, scale insects benefit from certain species of Septobasidium that provide protection from predators, and prevent desiccation. Couch also remarked that some scale insects remain uninfected while others are infected and rendered sterile. Some Septobasidium species provide no discernable shelter and parasitize all scale insects associated with the fruiting body. This suggests that the symbiotic relationships within this genus are complex, and merit further investigation. Additionally, no clear benefit has been demonstrated for scale insects associated with the fungus compared to free-living scale insects. The scale insect itself is a parasite of the host tree or shrub, resulting in a tri-partite symbiosis between the fungus, insect, and tree. The fungus itself does not parasitize the tree tissue and the scale insects do not need the fungus to survive. During the spring months, basidia gives rise to sexual spores known as basidiospores that are capable of infecting a first instar scale insect walking across the surface of the fruiting body. The infected insect will either 1) settle with other scale insects within the same fruiting body it was infected by, 2) travel to another fruiting body and settle, or 3) move to an un-infected plant tissue and settle, forming a new colony of the fruiting body. Scale insects are mobile during the first instar after hatching, which co-occurs in the spring when basidiospores are released. Scale insects begin to feed on plant sap and settle into one location, eventually molting and shedding legs. Hyphae emerge from natural openings of infected insects and form a mycelial mat above the infected and non-infected insects. The life cycle completes itself when hyphae gives rise to new basidiospores on the surface of the mycelial mat during spring rain events, and infects the next generation of scale insects.

Illustrations

Worked examples

Example 1 — a first encounter with Septobasidium

Start with the simplest possible case. Write down what Septobasidium 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 Septobasidium 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 Septobasidium 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 Septobasidium

In research: Septobasidium 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 Septobasidium 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: Septobasidium is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fungal plant pathogens and diseases, Pucciniomycotina, Taxa named by Narcisse Théophile Patouillard, so understanding it makes those chapters shorter.
In everyday life: Look for Septobasidium 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.

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How to study Septobasidium in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Septobasidium 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 Septobasidium out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Septobasidium in simple terms?

Septobasidium is a fungal genus within the family Septobasidiaceae. Approximately 175 described species are associated with this genus. 227 records are listed by Species Fungorum.

Why does Septobasidium 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 Septobasidium?

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 Septobasidium.