biology

Phoma

Phoma 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 Phoma rather than just read about it. In short: Phoma is a genus of common coelomycetous soil fungi. It contains many plant pathogenic species.

Key takeaways

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

Reference excerpt

Phoma is a genus of common coelomycetous soil fungi. It contains many plant pathogenic species.

Description Spores are colorless and unicellular. The pycnidia are black and depressed in the tissues of the host. Phoma is arbitrarily limited to those species in which the spores are less than 15 μm as the larger spored forms have been placed in the genus Macrophoma. The most important species include Phoma beta which is the cause of the heart rot and blight of beets, Phoma batata that produces a dry rot of sweet potato, and Phoma solani.

Taxonomy About 140 Phoma taxa have been defined and recognized which may be divided into two large groups: (i) plurivorous fungi, generally saprobic or weakly parasitic, mainly from temperate regions in Eurasia, but occasionally also found in other parts of the world (including areas with cool or warm climates); and (ii) specific pathogens of cultivated plants. However other estimates place the number of taxa closer to 3000, making it one of the largest fungal genera. Traditionally nine sections (Phoma, Heterospora, Macrospora, Paraphoma, Peyronellaea, Phyllostictoides, Pilosa, Plenodomus and Sclerophomella) as described by Boerema (1997) have been recognised on morphological grounds. The number of taxa in each section varied widely, from 2 (Pilosa) to 70 (Phoma). Section Phoma itself was considered incertae sedis. However phylogenetic studies suggest the genus is highly polyphyletic containing six distinct clades. Furthermore, taxa identified as Phoma have been identified across several different families within Pleosporales, but most within Didymellaceae (type genus Didymella). Furthermore, the Didymellaceae segregate into 18 clusters allowing many taxa to be distributed into separate genera. Consequently, there is little justification for retaining the sections, a number of which such as Peyronellaea are now elevated to genus rank, within Didymellaceae.

Selected species Species include:

Phoma candelariellae Z.Kocakaya & Halıcı (2016) – lichenicolous on Candelariella aurella Phoma caricae-papayae Phoma costaricensis Phoma cucurbitacearum Phoma destructiva Phoma draconis Phoma eupyrena Phoma fuliginosa – lichenicolous on Caloplaca trachyphylla Phoma glomerata Phoma herbarum Phoma insidiosa Phoma microspora Phoma narcissi Phoma nebulosa Phoma oncidii-sphacelati Phoma scabra Phoma sclerotioides Phoma strasseri Phoma tracheiphila

References

Bibliography Boerema, G. H.; de Gruyter, J.; Noordeloos, M. E.; Hamers, M. E. C. 2004. Phoma Identification Manual: Differentiation of Specific and Infra-specific Taxa in Culture. CABI. Aveskamp, M.M.; de Gruyter, J.; Woudenberg, J.H.C.; Verkley, G.J.M.; Crous, P.W. (2010). "Highlights of the Didymellaceae: A polyphasic approach to characterise Phoma and related pleosporalean genera". Studies in Mycology. 65: 1–60. doi:10.3114/sim.2010.65.01. PMC 2836210. PMID 20502538. de Gruyter, J.; Woudenberg, J.H.C.; Aveskamp, M.M.; Verkley, G.J.M.; Groenewald, J.Z.; Crous, P.W. (June 2013). "Redisposition of phoma-like anamorphs in Pleosporales". Studies in Mycology. 75 (1): 1–36. doi:10.3114/sim0004. PMC 3713885. PMID 24014897.

Illustrations

Worked examples

Example 1 — a first encounter with Phoma

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

In research: Phoma 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 Phoma 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: Phoma is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dothideomycetes genera, Fungal plant pathogens and diseases, Lichenicolous fungi, so understanding it makes those chapters shorter.
In everyday life: Look for Phoma 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 Phoma in 20 minutes

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

Frequently asked questions

What is Phoma in simple terms?

Phoma is a genus of common coelomycetous soil fungi. It contains many plant pathogenic species.

Why does Phoma 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 Phoma?

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 Phoma.