What is the Difference Between Holobasidium and Phragmobasidium

The main difference between holobasidium and phragmobasidium is that holobasidium is a non-septate basidium, whereas phragmobasidium is a septate basidium. 

Holobasidium and phragmobasidium are two types of basidia that occur in Basidiomycota. They form sexual spores. 

Key Areas Covered

1. What is Basidium
– Definition, Anatomy, Importance
2. What is Holobasidium
– Definition, Anatomy, Importance
3. What is Phragmobasidium
– Definition, Anatomy, Importance
4. Similarities Between Holobasidium and Phragmobasidiuma
– Outline of Common Features
5. Difference Between Holobasidium and Phragmobasidium
– Comparison of Key Differences
6. FAQ – Holobasidium and Phragmobasidium
– Answers to frequently asked questions

Key Terms

Holobasidium, Phragmobasidium

What is Basidium

Basidium is a type of sporangium that is microscopic. Therefore, the primary function of basidium is to produce spores. Usually, basidium occurs in the hymenophore of the fruiting bodies of the Basidiomycota, a division of fungi. 

Basidium also occurs in the tertiary mycelium that develops from the secondary mycelium. In general, tertiary mycelium is the highly-coiled secondary mycelium, and it is a dikaryon. However, the presence of basidium is the main characteristic feature of the division Basidiomycota. On the other hand, basidium bears four basidiospores. Occasionally, the number of basidiospores can vary from two to eight.

Figure 1: Basidium

Moreover, basidiospores occur at the tip of the narrow horn, known as sterigma. The dispersal of basidiospores occurs forcibly, discharged upon maturity. Apart from that, the shape of the basidium is like a club. The basidium is narrow at the end and broader near the outer end. In addition to that, the immature basidium is known as basidiole. There are two types of basidia according to the number of cells in the basidium. They are holo-basidia, which contain a single-celled basidium, and phragmobasidia, which are multicellular.

What is Holobasidium

Holobasidium is a non-septate basidium, which is single-celled. Also, it is club-shaped. Additionally, it contains four sterigmata. There are two types of holobasidium. They are chiastobasidium and stichobasidium. Chiastobasidium is a type of holobasidium in which microtubules are arranged perpendicular to the long axis of the basidium. In contrast in stichobasidium, microtubules arrange parallel to the long axis of the basidium.  

Furthermore, a typical basidium is club-shaped. It is wider near its outer end and narrow at the stem. The middle hemispherical dome is the widest. Inverted egg-like basidia also occur in genera like Paullicorticium, Oliveonia, and Tulasnella. Further, barrel-like basidia arise with a broad base as well. 

What is Phragmobasidium

Phragmobasidium is a septate basidium. The rust fungi in the order Puccinales contains four cells separated by the walls along their cross sections. It is shaped like a cross. Also, some jelly fungi in the order Tremellales contain walls similar to a cross.

Figure 2: Rust Fungi

Similarities Between Holobasidium and Phragmobasidium

• Holobasidium and phragmobasidium are two types of basidia.
• They occur in Basidiomycota.
• They form sexual spores.

Difference Between Holobasidium and Phragmobasidium

Definition

Holobasidium refers to a non-septate unicellular basidium characteristic of the basidiomycetes. In contrast, phragmobasidium refers to a septate unicellular basidium.

Septa

Holobasidium does not contain septa, while phragmobasidium contains septa.

Type of Septa

No septa occur in holobasidium, while septa are transverse or longitudinal in phragmobasidium.

Number Cells

Basidia are single-celled in holobasidium, while basidia have four cells in phragmobasidium.

FAQ: Holobasidium and Phragmobasidium

What are the different types of Holobasidium?

Holobasidiomycetes include gilled mushrooms, polypores, boletes, chanterelles, tooth fungi, and crust fungi. Phragmobasidia and heterobasidia are other types of basidia. 

What is the difference between sterigma and basidium? 

An apical extension of the basidium is the sterigma that bears basidiospores. Four sterigma occurs per basidium.

What are the main differences between Ascomycetes and Basidiomycetes? 

The spores of ascomycetes occur through sac-shaped cells called Ascus. In comparison, spores of the basidiomycetes occur through a club-shaped sac called basidium. 

Conclusion

In brief, holobasidium and phragmobasidium are two types of basidia that occur in Basidiomycota, forming sexual spores. Holobasidium does not contain septa. It is single-celled. In comparison, phragmobasidium contains septa that are transverse or longitudinal. Also, basidia have four cells. Therefore, the main difference between holobasidium and phragmobasidium is the presence of septa.        

References:

1. Wikimedia Foundation. (2023a, August 12). Basidium. Wikipedia. 
2. Lecture 5 basidiomycota I – KSMC aurangabad. (n.d.). 

Image Courtesy:

1. “Basidium schematic” By Debivort – Own Work (CC BY SA 3.0) via Commons Wikimedia
2. “Bruine roest op tarwe (Puccinia recondita f.sp. tritici on Triticum aestivum)” By Rasbak – Own Work (CC BY SA 3.0) via Commons Wikimedia