Sex Hormones in Fungi (With Simple Diagram)

In this article we will discuss about sex hormones in fungi :- Sirenin, Antheridiol, Oogoniol, Trisporic acid and Yeast α factor

Sex Hormones in Fungi

Sex Hormones in fungi is a diffusible substance playing specific role in the sexual reproduction.
De berry (1881) very first time reported sex hormones in Achlya ambisexualis and A.bisexualis.
Kaufmann (1972) stated that inorganic salts enhance sex hormones synthesis.
Machlis (1972) categorized sex hormones in fungi into 3 groups:
- Erogens (Control initiation and differentiation of sexual structure).
- Erotropins (Induce growth of sexual structure)
- Erotactins (Attract motile gametes)
There are five important sex hormones in fungi :- Sirenin, Antheridiol, Oogoniol, Trisporic acid and Yeast α factor

1. Sirenin

Sirenin was the first fungal sex hormone discovered.
It was discovered in Allomyces macrogynous and A. arbusculus (chytridiomycete) by Machilis (1958).
It is produced by female gametes to attracts the male gametes.
Sirenin is a bicyclic sesquiterpene diol and found as D and L form.
L is bioactive form which attract male gametes
Molecular formula is C15 H24 O2.
Molecular weight is 236 KD

2. Antheridiol

Raper (1939-1959), on the basis of his classical studies on sex hormones in Achlya, demonstrated the presence of multi hormonal regulatory system in A. ambisexualis and A. bisexualis.
In water mold Achlya (Oomcetes), Female cells produce antheridiol hormone that switches the male cells from vegetative growth to the production of many short antheridial branches.
It is a crystalline compound and steroid hormone.
It was first isolated by Mc Morris and Barksdali (1967), structure was given by Arsenault et al., (1969).
Molecular formula is C29H4205
Molecular weight is 470KD

3. Oogoniol

The hormone is synthesized by male hyphae of Achlya ambisexualis only in the presence of antheridiol.
The hormone stimulates the development of oogonium on female hyphae.
Barksdali et al. (1974) reported that oogoniol is synthesised by some hermaphrodite strains without the stimulus of antheridiol.
Two crystalline compounds, possessing Oogoniol activity have been isolated from culture filtrates of Achlya heterosexualis and named oogoniol-1 and oogoniol-2
It is a crystalline compound and steroid hormone.
Molecular formula is C29H48O5
Molecular weight is 500KD

4. Trisporic acid

Hans Burgeff (1924) observed communication between (+) and (-) strains of M. mucedo through a membrane. He concluded that low molecular weight substances diffused through the substrate.
Banbury (1954) & Plempel and Braunitzer (1958) demonstrated accumulation of substances in liquid cultures that induced zygophore formation.
Trisporic acid is a progametangia (zygophore) inducing substance.
β carotenoid is a precursor of this hormone.
Unsaturated and oxygenated form of trimethyl cyclo-hexane.
Three types: Trisporic Acid A, B, and C.
- Trisporic Acid C: Most active (80%).
- Trisporic Acid B: 15% activity.
- Trisporic Acid A: Least active (1-2%).
Molecular formula is C18H26O4
Molecular weight is 306 KD.
Collaborative Biosynthesis of Trisporic Acid
- Beta-carotene production: By both (+) and (-) strains.
- Metabolism to 4-dihydrotrisporol: By both (+) and (-) strains.
- Metabolism to 4-dihydrotrisporic acid (by + strain) and trisporol (by – strain).
- Conversion to trisporic acid: After diffusion between strains.

5. Yeast α factor

Jules Levi (1950) first discovered the involvement of Yeast α factor hormone in sexual reproduction of Saccharomyces cerevisiae.
In this fungus, the haploid cells are of two mating types ‘a’ and ‘α’ conjugate to form diploid cells.
He observed ‘a’ cells, due to influence of the chemical substance produced by ‘α’ cells, stop their growth and reproduction by budding.
Instead, these ‘a’ cells swell in size and form giant cells of various shapes. These giant cells are 30 or more times heavy in dry weight in comparison to normal haploid cells.
The yeast α factor are produced by “α” haploid cells, these α factor acts only on ‘a’ cells and has no effect on ‘α’ cells.
The α factor is reported to inhibit DNA replication in the ‘a’ cells
It Induces “a” cells to recognize and fuse with alpha cells.
It is Peptide-copper ion complex.
Molecular formula is C82H114N20O17S
Molecular weight is 1400 KD