Fungi belong to the Fungi Kingdom and the Eukaryota domain. They are heterotrophic organisms of saprotroph or absorption nutrition, cosmopolitan distribution and mostly anaerobic breathing. More than 145,000 fungal species have been described but it is estimated that there could be more than 2.2 million species yet to be discovered.
Fungi play a fundamental role in trophic chains because they are decomposing of matter par excellence. They can be unicellular or multicellular and have ecological, pharmacological, medical, food and industrial importance.
One of the distinctive characteristics of fungi is that they have the ability to reproduce both sexually and asexually. If you want to know more about the subject, read this interesting ecology article see and discover How fungi reproducewhether sexually and asexually.
How is the reproduction of fungi
In order to understand how fungi reproduce, we must first know how they are classified. If we classify fungi According to the edge To which they belong, these can be:
- Glomeromicetos.
- Removal.
- Ascomycetes
- Zigomicetos
- Basidiomycetes.
On the other hand, if we classify them according to its type of reproduction They can be:
- Perfect fungi: They are all those who can reproduce both sexually and asexually. Regardless of the edge to which they belong, this type of fungi can alternate to convenience sexual and asexual reproductive cycles. More than 90% of known fungi species are part of this classification.
- Imperfect fungi: Also called deuteromycetes are all those who regardless of their edge do not have a documented sexual reproductive process. Imperfect fungi only reproduce asexually and represent only 10% of total known fungi. Glomeromycetes are the main representatives of this group.
All fungi reproduce through spores. These can originate through sexual or asexual processes, disperse thanks to the incidence of wind, water, animals, etc. and They germinate with favorable environmental conditions; First forming hyphae and then developing mycelios. On the other hand, fungi talus can be holocardial or eucacharpic.
- Holocardial talos: They have the ability to completely become a reproductive structure, preventing the somatic and reproductive phases from coexisting at the same time and individual.
- Eucárpico talos: They have differentiated reproductive structures that allow the somatic and reproductive phases to coexist.
If you want to know more about the classification of fungi or what are the spores, do not hesitate to take a look at these other articles that we recommend.
Sexual reproduction of fungi
Sexual reproduction is exclusive of perfect fungi. These can be of any edge, although zigomicose fungi, ascomycetes and basidiomycetes have a tendency to be part of this group. In the vast majority of cases the fungi that reproduce sexually also reproduce asexually.
Although sexual reproduction is delayed and generates less offspring, fungi practices it for:
- Increase your Genetic variability.
- Face different unfavorable diseases or conditions.
In sexual reproduction two individuals of the same species unite their genetic material to create a new individual who possesses characteristics of both. There are several mechanisms through which fungi reproduce sexually, but the most important are:
- Somatogamia: Two close fungi of the same species fuse their vegetative cells or somatic hyphae to form a zygote. This can be homotallic (if the hyphae belong to the same individual) or heterotálicas (if the hyphae belong to different individuals).
- Gametangio: The male and female sex cells of two fungi of the same species connect and transfer the gametic nuclei through a fertilization tube.
- Gametangiogamia or gametangial copulation: The gametangios of two nearby fungi are in touch to create a zygote containing the genetic material of both.
- Processes involving mobile and/or immobile gametes: Reproduction is carried out by spores or sperm and oogonios.
The sperm and oogonios
Sperm and oogonios are fungal cells Analogous to sperm and ovules. When joining, they make up zygotes from which new individuals arise. In the case of the reproduction through sporesthe process begins with the production of sexual spores in the gametangios, organs that in turn are formed in the progametangios. These are haploid cells that are generated by meiosis, so they receive in name of meiospores.
These spores can be:
- Ascospores: produced in the Ascas of the Ascomycetes.
- Basidiosporas: produced in the basidia of the basidiomycetes.
- CGOSPORAS either Zigospores: Produced in the zigomicostic cigosoporangios.
Regardless of the type of spore, this can be: spore + or spore –. For fertilization to occur there must be one of each type and the same species. After these spores unite their cytoplasms, they merger and form a cell called dicarion in a process known as plasmogamy; followed by the fusion of its nuclei, a process known as Cariogamia.
The resulting cell is a zygotea multinucleated diploid. This will form hyphae and subsequently be divided by meiosis to reduce its genetic load and cause more sexual spores.
Consult here what is the structure of fungi or what is the sporulation and examples in these posts of ecology see that we suggest.
Asexual reproduction of fungi
Asexual reproduction is the one that involves A single parent To generate offspring. The fungi originated from asexual reproductive processes are clones, which means that they have a load genetics exactly equal to that of your parent.
Fungi use asexual reproduction to colonize substrates because it generates much more offspring, it is faster and can be done more frequently than sexual reproduction.
Among fungi there are several types of asexual reproduction:
- Sporulation: It is the main asexual reproduction mechanism of fungi. It is executed through asexual spores known as mythospores because they originate through mitosis. Some fungi produce a single type of spores while others produce several different types throughout their life cycle.
- Gemmation: The fungus develops a yolk that multiplies by mitosis and ends up separating from the parent to live independently as a new organism.
- Binary fission or somatic cell fission: It is typical of yeasts. It occurs in unicellular fungi and consists of the mitotic division of a stem cell to form an exactly the same daughter cell.
- Soma fragmentation: A segment of the mycelium from the parent fungus is separated to originate a new individual.
Within asexual reproduction, asexual spores, conidiospores and sporangiosapras take part. Next, we will see them more detail.
Sexual spores
Asexual spores can be exospore or endospores. Let’s see what each of them consists of.
- Exospore or exogenous spores: They are the ones that are formed outside a specialized cell or apparatus, and not inside a sporangio.
- Endosporesendogenous spores or internal spores: they are the ones that occur in the conidia or sporangia: if they occur in the conidia (specifically in the conidioforos) they are called conidiospores and if they occur in the sporangia they are called sporangiospores.
The Conidiospores
Conidiospores can be arthroconidia, clamidoconidia or blastoconidia.
- Arthroconidia: They are formed by fragmentation of a thick partition.
- CLAMIDOCONIDES: They are formed by thickening of the HIFA
- Blastoconides: They are of blast origin and are formed by gemination.
The sporangiosapras
Esporangiosaporas can be zoospores or aplamps. Zoospores are uniflagellated or biflagellated mobile spores of smooth or bearded flagella produced in zoosporangios; and the flatoas are motionless spores without flagella.
Let us remember that asexual spores do not need to join with other spores; Well, just having favorable environmental conditions, they can germinate and give way to new clone organisms.
If you want to know more about the subject, do not hesitate to read this post about the Fungi Kingdom: what is, characteristics, classification and examples.
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