Oospore

Not to be confused with Oogamy

Oospores of Hyaloperonospora parasitica , agent of the downy mildew (in the middle)

An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and oomycetes. ^[1] They are believed to have evolved either through the fusion of two species or the chemically induced stimulation of mycelia, leading to oospore formation. ^[2]

In Oomycetes, oospores can also result from asexual reproduction, by apomixis. These haploid, non-motile spores are the site of meiosis and karyogamy in oomycetes. ^[3]

A dormant oospore, when observed under an electron microscope, has led researchers to draw conclusion that there is only a single central globule with other storage bodies surrounding it. ^[4]

References

1. Tronsmo, Anne, M. (2020). Plant Pathology and Plant Disease. CABI. ISBN   978-1789243178.
2. Uchida, J. Y.; Aragaki, M. (1980). "Chemical Stimulation of Oospore Formation in Phytophthora capsici". Mycologia. 72 (6): 1103. doi:10.2307/3759563. JSTOR   3759563.
3. Fry, William, E. "Introduction to Oomycetes". American Phytopathological Society. Retrieved 29 March 2021.
4. Ruben, D.M (May 1978). "Ultrastructure of Oospore Germination in Pythiumaphanidermatum" . American Journal of Botany. 65 (5): 491–501. doi:10.2307/2442581. JSTOR   2442581 . Retrieved 2021-04-04.