Zoospore in the context of "Attract-kill pattern"

Chytridiomycota are a division of zoosporic organisms in the kingdom Fungi, informally known as chytrids. The name is derived from the Ancient Greek χυτρίδιον (khutrídion), meaning "little pot", describing the structure containing unreleased zoospores. Chytrids are one of the earliest diverging fungal lineages, and their membership in kingdom Fungi is demonstrated with chitin cell walls, a posterior whiplash flagellum, absorptive nutrition, use of glycogen as an energy storage compound, and synthesis of lysine by the α-amino adipic acid (AAA) pathway.

Chytrids are saprobic, degrading refractory materials such as chitin and keratin, and sometimes act as parasites. There has been a significant increase in the research of chytrids since the discovery of Batrachochytrium dendrobatidis, the causal agent of chytridiomycosis.

The Oomycetes (/ˌoʊ.əˈmaɪsiːts/), or Oomycota, form a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms within the Stramenopiles. They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result of contact between hyphae of male antheridia and female oogonia; these spores can overwinter and are known as resting spores. Asexual reproduction involves the formation of chlamydospores and sporangia, producing motile zoospores. Oomycetes occupy both saprophytic and pathogenic lifestyles, and include some of the most notorious pathogens of plants, causing devastating diseases such as late blight of potato and sudden oak death. One oomycete, the mycoparasite Pythium oligandrum, is used for biocontrol, attacking plant pathogenic fungi. The oomycetes are also often referred to as water molds (or water moulds), although the water-preferring nature which led to that name is not true of most species, which are terrestrial pathogens.

Oomycetes were originally grouped with fungi due to similarities in morphology and lifestyle. However, molecular and phylogenetic studies revealed significant differences between fungi and oomycetes which means the latter are now grouped with the stramenopiles (which include some types of algae). The Oomycota have a very sparse fossil record; a possible oomycete has been described from Cretaceous amber.

A flagellum (/fləˈdʒɛləm/; pl.: flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores (zoospores), and from a wide range of microorganisms to provide motility. Many protists with flagella are known as flagellates.

A microorganism may have from one to many flagella. A gram-negative bacterium Helicobacter pylori, for example, uses its flagella to propel itself through the stomach to reach the mucous lining where it may colonise the epithelium and potentially cause gastritis, and ulcers – a risk factor for stomach cancer. In some swarming bacteria, the flagellum can also function as a sensory organelle, being sensitive to wetness outside the cell.

The chlorarachniophytes are a small group of exclusively marine algae widely distributed in tropical and temperate waters. They are typically mixotrophic, ingesting bacteria and smaller protists as well as conducting photosynthesis. Normally they have the form of small amoebae, with branching cytoplasmic extensions that capture prey and connect the cells together, forming a net. These extensions are dependent on the presence of light and polymerization of the actin cytoskeleton. They may also form flagellate zoospores, which characteristically have a single subapical flagellum that spirals backwards around the cell body, and walled coccoid cells.

The chloroplasts were presumably acquired by ingesting some green alga. They are surrounded by four membranes, the outermost of which is continuous with the endoplasmic reticulum, and contain a small nucleomorph between the middle two, which is a remnant of the alga's nucleus. This contains a small amount of DNA and divides without forming a mitotic spindle. The origin of the chloroplasts from green algae is supported by their pigmentation, which includes chlorophylls a and b, and by genetic similarities. The only other groups of algae that contain nucleomorphs are a few species of dinoflagellates, which also have plastids originating from green algae, and the cryptomonads, which acquired their chloroplasts from a red alga.

Chytridiomycosis (/kaɪˌtrɪdiəmaɪˈkoʊsɪs/ ky-TRID-ee-ə-my-KOH-sis) is an infectious disease in amphibians, caused by the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans. Chytridiomycosis has been linked to dramatic population declines or extinctions of amphibian species in western North America, Central America, South America, eastern Australia, east Africa (Tanzania), and Dominica and Montserrat in the Caribbean. Much of the New World is also at risk of the disease arriving within the coming years. The fungus is capable of causing sporadic deaths in some amphibian populations and 100% mortality in others. No effective measure is known for control of the disease in wild populations. Various clinical signs are seen by individuals affected by the disease. A number of options are possible for controlling this disease-causing fungus, though none has proved to be feasible on a large scale. The disease has been proposed as a contributing factor to a global decline in amphibian populations that apparently has affected about 30% of the amphibian species of the world. Some research found evidence insufficient for linking chytrid fungi and chytridiomycosis to global amphibian declines, but more recent research establishes a connection and attributes the spread of the disease to its transmission through international trade routes into native ecosystems.

Phytophthora infestans is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight. Early blight, caused by Alternaria solani, is also often called "potato blight". Late blight was a major culprit in the 1840s European, the 1845–1852 Irish, and the 1846 Highland potato famines. The organism can also infect some other members of the Solanaceae. The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C (54–64 °F) in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C (59 °F). Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C (68 to 75 °F).

Holomycota or Nucletmycea are a basal Opisthokont clade as sister of the Holozoa. It consists of the Cristidiscoidea and the kingdom Fungi. The position of nucleariids, unicellular free-living phagotrophic amoebae, as the earliest lineage of Holomycota suggests that animals and fungi independently acquired complex multicellularity from a common unicellular ancestor and that the osmotrophic lifestyle (one of the fungal hallmarks) was originated later in the divergence of this eukaryotic lineage. Opisthosporidians is a recently proposed taxonomic group that includes aphelids, Microsporidia and Cryptomycota, three groups of endoparasites.

Rozella (Cryptomycota) is the earliest diverging fungal genus in which chitin has been observed at least in some stages of their life cycle, although the chitinous cell wall (another fungal hallmark) and osmotrophy originated in a common ancestor of Blastocladiomycota and Chytridiomycota, which still contain some ancestral characteristics such as the flagellum in zoosporic stage. The groups of fungi with the characteristic hyphal growth, Zoopagomycota, Mucoromycotina and Dikarya, originated from a common ancestor ~700 Mya. Zoopagomycota are mostly pathogens of animals or other fungi, Mucoromycotina is a more diverse group including parasites, saprotrophs or ectomycorrhizal. Dikarya is the group embracing Ascomycota and Basidiomycota, which comprise ~98% of the described fungal species. Because of this rich diversity, Dikarya includes highly morphologically distinct groups, from hyphae or unicellular yeasts (such as the model organism Saccharomyces cerevisiae) to the complex multicellular fungi popularly known as mushrooms. Contrary to animals and land plants with complex multicellularity, the inferred phylogenetic relationships indicate that fungi acquired and lost multicellularity multiple times along Ascomycota and Basidiomycota evolution.